Credit Card Interest & Payoff Calculator

Why revolving fees feel invisible

Credit card friction rarely arrives as a single closing-cost invoice. It accrues month by month when balances carry past the grace period.

Minimum-payment formulas often cover interest plus a thin principal slice. Balances can last years while new purchases refill the bucket — the classic revolving drag this tool makes visible.

How to use this calculator

Enter balance and APR, then compare the illustrated minimum path with a fixed monthly amount you can sustain. Treat the run as a clean payoff: stop new purchases for the scenario to mean anything.

If you hold a promotional APR, use the rate that will actually apply across the payoff window — or run two scenarios (promo then go-to rate).

Worked example

A $6,500 balance at 22.9% APR with a simplified minimum near “interest + ~1–2% of principal” can stretch for years and produce four-figure interest. Raising to a fixed $350 per month typically compresses payoff into a much shorter window and cuts total interest sharply — even though month-one cash feels harder.

If the same cardholder only pays $150 while adding $100 of new spend monthly, the “payoff” never arrives. Behavior risk dominates formula tweaks.

Avalanche logic still applies across multiple cards: highest APR first when cash is fungible. Use the debt avalanche guide alongside this calculator when you hold more than one revolving balance.

Behavior risk

Payoff math fails if new purchases refill the balance. Model a clean runoff first, then add realism.

Penalty APRs, cash-advance pricing, and deferred-interest promotions change outcomes — re-run when the contract rate changes.

Assumptions

• Single balance, single APR, no new purchases during the modeled payoff.
• Minimum path is a simplified illustration, not every issuer’s exact formula.
• Monthly compounding approximation using APR/12.
• No penalty APR, deferred interest, or cash-advance pricing unless you change inputs.
• Educational scenario — not an issuer payoff plan or credit counseling.

Related guides

Deeper explainers that sit behind this calculator’s math:

• Credit Card Interest Drag: How Minimum Payments Stretch Balances — Why minimum payments keep balances alive — and how a fixed payoff plan changes total interest.
• Debt Avalanche Basics: Paying High-APR Balances First — An educational primer on avalanche vs snowball — and how payoff calculators support either plan.