# Checking the math on a Truth-in-Lending Disclosure

Here is a shot of an actual Truth-in-Lending statement for a real home mortgage (mine). I'm trying to check the numbers but they seem slightly off:

It's a 30-year fixed rate mortgage. The annual percentage rate is 5.542%, and the total amount financed is \$148,880.20.

I want to compute the monthly payment. I use the formula here: (https://en.wikipedia.org/wiki/Amortization_calculator)

A = (P i) / [1 - (1+i)^(-n)]

with i = .05542 / 12 and P = 148880.2 and n = 360.

My computation gives a monthly payment of 849.25, rather than 851.57 claimed on my document.

Am I reading something wrong with the document? I assume this isn't a simple calculation error from the mortgage company- what else could account for the discrepancy?

• It's preferable to make questions as self-contained as possible. If you can include the relevant information from the TIL sheet, that would be better. You might get more answers.
– user32479
Nov 10, 2015 at 15:01
• @Brick I did include the relevant information, didn't I? I also linked the TIL sheet just so people could see if I'm reading it wrong. Nov 10, 2015 at 15:25
• It would be better if the TIL image were directly in the question so that the question has stand-alone archival value. You probably can't post an image though since you're a new user, so maybe this is the best you can reasonably do.
– user32479
Nov 10, 2015 at 15:50
• @Brick- exactly right. You're welcome to post the image into the question if you're allowed to. Nov 10, 2015 at 16:57
• Did your loan close on approximately July 13, 2005? If you did not pre-pay the first 18 days interest, then about \$ 400 of extra interest got capitalized. (\$ 412.55 using a 30 day month; \$ 406.90 using a 365 day year; \$ 406.62 using a 365.25 day year; \$ 405.78 using a 366 day year.) The discrepancy you found corresponds to an initial value of \$ 406.22. Nov 10, 2015 at 20:52