Credit card interest calculator
What your balance costs you each day, month and year at your APR, and how the issuer actually works it out.
Interest per month
$70.00
How your statement interest is worked out
Card issuers don’t charge interest on your statement balance. They charge it on the average daily balance. Move the purchase and payment days to see why timing matters.
- Add up the balance at the end of each of the 30 days, divide by 30: $2,126.67 average daily balance.
- Daily periodic rate = 24% ÷ 365 = 0.0658% a day.
- $2,126.67 × 0.0658% × 30 days = $41.95 interest this cycle.
Paying on day 1 instead of day 20 would make this cycle’s interest $31.96. Paying earlier in the cycle lowers every day’s balance after it.
Monthly interest by balance and APR
| Balance | 18% APR | 21% APR | 24% APR | 27% APR | 30% APR |
|---|---|---|---|---|---|
| $500 | $7.50 | $8.75 | $10.00 | $11.25 | $12.50 |
| $1,000 | $15.00 | $17.50 | $20.00 | $22.50 | $25.00 |
| $2,500 | $37.50 | $43.75 | $50.00 | $56.25 | $62.50 |
| $5,000 | $75.00 | $87.50 | $100.00 | $112.50 | $125.00 |
| $10,000 | $150.00 | $175.00 | $200.00 | $225.00 | $250.00 |
| $20,000 | $300.00 | $350.00 | $400.00 | $450.00 | $500.00 |
Balance × APR ÷ 12. Actual charges vary a little with the days in each billing cycle.
Cutting the interest you pay
- Pay earlier in the cycle, or split your payment in two. The explainer above shows why it lowers the average daily balance.
- Pay more than the minimum. See how long the minimum takes with the minimum payment calculator.
- Move the balance to a lower rate: check the balance transfer calculator.
- Make a payoff plan. The credit card payoff calculator gives you a date.
Questions people ask
How is credit card interest calculated?
Most US card issuers use the average daily balance method. They take your balance at the end of each day in the billing cycle, average it, multiply by the daily periodic rate (APR ÷ 365, some issuers use 360) and by the number of days in the cycle. The explainer on this page walks through it with your own APR.
How much interest will I pay on $5,000 at 24% APR?
About $100 a month (5,000 × 24% ÷ 12), or around $3.29 a day. If you carried the full $5,000 for a year without paying it down, compounding would bring it to about $1,341.
Do I pay interest if I pay the full statement balance?
Usually not. Most cards give a grace period on purchases: if you pay the full statement balance by the due date, no purchase interest is charged. Carry any balance and you typically lose the grace period, so interest starts on new purchases too, until you pay in full again.
What is the difference between APR and APY on a credit card?
APR is the yearly rate before compounding. Because interest is compounded (added to the balance and then charged interest itself), the effective yearly cost is a bit higher. At 24% APR compounded monthly, the effective rate is about 26.8%.
Why did my interest charge change when my balance didn’t?
Billing cycles have different numbers of days (28 to 31), and the timing of purchases and payments inside the cycle changes the average daily balance. A variable APR tied to the prime rate can also move.