Credit Card Calculator

How it works

Why a fixed card payment matters

A credit-card balance can take much longer to repay when the payment only slightly exceeds the interest charged. The fixed-payment mode helps you compare larger regular payments on the same balance. This projection assumes the modeled balance and rate, rather than reproducing every issuer's statement rules. New purchases, changing rates, or additional fees can alter the actual payoff path.

Loan & schedule: formula and assumptions

Payment = P × r / [1−(1+r)^−n], where r is the monthly rate.

Equal monthly payments amortize a fixed-rate loan. Extra payments reduce principal after the regular payment.

Fixed-payment payoff: formula and assumptions

Payoff months = −ln(1−Pr/payment) / ln(1+r).

The monthly payment must exceed the interest due. The final installment is reduced to the remaining balance.

Worked example

Reference example currency: USD. These fixed examples do not change with your calculator preferences.

Using the Loan & schedule example:

Loan amount ($)

250000

Annual interest rate (%)

6.5

Term (years)

30

Extra monthly payment ($)

0

First payment month

2026-11-01

Payment = P × r / [1−(1+r)^−n], where r is the monthly rate.

Example result

These are illustrative inputs. Change the values to explore a different scenario.

What to keep in mind

Assumes a fixed rate and no new borrowing or late fees.

Formula references

• CFPB: understanding mortgages (opens in a new tab)
• Investor.gov: financial tools and calculators (opens in a new tab)

References explain the underlying methods; they do not imply endorsement or individual professional review of Finflo.

Common questions