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Credit Card Interest Calculator

Tool

Calculate the monthly interest a credit card balance accrues at a given APR.

Your balance

What you carry past the due date, and at what rate.

Cost of carrying
$52.06 / month
What this balance costs you
Per day
$1.71
accrues daily on the balance
Per month
$52.06
added to your next statement
Over a full year
$625
if the balance never moves

Every $1,000 of balance at 24.99% costs about $20.83 a month. Card interest compounds daily on the average daily balance, so the real charge depends on how the balance moves through the billing cycle. Treat these numbers as a close approximation.

Pay the full statement balance by the due date and the number drops to $0. The grace period only survives while you pay in full every month.

A late payment can trigger a penalty APR, often 29.99% or higher, and it can apply to your existing balance. Rewards never outrun interest. Carrying a balance on a rewards card costs more than the points are worth.

How credit card interest actually accrues

Card interest compounds daily. The issuer divides your APR by 365 to get a daily rate, multiplies it by each day's balance, and sums the result over the billing cycle. A 24.99% APR works out to about 0.068% per day, which sounds harmless until it lands on a few thousand dollars for thirty straight days.

The calculator approximates the monthly charge as balance times APR divided by twelve, which tracks the issuer's daily math closely for a stable balance. A balance that swings during the cycle is charged on the average daily figure, so a mid-cycle payment cuts interest immediately rather than at the due date.

The grace period is the whole game

Pay the full statement balance by the due date and purchases accrue zero interest, no matter the APR. That grace period is why a 29.99% APR card costs a full-balance payer nothing. Carry even one dollar past the due date and most issuers revoke the grace period entirely, charging interest on new purchases from the day they post until you pay in full again.

This is also why APR should not drive card choice for people who never carry a balance, and should drive it almost exclusively for people who do. A rewards card earning 2% while charging 25% on a carried balance loses money eleven months out of twelve.

FAQ

Frequently asked questions

How much interest will I pay on a $1,000 credit card balance?
About $20.83 a month at 24.99% APR, roughly $0.68 a day. Hold it a full year while only covering the interest and you pay about $250. The same balance at a 0% intro APR costs nothing until the promotional window ends.
Is credit card interest charged monthly or daily?
Daily, billed monthly. Issuers apply a daily periodic rate (APR divided by 365) to your average daily balance, then post the total as a finance charge on your statement. Daily compounding means your effective annual rate runs slightly above the stated APR.
What is a good APR for a credit card?
In mid-2026, anything below about 21% is better than the typical new-card rate, which sits near 24% to 25%. Rewards cards cluster at 20% to 29% regardless of quality, because issuers price them for people who carry balances. If you pay in full monthly, the APR is irrelevant. If you carry a balance, rate beats rewards every time.
How do I avoid paying credit card interest entirely?
Pay the statement balance in full by the due date every month. The grace period then covers every purchase, indefinitely, at any APR. Autopay set to the statement balance makes this automatic. The only interest a full-balance payer ever sees comes from cash advances, which accrue from day one with no grace period.
Why am I charged interest after paying my full balance?
Usually trailing interest, also called residual interest. It accrues between the statement date and the day your payment arrived, and posts on the next statement. It appears after a month in which you carried a balance and then paid in full. One more full payment, made promptly, clears it and restores the grace period.

Written by the CreditCardSignups editorial team. Card rates and offers verified June 10, 2026. Point valuations updated 2026-06-10. Card terms change often, so confirm details on the issuer's site before applying.