Guide
How is credit card interest calculated monthly? (2026)
Published by Pikt. Published . Updated .
Credit card interest is usually a daily rate times your average daily balance times the days in the billing cycle. The daily rate comes from your APR. Pay the statement balance in full by the due date and you usually keep the grace period. Pikt names which card to use when you spend. It does not set your APR.
Quick decision table
| Card | Best for | Earn rate | Annual fee |
|---|---|---|---|
| APR | Starting point | Annual percentage rate | — |
| Daily rate | APR ÷ 365 (typical) | Per card agreement | — |
| Average daily balance | Common issuer method | × days in cycle | — |
Why the answer varies
The likely winner depends on the cards a person carries, the merchant category, active bonus categories and offers, reward values, earnings caps, known fees, and issuer terms. Card acceptance can also remove an otherwise higher-earning option. A public guide is a general comparison until a user provides their own wallet.
Pikt personalizes each estimate to the cards you already carry, the purchase details, and any reward values you set. It compares supported earn rates, eligible offers, caps, and card constraints, then explains the result. Use Card Check for a recommendation based on the cards you carry.
Why the usual card can earn less
People shop for earn rates and ignore interest. Interest can wipe out rewards if you carry a balance. This page is education, not advice about your APR.
How Pikt compares your cards
Enter the store and amount. Pikt estimates which card in your wallet is likely to earn the most, with the dollar difference and a short reason. Issuers decide. Online, Pikt Checkout names that pick before you click pay. On recurring bills, Subscriptions shows which card is likely to earn the most and how to put it on file. Coming next: Pikt Signal will put your best card on your lock screen when you're ready to pay in stores. Pikt helps you pick a card at checkout. It does not calculate or charge interest on your statement.
Frequently asked questions
- Is interest charged if I pay in full?
- Usually not, if you pay the statement balance by the due date and keep the grace period. Your card agreement is the source of truth.
- How do I estimate one month of interest?
- Daily rate × average daily balance × days in the cycle. Don't treat a blog example as your bill.
Methodology and disclosure
This guide uses Pikt's maintained rewards data and explains the conditions behind its comparison. Read the full methodology and corrections policy. Pikt estimates rewards; issuer terms and final rewards apply.
See which of your cards may earn the most for your next purchase.
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