Credit Card Interest Calculator
Estimate daily and monthly credit card interest from your balance and APR, add an optional statement-cycle estimate using average daily balance, and see how much interest may build before the balance is paid off.
Your numbers
Example loaded: $7,500 balance, 22% APR, and a $225 monthly payment. Replace the example numbers to calculate your own estimate.
How this calculator works
This calculator estimates daily interest with APR ÷ 365 and first-month interest with APR ÷ 12. It then models how the balance changes with the monthly payment and optional extra monthly payment.
If you turn on the statement-cycle estimate, it also uses average daily balance, billing-cycle length, and your selected 365- or 360-day convention to estimate interest for that statement cycle. If your statement doesn’t show an average daily balance, the optional helper can estimate it from a starting balance plus purchases, payments, and credits entered by posted date.
The results show a daily planning estimate, estimated first-month interest, an optional statement-cycle estimate, a simple one-year snapshot, total interest until payoff, total paid, payoff date, and the share of the next payment going to interest.
For more explanation of APR, daily and monthly interest, and payment pressure, use the credit card interest guides.
Results
Interest impact
Statement-cycle estimate
Next payment breakdown
Payoff outcome
Total paid breakdown
- The daily interest snapshot uses the starting balance and APR ÷ 365.
- The optional statement-cycle estimate uses average daily balance × (APR ÷ 365 or 360) × billing-cycle days. Choose the convention used by your issuer when you know it. See the CFPB explanation of common credit card interest calculations.
- If you use the average daily balance helper, it starts with the beginning balance, applies each entered purchase, payment, or credit on its posted date, adds the modeled daily balances, and divides that total by the billing-cycle length. If your statement already provides an average daily balance, use the statement figure.
- The payoff model accrues interest monthly using APR ÷ 12.
- Loaded example: $7,500 × 22% ÷ 12 = $137.50 in estimated first-month interest.
- Payments are modeled once at the end of each month.
- Interest charged before your next payment is an estimate based on the starting balance and APR.
- The note below the monthly payment field may flag payments that are close to a typical minimum-payment level. Actual issuer minimum-payment rules vary.
- The simple one-year interest estimate assumes the same balance is carried for the full year.
- Total interest until payoff is based on your entered monthly payment and optional extra monthly payment.
- The total paid breakdown separates the original balance from estimated interest so you can see how much of the projected repayment is borrowing cost.
- The payment breakdown shows an estimate of how much of your next payment goes to interest versus principal.
- No late fees, annual fees, promotional rates, penalty APR changes, grace-period effects, new purchases, or issuer-specific transaction timing are included.
How the statement-cycle estimate works
Credit card issuers commonly calculate interest from balances carried during the billing cycle. If your statement provides an average daily balance, you can use that figure with the cycle length to get a closer estimate of the interest charge for that period.
The calculator uses average daily balance × daily periodic rate × billing-cycle days. The daily periodic rate is APR ÷ 365 by default, with APR ÷ 360 available for cards that use that convention. Purchases, payments, credits, grace periods, promotional rates, and issuer-specific rules can still make the actual statement charge different.
If you don’t know the average daily balance, open the helper and enter the starting balance for the cycle plus any purchases, payments, or credits by posted date. The helper treats each entered change as affecting that day’s balance, totals the modeled daily balances, and divides by the number of days in the cycle. Use the average daily balance printed on your statement when it’s available, since the issuer’s own figure reflects its posting rules and account details.
How to read your interest result
Read the result in three steps. Start with the current interest charge, check how the next payment splits between interest and principal, and then review the total payoff cost. That sequence shows both what the balance is costing now and what could happen if the payment stays unchanged.
Current interest charge
The daily and monthly estimates show the immediate cost of carrying the current balance. They are snapshots, not predictions that the balance will remain unchanged.
Next payment split
The interest share shows how much of the next payment covers borrowing cost. The principal portion is the amount that lowers the balance.
Total payoff cost
Total interest and payoff time show the longer-term effect of the entered payment. A long payoff gives interest more billing cycles in which to accumulate.
If interest takes a large share of the next payment and the payoff still lasts for years, the payment may be reducing the balance too slowly. If most of the payment reaches principal and the payoff time is manageable, the current plan may already be doing useful work.
Should you raise the payment or lower the APR?
The better first test depends on what's creating the cost. Compare the change in total interest and payoff time, not just the new monthly payment.
Raise the regular payment
Start here when the balance is falling but the payoff still takes longer or costs more than you want. A larger fixed payment reduces principal sooner without changing accounts.
Test an extra monthly amount
Use the Extra Payment Calculator when a smaller recurring increase may be sustainable. Compare both the time saved and the interest saved.
Compare a lower rate
Use the Balance Transfer Savings Calculator when a promotional offer is available. Keep the same total monthly payment, then compare the transfer fee, promotional period, post-promotional APR, and total cost. The When a Balance Transfer Saves Money guide explains how to interpret the result.
Credit card interest calculator FAQ
Is credit card interest calculated daily or monthly?
Many credit cards use a daily periodic rate and balances carried during the billing cycle to calculate interest. This tool shows both a simple monthly planning estimate and an optional statement-cycle estimate so you can compare the two views.
Why can the statement estimate differ from the monthly estimate?
The monthly estimate uses the current balance and APR ÷ 12. The statement estimate uses average daily balance, the actual number of days entered for the billing cycle, and APR ÷ 365 or 360. A changing balance or a longer or shorter cycle can move the statement estimate above or below the monthly estimate.
What is average daily balance?
Average daily balance is the average of the balances carried across the days in a billing cycle. If your statement provides it, use that figure. If it doesn’t, the helper above can estimate the average from a starting balance and dated purchases, payments, or credits.
Can paying earlier in the billing cycle reduce interest?
When interest is accruing on a carried balance, an earlier posted payment can reduce the balance used on more days of the cycle. The exact effect depends on the card’s posting rules, grace period, APR categories, and other account terms.
Can one credit card have more than one APR?
Yes. Purchases, balance transfers, cash advances, promotional balances, and penalty-rate balances can have different APRs. This calculator models one APR at a time, so use the rate that applies to the balance you’re estimating and check the card agreement when multiple rate categories are present.
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Learn more about credit card interest
These guides explain how credit card interest builds over time, how repayment speed affects total borrowing cost, and why minimum payments can dramatically extend repayment.