How is credit card interest calculated?

With monthly rate r = APR ÷ 12 and fixed payment P, months n = −log(1 − rB ÷ P) ÷ log(1 + r). Total paid = P × n; interest = Total Paid − Balance.

Why does my payment never pay off the card?

If your monthly payment is less than or equal to the first-month interest (Balance × APR ÷ 12), the balance never shrinks. Always pay more than that amount.

Do credit cards compound daily or monthly?

Most US issuers compound daily using a daily periodic rate (APR ÷ 365) on the average daily balance. This calculator uses monthly compounding for simplicity; results are typically within a few percent of real statements.

How can I pay off my credit card faster?

Increase the monthly payment, transfer the balance to a 0% intro-APR card (mind transfer fees), or consolidate into a lower-rate personal loan. Even an extra $50/month often cuts months and saves hundreds in interest.

Credit Card Interest Calculator

v1.3

Calculate credit card interest paid, payoff period, and total amount paid for any balance, APR, and monthly payment.

Last updated June 27, 2026 · Last reviewed June 16, 2026

Inputs

Credit card balance

USD

APR

Monthly payment

USD

Result

Estimated Interest Paid

$1,749.54

at 22% APR

Payoff Period2 yr 10 mo

Total Amount Paid$6,749.54

Saved calculations remain on this device unless you choose to share them. No tracking, no account needed.

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Formula

n = −log(1 − r·B ÷ P) ÷ log(1 + r) Total Paid = P × n Interest = Total Paid − B

How it works

A credit card interest calculator shows how long a balance takes to pay off and how much interest you'll pay at a given APR and monthly payment.

Example

Example: $5,000 balance at 22% APR with $200/month: r = 0.01833; n ≈ 33.7 months ≈ 2 yr 10 mo; interest ≈ $1,748.

Trust & Accuracy

Formula verified

Verified against standard mathematical and financial conventions.

Last reviewed

June 27, 2026

Accuracy tested

Edge cases tested, formula validation and manual verification completed.

Available for

United States, Canada, United Kingdom, Australia, India, European Union.

Currency support

USD · INR · CAD · AUD · GBP · EUR

Privacy

No information entered into this calculator is stored on our servers unless you explicitly choose to save or share your calculation.

Print, share & save

Use the Save, Share, Copy, PDF, CSV and Print actions under the result panel.

Accessibility

Keyboard navigable, screen-reader friendly labels, responsive on mobile and desktop.

Learn more: How we verify formulas · How we test accuracy · Methodology · Editorial policy

Recent Updates

We continuously review and improve our calculators to keep formulas, assumptions and references accurate.

View change log (4)Show

v1.3June 27, 2026
Added Trust & Accuracy panel and machine-readable change log.
v1.2June 20, 2026
Added Save, Share, PDF, CSV and Print actions to results.
v1.1June 10, 2026
Added global currency selector (USD, INR, CAD, AUD, GBP, EUR).
v1.0January 1, 2026
Initial calculator release with verified formulas and Official Sources.

Frequently Asked Questions

Disclaimer: Results are estimates for informational purposes only and should not be considered financial, medical, legal, or professional advice. Always consult a qualified professional before making decisions.