Credit Card Payoff Calculator
How long will it take to pay off my card at a fixed monthly payment, and how much interest will I pay?
Single calculationv1.0.0Verified 2026-11-01Runs in your browser
Spec sheet
nper_fixed_payment · v1.0.0Method
Number of periods (numpy-financial nper) + month-by-month schedule
- 01
r = APR ÷ 12 - 02
n = ln(z / (B + z)) / ln(1 + r), z = P / r (npf.nper) - 03
Interest each month = balance × r, rounded to the cent
Limits — read before relying on it
- Assumes no new purchases, fees or rate changes, and interest compounded monthly on the statement balance.
- Card issuers compute interest daily on the average balance; real totals can differ slightly.
Sources