So I’m (hopefully) buying a house and I’m confused by the amortization tables. Is there a simple equation to calculate what the monthly payment would be for a 30yr fixed loan? As opposed to having to look it up for every case in a table. I want to make an excel sheet that will calculate payments depending on amount of loan, interest rate, and points, but I don’t know how they calculate the required amount of principle that’s paid on the first months payment.

Probably best to use someone else’s calculator - IMHO, the terminology used by financial types tends to get pretty obscure. Still, if you have too much time on your hands, I think the correct Excel formula is:

PV(rate,nper,pmt,fv,type)

Check the Excel docs for more details. Warning - if you’re using monthly periods, the interest per period is AnnualRate / 12. Otherwise, you get really strange results. Which is to say - use someone else’s calculator.

Thanks for the replies. I’d found the online calculators, but I wanted to have all the other numbers I’m playing with calculated, too (points, remaining savings) and have the different percentage loan results all visible on one sheet.

wolf_meister: your equation was very helpful. I came across a more detailed version here that works out to be the same as yours.

CurtC: I’d tried looking up amortization and mortgage in Excel help and couldn’t find those, but they also look like the same equation- thanks.

Civil Guy: That’s basically it- trying to play with the downpayment and other variables to see what my monthly would be- and looks I may now be able to do it.