Program Bugs
Rather than a feature, if you notice some behavior of the calculator that isn’t what you expect or values that you believe to be incorrect, make a note of such things by adding comments to this page. You’ll need to create an account for yourself (if you haven’t already).
19 Responses to “Program Bugs”
By tzerrilla on Aug 29, 2008
Brett, I was trying to use the calculator for a $ 30 million project, and had some trouble after defining the loan parameters.
Could you determine whether the calculator has an upper threshhold ? It appeared that I had trouble after posing a loan amount over
$ 21.5 million or thereabouts.
Thank you for the wonderful tool, Brett.
Tony
By Bret Whissel on Aug 29, 2008
Hi, Tony. You had asked this question under Feature requests, and I had also answered there. (See the original.)
By robkluck on Dec 22, 2008
Hi Bret,
Great program. I punched in $185,000, 4.75% interest, $965.05 payment, 13 pmts/yr, and it said 331 payments (25.46 years). Seems like more years. Thanks. Rob
By Bret Whissel on Dec 22, 2008
Hi, Rob. More years than what? That extra payment per year that you’ve calculated has knocked off nearly 4.5 years from a 30-year mortgage. But note that this method may not accurately reflect the real payoff rate.
The calculator assumes that the payments are equally distributed throughout the year. If instead you make an additional payment at the end of the year, the 13-payments/year method will underestimate the amount of interest you will actually pay. To demonstrate, run the normal amortization assuming a 12-payment/year schedule, and look at the principal balance at the end of the first year. Now subtract your extra $965 from that balance (the one extra payment at the end of the year). Now run the 13-payment/year schedule as you had done and look at the principal balance: it’s nearly $22 less.
If the confusion is over the total number of payments, remember that 13 payments/year means there’s a total of 390 payments over 30 years in the schedule, not 360. So your 13-payments/year schedule eliminated 59 payments, not a mere 29.
I hope I didn’t confuse the issue for you. Let me know if you have any further questions.
By Andy on Mar 6, 2009
I have entered the following numbers in the calculator
Principal: 167895.00
Payments per year: 12
Annual Interest rate: 9.5
Number of payments: 180
Payment Amount: 1200.00
and when I calculate it shows a Balloon payment of 220773.25
Is there something wrong or am I doing something wrong
By Bret Whissel on Mar 6, 2009
With a 9.5% interest rate, the monthly interest payment is already over $1329. If you don’t pay at least that amount, you’ll owe even more the following month. If you want to figure out how much you need to pay monthly to liquidate the debt after 15 years, leave the “Payment Amount” field blank, and let the calculator determine that for you.
By Andy on Mar 6, 2009
In further analysing this, I think I have answered my own question. The monthly payment is not sufficient to even fully cover the Interest amount and therefore $0 can go to the principal reduction and so the principal increases each month by the shortfall.
By Andy on Mar 6, 2009
Sorry Bret, I made my second post before I saw yours. Thanks for your help
By earlreb on Jul 1, 2009
Today (July 1, 2009) I used the calculator to calculate a monthly payment. Then I changed the amount to see what the payment would be on the different amount–but the calculator did not change the payment amount. It threw a huge unknown number into “balloon payment” where I had nothing before. I had to close the browser and reopen the calculator to enter the new amount. You should be able to change the amount and recalculate a new payment amount.
Earl
By Bret Whissel on Jul 1, 2009
Hi, Earl. The calculator is behaving as it has been designed: the calculator looks for blank (or zero) fields to figure out what to calculate. So when you change a value in one of the fields, you need to blank out (or set to 0) the field that you wish to be re-calculated using the new values. By leaving only the Balloon Payment field blank, the calculator assumed that this is the value you wanted to calculate.
Bret
By DoubleN on Feb 11, 2010
I am trying to do a few amortizations for a 20-year annual payment, and when I hit the “Calculate” button, it changes my Principal amount so the result is very bizarre. When the principal amount is $361,400.00, for instance, the calculator suddenly turns it into $361. Is there something I can do to rectify this? I’ve tried to use other online calculators, but they seem to all be set up for monthly payments only. Thanks for any help you can provide!
By Bret Whissel on Feb 15, 2010
Hi, DoubleN. I’m guessing that the problem has to do with you typing in commas or other non-numeric characters. To enter $361,400.00 into a field of the calculator, type it as ’361400.00′ (without the quotes).
By DoubleN on Feb 15, 2010
That was it – thank you! (now why didn’t I think of that?)
By david on Jun 14, 2010
Hey Bret your amortization schedule is my favorite tool for what I do. I usually like to print out the schedule. tried this AM and all I get is Vertical lines where the numbers go . Can you help me on this one. The deck page prints fine …thanks
By Bret Whissel on Jun 14, 2010
Hi, David. Things look OK to me on the browsers that I use, but I will look into it. What browser and operating system are you using? Is it only the print function that’s not working properly? or does the schedule not display on the screen at all, either?
By Boan on Jun 15, 2010
Hi Bret,
When I print an amortization it always adds 3 additional pages of blank sheets. I have tried to limit the page to “1 of 1″ but it still prints 3 extra.
Great service to everyone. I have used your calculator for over 10 years.
Bob
By Bret Whissel on Jun 15, 2010
Hi, Bob. Printing is really a browser function, and try as I might, I haven’t been able to get my browser to duplicate the blank pages you’ve described. Still, I’ve tweaked the printing CSS further just in case. Can you try a different browser to see if it does the same thing? (Neither Firefox nor IE8 under Windows7-64 produce blank pages for me with the current calculator output.)
Bret
By esther on Jun 23, 2010
Bret,
can I calculate an interest only loan paying interest plus some extra to principal? it is a 30 year am with interst only for 10 yrs. I want to see what the balance would be after 10 years with the extra monthly payment.
By Bret Whissel on Jun 23, 2010
You can do this calculation in pieces. First, run the calculation as a regular 30-year mortgage, and have the calculator determine what the payment should be. In the “Summary” section, make note of what the “Interest Only” payment is. Now enter this amount in the “Payment Amount” field, plus whatever extra you want to add. Set the “Number of Regular Payments” to 120 (for 10 years), be sure the “Show Amortization Schedule” box is checked, and click “Calculate”.
The “Balloon Payment” field will now contain the expected principal payment *plus* another period’s interest payment. If you scroll down the amortization schedule to line 120, you’ll see the remaining principal in the far-right column. Now you can use the remaining principal to do a fresh 20-year amortization, if you’d like.
Bret