Excel formula to calculate credit debt reduction

Excel has numerous financial functions including PV, PMT, RATE, INT, IRR and others. If you post a specific problem someone can help. For reference,John Walkenbach's book Excel Formulas is recommended

Thanks. Here is an example of what I'm trying to calculate. Say you owe $8000 on a credit card that has a annual interest rate of 13.9%. So I'm trying to calculate how many months it will take to payoff the $8000 with a monthly minimum payment of $100.

Thanks

Hi
You need to use the NPER function. If the interest rate is 13.9% pa the monthly amount is either 1.15833% (13.9/12) or 1.09049% (1.139^(1/12)-1) if the rate is compounded monthly. The formula is therefore either:
=NPER(1.15833%,-100,8000,0) or
=NPER(1.09049%,-100,8000,0)

If the payments are due at the beginning rather than the end of each month the formulae are:
=NPER(1.15833%,-100,8000,0,1) or
=NPER(1.09049%,-100,8000,0,1)

Depending on the interest rate compounding the answer is either 227 or 190. I expect your bank will use the 1.15833%.

Thank you very much.