How we calculate · Credit card payoff

How the credit card payoff calculator works

Clear formulas and limits for learning estimates—not statement disclosures or advice.

Written & maintained by John Rey Balais Developer · Nestfigure

Tool: Credit card payoff calculator · Embed: Embeddable calculator · All how-we-calculate pages · Payoff questions

Purpose

The calculator estimates how long a single credit card balance may take to clear and how much interest might accrue under a payment plan you type in. It is for education. It is not your issuer’s statement, a Truth in Lending disclosure, or personalized credit advice.

Core model

Monthly interest rate r = APR ÷ 100 ÷ 12.
Each month: interest ≈ starting balance × r.
Principal applied = payment − interest (last payment can be smaller).
Ending balance = starting balance − principal.
Repeat until balance is effectively zero, or stop with a clear error if the plan never pays off.

The Consumer Financial Protection Bureau explains that card issuers often calculate interest with methods such as daily accrual. Our monthly simplification is for transparent learning, not a claim that every issuer uses this exact method. CFPB Ask — interest calculation.

Payment modes

Fixed monthly payment

You enter a constant dollar amount each month. The schedule uses that amount until the balance clears.

Target months

You enter how many months you want. We solve for a constant payment using the standard amortization formula when APR > 0, or balance ÷ months when APR is 0. Then we run the same monthly schedule.

Simple minimum-style model

Each month’s payment = the greater of a floor ($) or a percent of the remaining balance. This is not your card’s real minimum formula. Real minimums are issuer-specific.

Outputs

Months (and years) to pay off
Monthly payment used or required
Total interest and total paid
Month-by-month schedule (UI shows early months; PDF can include full rows)
Compare table of nearby fixed payments

What we intentionally leave out

New purchases, cash advances, balance transfers, and fees
Multiple APRs or promotional / deferred-interest plans
Issuer-specific minimum payment formulas
Late fees, penalty APR, credit scores, or utilization advice
Debt counseling recommendations or “best card” lists

Official context (not Nestfigure math)

CFPB materials explain minimum payments, interest, and the statement box that estimates payoff if you pay only the minimum or a 36-month amount. Those are issuer/statement topics; Nestfigure is a separate educational model.