financial function

[wen22222]

Hello. I just bought a house and used the PMT and PPMT function to
calcualate payments, interest, principal on my loan. Is there a function to
calculate the effect of paying additional principal? For instance, the PMT
function calculates a monthly payment of 878.23. I want to be able to figure
out how much time will be cut off if I paid 950 per month.

Thanks.
Wendy

 

[joeu2004]

the PMT function calculates a monthly payment of 878.23.
 I want to be able to figure out how much time will be cut
off if I paid 950 per month.  

As long as the excess monthly payment is constant, use NPER.

For example, a $100,000 loan at 6.6% with monthly payments of 878.23
is paid off in 15 years (last payment is $381.40).

If you pay 950, NPER(6.6%/12, -950, 100000) is 158 months (rounded
up), which is 13 years and 2 months (last payment is about $666).