Questions
If you have a question about the calculator or about amortization, attach a comment to this page. But please, be sure you’ve checked the FAQ Page first. (You’ll need to create an account to post a comment.)
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80 Responses to “Questions”
By Trish Bennett on Jul 30, 2008
Bret,
First, THANK YOU for providing this calculator! Second, is there any way to get a calculation of interest only (compounded monthly) for the first 6 months, then principal and interest compounded monthly thereafter? Any creative suggestions would be appreciated!!!
Trish Bennett
By Bret Whissel on Jul 30, 2008
Hi, Trish. The calculator does not presently accommodate the scenario I think you’re describing. Let me make some clarifying assumptions here: Let’s assume that you wish to have a 30-year amortization, monthly payments, for which the first six payments will be interest-only.
In this case, you really have a 354-month amortization (instead of 360). If you are making interest-only payments for the first 6 months, the principal balance doesn’t change at all. The interest-only payment amount will be on the first line of the amortization schedule, under the “Interest” column. After the first 6 interest-only payments, the payment amount would increase to the “Regular Payment” amount, and the amortization begins.
If you’re not making *any* payments for 6 months and you wish to accrue the the unpaid interest as additional principal for when payments start, there’s a formula for calculating the new principal (see Additional Payment Tweaks for info).
By bryan on Jul 30, 2008
Bret,
I am a Realtor who is currently (and unsuccessfully) attempting to build my first professional website. I would really like to use your calculator on my page or link to your page. My site will have a disclaimer so you would be covered from that. Would this be ok?
Bryan
By Bret Whissel on Jul 30, 2008
Hi, Bryan. It is not possible to run the calculator in its present form from your site. However, you are free to link to the calculator page if you like.
Best wishes on your website!
By colleen on Aug 20, 2008
Thank you so much, Bret, for a really user-friendly calculator, which is helping to save me from a usurious predatory lender. I have a fixed interest rate, but the lender has been behaving otherwise.
You are awesome! But I probably won’t write too often, because the password you gave me is a real tongue-twister.
Colleen
By Bret Whissel on Aug 20, 2008
Hi, Colleen. Knowledge is power, and I’m delighted that folks are able to use information the calculator provides to avoid becoming victims of unscrupulous lenders.
I can’t take credit for the tongue-twisting password, though. The blogging software hands those out automatically. But I suspect you may be able to change your password if you edit your profile. (I don’t see the same screens you do, so I’m not sure where to tell you to look.)
By mfsystem on Aug 22, 2008
Bret,
First, THANK YOU for providing this calculator! I’m a trainer with Mortgage Freedom System.com & The way you present Interest and Principal is awesome.
Nicola Dupont
By odieo on Aug 24, 2008
Thanks….this is a great tool. Some of my borrowers wish to make additional payments to principal from time to time. How can I refigure the schedule,or can I? I sure hope so, because I don’t want to hand calculate….if even I could figure out how!
By Bret Whissel on Aug 24, 2008
First, see the FAQ, Question #7 for part of the answer if the extra payment is consistent.
If the extra payment is irregular, then you will either have to use a spreadsheet to generate the table, or you could use the calculator, resetting the principal amount after each extra payment and running the scenario again. This doesn’t allow you to run a whole schedule, just parts of the schedule at each run.
By Edna Tx on Sep 16, 2008
Bret
I have used your site for amoritzation calculator and what I liked alot better than others it printed a lot larger than others. I went to print another schudule today and it was only half the size as the last one. I have my computer set on the largest print but it still didn’t print as large as the last one I printed on 1/9/2007. Is it my new printer or have you changed the size of the print? Is their anything I can do to make it print larger because I really do require the larger print. Thank you so much for your site Edna
By Bret Whissel on Sep 16, 2008
Hi, Edna. Printing is a function of your web browser, but depending on your browser, you can configure it to print the data larger.
I’ll assume you’re using Internet Explorer. First, run your amortization schedule as normal. When you’re ready to print, go to the “File->Print Preview…” In the toolbar at the top of the window, you’ll find a drop-down menu with “Shrink to Fit” listed. Select some larger size, like 125%, 150% or something else that works for you. Then click the printer icon on the left of the toolbar to print.
I hope that works for you. Let me know.
Bret
By Edna Tx on Sep 16, 2008
Thank you Bret, it worked. Now my husband and I can easily see the numbers. Edna
By maximus on Oct 16, 2008
I’m building a website with an amortization calculator. I need one of two things: 1. I need to know what’s the formula to build this calculator or 2. Can I purchase the code?
In advance, I thank you.
By Bret Whissel on Oct 16, 2008
Hi, Maximus. The calculator source code is not for sale at this time, for lots of reasons. The formula for amortization is available in this document, which contains my own derivation. You’ll find a traditional presentation of the formula at the Wikipedia.
By keithtaggart on Nov 1, 2008
I just wanted to commend you on the high quality and professional appearance of your calculator. I am a licensed broker in Oklahoma and use it frequently for my transactions.
Thank you,
Keith Taggart
By Fred Deming on Nov 3, 2008
Bret,
Any objections or issues with hosting a link to your calculator on my company’s website?
Thanks.
By Bret Whissel on Nov 3, 2008
Keith, thanks for the kudos!
Fred, I have no problems with links to the calculator. Link away!
Bret
By christophermusic on Nov 13, 2008
Bret,
Thank you for the calculator and for designing it with such excellence. Your site is awesome. I read your two essays and I thought they were awesome.
By Bret Whissel on Nov 13, 2008
You’re welcome, Christopher(?), and thanks for taking the time to read the other stuff. I’m gratified to know that at least one person thought it was worth his time.
Bret
By Darsissy on Nov 20, 2008
Bret,
I have found your calculator very useful so far. My husband and I sold our business 5 years ago and financed it ourselves and no amortization schedule was ever made out for us. Although the terms of the contract are complicated (the interest rate changes yearly, then every other year and with weekly payments) I have it figured out up until the point that they quit paying us. Now I need to figure out how the interest accrues for those weeks until they resumed payments. I’ve tried a few things but I can’t seem to figure out how to do this. Is this something the calculator can do or do I need to get help from another source?
Darlene
By Bret Whissel on Nov 20, 2008
Hi, Darlene. The calculator is limited when it comes to complicated scenarios such as the one you describe. The basic assumptions are that the interest rate and payment amount remain constant through the amortization period.
I am not an accountant or finance person, so I shall refrain from advising you about how interest should accrue during the lapse period you’ve described. This is something that might be addressed by the sales contract, so you may wish to seek out professional advice.
By rjs0014 on Dec 11, 2008
Bret,
I just wanted to thank you for creating and maintaining this calculator. I’ve got a ton of student loan debt, from several different companies, and this has been an invaluable tool in estimating repayment. Figuring out the overall effect of putting $100 extra into Loan 1 each month versus Loan 2 was difficult, until I started plugging numbers in here.
Now I feel as though I’ve got a solid grasp on things. Thank you so much!
By Bret Whissel on Dec 11, 2008
Hi, RJS. I’m always pleased to know that the calculator has been helpful. I find it empowering to make repayment decisions based on various test scenarios, seeing how the numbers work out.
Best wishes!
By brenda on Jan 22, 2009
hello Thanks so very much for such a flexible tool! Can you tell me how the interest rate is compounded? We want to set Our interest rate compounded semiannually What is your set for thanks again…brenda
By Bret Whissel on Jan 22, 2009
Hi, Brenda. The calculator assumes that the interest compounding periods are the same as the payment periods. At present, there is no way for you to change this behavior.
So right now, the periodic interest rate is calculated by dividing the annual rate by the number of annual payment periods.
By samdnaman on Feb 4, 2009
hi bret
great calculator , i am trying to figure out what formula is used to get to actual payment amount .
here is the problem :
loan amt 375,000 12 % rate , 5 eqaul annual payment = the calculator gives me 104028.65 per year HOW DO I GET THIS NUMBER = what is the formula please .???
By Bret Whissel on Feb 5, 2009
If you click on the “CALCULATOR” menu item at the top of the page, among the links you’ll find my derivation of the amortization formula. The last equation in that document is the basis for the calculator’s computations.
You can find other discussions of the amortization formula by Googling or visiting Wikipedia.
By cheflouise7 on Feb 16, 2009
Hi Bret,
I have a question about my mortgage. I have a 30 year mortgage, 6% and have already paid into the mortgage for 5 years. My balance at this point is $105,621.63. My monthly payment is $1,357.24. This includes principal, interest and escrow. I have just applied to my bank to change my monthly payments to biweekly with two payments of the year (since there are 26 instead of 24) to go directly to the principal. According to Citibank, I should finish my mortgage 7 years early by doing this. If I pay an extra $50 a month, they say I should finish 9 years early and $100 a month gives me 11 years early. How can I get these figures to show on an amortization schedule so I can get a clear picture of my different options?
By Bret Whissel on Feb 16, 2009
Hi, Chef Louise. The first thing you need to know is what the P&I payment is, excluding escrow. (Escrow usually covers current taxes and insurance, and is not a loan amount to be repaid. This will be fixed/variable as tax and insurance rates/amounts change.) I plugged your principal balance, the 6% rate, 12 payments per year, and 300 remaining payments into the calculator to get a monthly P&I of $680.52. (If this doesn’t agree with your real P&I, perhaps you’ve already done some acceleration, or maybe the number of remaining payments is off by a few months.)
For acceleration purposes, the bi-weekly P&I is often just half of the former monthly P&I, so the acceleration really comes from making the equivalent of one extra monthly payment per year. So plugging $340.26 into the payment amount field, changing the payments/year to 26, and clearing the number of regular payments, the calculator shows that the payments remaining to be 547, or roughly 21 years. That’s an improvement of only 4 years, not 7, so your P&I may be different.
Now you may add $50 to the bi-weekly payment (i.e., $390.26) to see the payoff time reduced to 16.4 years, or $100 (i.e., $440.26) to see the payoff time reduced to 13.5 years. (Remember to zero out the “Number of Regular Payments” field each time you try a new payment amount.)
By hpytrvlgrl on Mar 7, 2009
Hi Bret… Thanks for providing a great service! I need to print an actual amortization schedule for a loan that closed on 10/23/07 for $107,000.00 at 6% with the first payment due on 12/1/07. The payments are $641.52 — it seems that your calculator does not allow for the interest between the closing date and the first payment…. or am I missing something? I never did have a mathematical mind… I’m sort of numbers dyslexic…..lol… A million thankeroos! Karen a/k/a hpytrvlgrl
By Bret Whissel on Mar 7, 2009
Hi, Karen. The calculator does not calculate additional interest because of fees or delays in the start of amortization payments. But check your closing documents carefully. You may find that an extra month’s interest (plus 8 days) have been included in your closing costs. When a closing comes near to the end of month, I think it is common practice to skip a month, but the lender adds the interest due for that “skipped” payment to the closing costs. If so, this figure is not part of the principal: you actually paid it ahead of time, so it is not figured into the amortization anyway.
By hpytrvlgrl on Mar 7, 2009
Well….. whoda’ thunk? lol Yep, you were right…. all taken care of in the closing docs…. Thanks for your quick response!! And thanks for sharing your writings – they’re very good!! I’m going to pass them along to some other interested parties and I’m guessing your “Love & Union” will be plagarized at weddings for some time to come…. it was so well said!! I also believe that most of us don’t hear God because we don’t take the time to listen…. so I’m glad you did!! Take care and God Bless! Karen
By hpytrvlgrl on Mar 7, 2009
Geeeeeezzzzzz….. this is a “one-stop shop”…. now I’m listening to your music….lol Is there any way to get a pizza delivered?
By Bret Whissel on Mar 7, 2009
Oooo, Pizza! One of my favorite foods! But sadly, I think you’re out of my delivery range, so there’s no 30-minutes-or-less guarantee.
So you think people will want to hear about the “superposition of quantum states” at weddings, huh? You may know stranger people than I do.
And I’m glad you figured out your loan info, because that means that the calculator works right.
By kjohnsonm on Mar 9, 2009
Is it possible to make a new feature or can you recommend a site that compares when a refi is a good bet compared to an existing load? I use your site all the time to by things from my house to cars and what have you, however I am looking at trying to find out what interest rate is the sweet spot to make a refi a good deal and what the payback time might be for points and fees? -Keith
PS so far as I can tell in my load it looks like 2.5 years pay back if I go down to 4.5% and 2.3 yr for 4.375% etc.
By Bret Whissel on Mar 12, 2009
Hi, Keith. I don’t think the calculator will be able to do loan comparisons any time soon. The kind of information to be supplied and the calculations to be done are very different from what the current calculator does.
I’m sorry I don’t have any recommendations for you.
By Kathyp on Mar 19, 2009
I hold a note that the borrower cannot seem to supply adaquate insurance. I need to add insurance premiums for a couple of different years. Can you explain how I could do that?
By Bret Whissel on Mar 24, 2009
Hi, Kathyp. While insurance premiums may become part of a payment, like escrow payments, they are not part of an amortization, which involves only principal and interest components of a payment. The calculator deals only with P&I components of a payment schedule.
By John Joesph Mollitor on Mar 29, 2009
Hi Bret; Thanks so much for the calculator which I have used a few times. I have read some of your postings, and am intrigued by them. I have written lyrics for 40 or more songs over my 70 years time span. (I’m sure none compare with the depth of your writings.) I play the guitar, by ear, I need to learn to write my music down before life is gone. Any suggestions? You seem to be a remarkable person, Thanks for being you.
By djbertus on Mar 30, 2009
First let me say thanks for supplying this calculator. For someone who is not a math guy it is quite helpful.
My question is this. I have a promissory note in the amount of 68,676.10. There are to be 9 quarterly payments of 7,023 at 7% interest and a balloon payment at the end with the last quarterly payment.
Your calculator matched that of the borrower. However, the borrower missed the first payment. After 15 days late the interest rate goes to 9% until the default is cured.
My question, as simple as I can describe it is this: The loan was made on 10/01/08 and the first payment which was due on 01/01/09 was made on 3/30/09. The borrower is claiming that he only owes the 2% spread for the 75 days (286.12). I claim that an additional 7% on the principal is owed for 15 days and 9% for the 75 days (1,488). I guess the question is in an amortization schedule does the 1201.83 in interest due on the first payment represent interest from 10/01/08 to 01/01/09 or from 01/01/09 to 03/31/09.
I appreciate any thoughts whether specific numbers or otherwise. Thanks.
By Bret Whissel on Mar 31, 2009
Hi, JJM. I’m flattered that you think well of what I’ve written, and I thank you for taking the time to let me know.
Learning to transcribe music is a skill that may take some time to master. To start, it would help to have a basic knowledge of music notation, and I’d recommend that you find a book on learning to read music, or find a patient musician friend or relative who would be willing to teach you.
While you’re working on your musicianship skills, I’d also recommend that you start to record your songs. It doesn’t take much equipment. Even with the basic sound card on your computer, you may be able to simply plug in a microphone and start recording your songs digitally. In this way, the definitive rendition is available to posterity, but the transcription process can develop at your leisure.
Best wishes!
By Bret Whissel on Mar 31, 2009
Hi, DJBertus. I’m sorry, but I don’t know that I can comment on your situation. I am not a lawyer or a banker, and this seems more a question of terms of contract than of mathematics. Perhaps you should consult with a lawyer or accountant.
But as to the question about the amortization process, the interest part of the payment covers the span of time between payments (or the start of the loan). So the payment due in January includes interest covering the period from 10/1 to 1/1. If that payment is not made in time, then the calculation of interest for the next payment will be incorrect, since it was determined based on the projected outstanding principal if the first payment had been made as scheduled.
Good luck!
By djbertus on Mar 31, 2009
thanks for your response Bret. I realize you may not be able to comment on specifics. I just wanted to be sure my understanding of the math was correct. It would seem to me that if the oposite were correct it would be an interest free loan until the first payment was made.
God bless and thanks again for creating the calculator.
By David the Realtor on Apr 3, 2009
I need an ammortization calculator that will enable me to enter all of the criteria (original principal balance, interest rate, term, etc.) and will also allow me to enter the actual amount paid and the date that the payment was actually posted. The ammortization would need to recalculate the remaining balance each time a payment and amount are entered. The interest rate also needs to be able to be changed periodically as the loan has re-set provisions.
Do you know where I can find this type of ammortization schedule?
By Bret Whissel on Apr 3, 2009
Hi, David. I believe I have seen a commercial product that does what you require, but I don’t remember what it is off-hand. I’m sure it will turn up with enough googling.
By ybynum on Apr 16, 2009
I want to thank and commend you on your calculator. I have entered “amoritization table” in the search engine for many months, today was the first time your site popped up. On first use I was able to get exactly what I wanted. My mortagers have been losing and misapplying my mortgage payments for months and I wanted to make sure I wasn’t beeing cheated. It appears my balance due after a year and a half is about on target. I will be using your site in the future.
By Jennie Cunningham on May 6, 2009
Hello Bret, Greetings from Australia. I use your amortization calculator all the time, and it’s spot on! I was unable to find an Aussie calculator that was easy to use. So congratulations! Also note you use the 12 Apostles picture (located in Victoria) at the start of your blog. (Although there is only 10 now). All the best Jennie
By Bret Whissel on May 6, 2009
Hi, ybynum. It is always a relief to have information validated from another source. I’m glad, for your sake, that you’re not being cheated, and I’m pleased to know that the calculator has been helpful in this regard.
And hello to you, Jennie! Nice to hear from someone so far away! So what happened to two of the Apostles? Have they become heretics and banished from the coast?
or has a rising sea from climate change consumed them?
By Mo_Cheng on May 7, 2009
Hey Bret
Thanks for hosting the calculator on the net. Your application is what I’ve been checking my amortization calculations for years!
I’ve ran into a bit of a situation, which from what I can see your calculator doesn’t handle. Do you know how to calculate a loan which has multiple interest rates? For instance:
the first 100 dollars of principle amortized @ 15% using 5 payments
the second 100 dollars of principle amortized @ 35% using 5 payments
the third 100 dollars of principle amortized @ 40% using 5 payments
for a total of a 15 payment loan. Terms can be monthly, weekly, bi-weekly, etc..
Do you know where I could find a formula which in layman’s terms explain the calculations? Im trying to program an amortization formula which will handle the loan above.
Mo
By Bret Whissel on May 7, 2009
Hi, Mo. I don’t think I fully understand the situation as you’ve described it, and neither do I have a clue where to find a formula for this type of loan scenario.
Good luck!
Bret
By Mo_Cheng on May 11, 2009
Its okay. We’ve decided to put particular issue aside. I do however, have another question.
It seems like your calculator rounds the interest amounts when calculating the payments. Do you round the numbers? If so, which decimal do you round it to? Im currently truncating the numbers, totaling them up and adding them to the last payment. The result is variable, but we seem to be a few cents + or – every time.
By Bret Whissel on May 20, 2009
Hi again, Mo. Yes, the calculator does indeed round each interest payment to the nearest whole penny. (Maybe banks can pay each other off in fractional pennies, but the rest of us mere mortals are constrained to whole cents.) Because each interest payment has been rounded, the final payment may be larger or smaller than the standard periodic payment.
Bret
By Phil on May 26, 2009
I really like your calculator and use it almost daily for my work. However, that boggle-head ad for the mortgage rates is so distracting that I can’t keep the page up. I know you need to offer advertising to fund your work, but that particular one is pretty bad. Thanks
By Bret Whissel on May 27, 2009
Hi, Phil. Until now, I had no problem with the Google Ads that had been placed automatically on the calculator page. But I think I just saw the ad to which you’re referring, and I agree, it is obnoxiously distracting. I don’t know if there’s a configuration option that will allow me to dial down the obno factor, but I’ll take a look!
Bret
By leb on Jun 1, 2009
Bret,
Your loan amortization utility is quite handy. It is the first one which comes up on a Google search so I am guessing that is why so many people find your blog. The more people who use it, the more it will come up first on any future search.
Here is the problem. The advertisement with the lady screaming (re loans) was SO absolutely, incredibly obnoxious and annoying that I could hardly stand to finish the download I was doing. It took every ounce of effort not to go off to another site for the calculations. It was bad, Man.
I mean we are not just talking annoying here or even mildly obnoxious. We are talking majorly, industrial strength obnoxiousness as in a really, really BAD ad ….. on an otherwise perfectly nice site. I’d look into that and put some restrictions on what they can put up there by way of advertising. To say that this ad got on my nerves while I was downloading would an understatement of the order of saying that the bomb when dropped on Hiroshima created a little disruption to the routine daily business
LEB
By Bret Whissel on Jun 1, 2009
Hi, LEB. I agree. After Phil’s similar comment, I tried to see if there was a way to filter that particular ad, but I was unsuccessful. Recently, Google has provided a way to preview ads, but this particular ad was not listed. After digging around some more, I think I may have found a way to filter this particular advertiser, so I hope to have this annoying image purged soon.
Bret
By leb on Jun 1, 2009
Great news! Here is yet another approach. Perhaps you could forward our comments (Phil’s and mine) to the company which posted the obnoxious ad. When they see how people are reacting, perhaps THEY will pull the ad, themselves. On the other hand, you have to wonder about someone or someones who created that obnoxious thing in the first place.
If they realized the negative effect their ad was having on people – i.e people navigate away from the site BECAUSE OF this very ad, they might think twice about retaining it. As I said, it is a serious blemish on an otherwise very nice site.
By Bret Whissel on Jun 1, 2009
Hehe, I have already gone to the companies’ websites and sent messages that I was attempting to filter their ads because of the annoyance factor. Maybe they’ll reconsider their strategy.
It is interesting to me that, in one sense, the ad is effective because it draws attention. But it doesn’t take long before it has the opposite effect. Though I’m not a violent person, I begin feeling compelled to slap that screaming, bobble-headed woman, and I don’t think I’m alone in that sentiment.
(For those who haven’t a clue what we’re talking about, here’s a link to the ad: http://www.fetcharate.com/cre/4/scream.swf)
Bret
By jtda on Jun 14, 2009
Hi, Bret. Nice tool.
I used it a few days ago but couldn’t find it after I closed my browser. Finally, I remembered that I had originally searched for ‘amortization’ but was now searching ‘mortgage calculator.’ Maybe you’d get more hits if you included the word ‘mortgage’ on your calculator. I’m sure the Google ad dollar$ will roll in.
Take care!
James
Houston, TX
By Bret Whissel on Jun 19, 2009
Hi, James. In fact, the calculator does show up on a search for ‘Mortgage Calculator’, but it’s buried back a few pages. There’s a lot more competition with those particular search terms. The calculator can’t be everything for everybody, so I’m content to let the calculator stay within its particular niche.
Thanks for looking out for me!
Bret
By ednarich on Sep 9, 2009
Can you please explain what minimum amortizing payment means?
“Minimum amortizing payment for this Principal and Interest rate: $1977.51″.
Thank you very much. Edna
By Bret Whissel on Sep 9, 2009
Hi, Edna. The “minimum amortizing payment” is the smallest payment that will eventually pay off the loan. It’s an estimate, theoretically one penny over the interest-only payment. (The interest-only payment doesn’t reduce the principal at all, so one would never pay off the loan if only paying the interest.)
Bret
By viking on Sep 22, 2009
Hi Bret,
I wonder if you know if it possible to get a closed form equation for Total Interest Paid after N monthly payments?
There is a function for this in Excel (CUMIPMT), but I have not been able to find the equation for this.
Actually, what I am *really* after is a formula for the reverse, solving for N. In other words, I already know the Total Amount Interest Paid, but would need to calculate how many months have been paid.
TIA!!
By viking on Sep 22, 2009
One more thing; I am a little confused about the calculator.
I input the following data:
Principal=$10,500; payments/year =12; Annual Rate=11.22%; Number of Payments= 7; Monthly Payment Amount= $344.87
The calculator shows that Total Payments= 8 and Total Interest Paid=$719.60.
To compare, I created an (Excel) amortization Table. In my table, the Total interest paid is the same as yours: $719.60 after 8 payments. However, why do I need to enter 7 payments in the calculator to get the results after 8 payments?
Furthermore, the final Balloon Payment should be the same as the remaining balance after the 8th payment, which in my case = $8,460.79 while your Calculator calculates: $8,805.65!?
Thanks again!
By viking on Sep 22, 2009
Ops, Bret you can delete my 2nd post.
I just realized what you were doing; The last month’s interest is included both in the Balloon payment and in the Total Interest Paid (this was a bit confusing)
In your case:
.
Total Paid= 7*$344.87+$8,805.65=$11,219.60
in my case:
Total Paid= 8*$344.87+$8,460.79=$11,219.60
End results are the same
By Bret Whissel on Sep 23, 2009
Hi, Viking. Yes, interest is accounted for in the Balloon Payment, as it’s assumed that the Balloon Payment occurs one full payment cycle after the last Regular Payment.
As for your first question regarding Total Interest Paid after N payments, before I can answer, I need to know what the known quantities are. (I.e., do you know the interest rate? the payment amount? the length of the amortization period? etc.)
By viking on Sep 23, 2009
OK. We can use the example above, strying to solve for N:
Principal=$10,500; payments/year =12; Annual Rate=11.22%; Monthly Payment Amount= $344.87; Total Interest Paid=$719.60.
Unknown: Number of Payments (N)
(From your calculator, it turns out that N=8).
However, I need the actual formula for N as a function of the known variables.
Thanks in advance!
By viking on Sep 23, 2009
p.s. Not to sidetrack the issue, but the original problem is slightly different.
In this case, I didn’t know the Total Interest Paid, but instead the Total paid; per the example above:
Total Paid= 8*$344.87+$8,460.79=$11,219.60
and I needed to find N.
However, I realized that Total Interest Paid = Total paid-Principal=$11,219.60 – $10,500= $719.60.
Thus, the two situations are basically the same.
By viking on Sep 23, 2009
Wish that I could edit my posts…..
Forgot to mention that the amortization period is 36 months
By Bret Whissel on Sep 30, 2009
So if anyone has been following along and wonders about Viking’s question, I have not been able to find a closed-form solution for calculating the number of payments. The equation eventually comes down to something in the form [ ax + b = cx ] (solve for x). If there is a solution that does not involve iteration, I don’t know of one.
By geowithquestion on Oct 1, 2009
Hi Bret,
I’ve used your calculator more times than I can count over the last few years. Thanks for creating it. I am writing to request a calculator with different input parameters. There are loans out there (I have one with a credit card co. and am considering another with my bank) where your monthly payment is based on paying a percentage of the principle plus interest on the principle. For example, the one I have with the credit card is based on paying 1.5% of the principle plus 3.99% interest for the life of the loan. It’s a fairly agressive pay down scheme that I like, but I cannot find a calculator with a payment schedule. Do you know if one? Would you considr creating one?
Thanks and best wishes.
By Bret Whissel on Oct 2, 2009
Hi, Geo. I’m not familiar with this repayment scheme, and it seems like there are some details left out. I don’t know of such a calculator, but it seems like the math for such a scheme wouldn’t really require a specialized calculator.
By gth48 on Oct 4, 2009
Brett, My apologies but I am needing some help, and cannot figure out how this would be entered..I am not that smartest student in the room…especially in Math. So here goes….a 25,000.00 loan ..no payments for 168 months, at a 8 percent interest would come out to how much? I am sure this is not rocket science..I just can’t get it.
By Bret Whissel on Oct 6, 2009
Hi, gth48. The calculator is not designed to do the sort of calculation you’re asking, as you’re not actually performing an amortization. Instead of an amortization calculator, you just need some sort of an interest calculator.
There are at least two questions to which you need to know the answers before you could make this calculation accurately: (1) How is the annual interest rate turned into a periodic (i.e., monthly) rate? (2) Is the interest compounded, and if so, on what basis? or is it simple interest?
You can probably find some help for this calculation if you search for “compound interest calculator” or “simple interest calculator”.
By stampman on Dec 6, 2009
My question is this…
I understand that if you take your monthly mortgage payment and divide that amount by one-half and pay it twice a month your payoff time on a conventional 30 year mortgage will be reduced by approximately 7 years. If this is true, how can one demonstrate this using your loan amortization calculator? Thanks.
By CamKap on Feb 8, 2010
Can I purchase your program as a stand alone program.
Ken
By Bret Whissel on Feb 15, 2010
Hi, Ken. I do not have a stand-alone version of the program available at this time.
By Bret Whissel on Feb 15, 2010
Hi, stampman. I suspect that the loan acceleration program you’re talking about is just a little different than you’ve described. Usually one makes payments every two weeks, not twice a month, and because one is paying half the regular mortgage payment every two weeks, then the equivalent of one extra monthly mortgage payment is paid every calendar year (26 bi-weekly payments instead of 24 twice-monthly payments). You can test these payment schemes by changing the number payments per year to 26 (or 24). Then set the payment amount to the bi-weekly (or twice-monthly) amount, clear the number of regular payments field, and click calculate to see how much of the loan you’ve lopped off.
By C S Schwartz on Mar 5, 2010
Brett, thank you SO MUCH for the calculator! I use it several times a month. However, today I encountered a problem with the calculation of interest. I plugged in $5500.00@ 10.25% for 4 payments, 24 payments/yr. The total interest paid is listed as $54.71. I think it should be more along the lines of $93.95??? I would appreciate your input on this. And thanks again for this great tool!
By Bret Whissel on Mar 5, 2010
Hi, C.S. The interest calculation looks correct to me given the numbers you’ve provided. However, maybe you really wanted the payments to extend over 4 months, rather than 4 payments? (Specifying 24 pmts/year, 4 payments = 2 months.) If this is the case, then the interest turns out to be $106. 7 payments gets closer to the your expected value with a total interest of $94.36.