Credit Card Interest Cost Calculator
How much interest will you pay on your credit card? Enter your balance, APR, and the amount you pay each month. You'll see the total interest, your exact payoff date, and a full amortization table — plus how much you'd save by doubling your payment.
Paying $150.00 a month clears $5,000 in 4 years, 6 months — paid off by January 2031, with $8,045.29 paid in total.
Amortization table (year by year)
| Year | Paid | Interest | Principal | Balance |
|---|---|---|---|---|
| ▸ 2026 | $900 | $559 | $341 | $4,659 |
| ▸ 2027 | $1,800 | $989 | $811 | $3,848 |
| ▸ 2028 | $1,800 | $782 | $1,018 | $2,830 |
| ▸ 2029 | $1,800 | $521 | $1,279 | $1,551 |
| ▸ 2030 | $1,745 | $194 | $1,551 | $0 |
How credit card interest compounds daily
Your card's APR is an annual rate, but interest isn't charged once a year — it's charged every day. Almost every US issuer uses the average daily balance method: they take your APR, divide it by 365 to get a daily periodic rate, and apply that rate to your balance every single day of the billing cycle.
Work an example. A 22.99% APR divided by 365 is a daily rate of about 0.0630%. On a $5,000 balance that's roughly $3.15 of interest the first day. The next day's interest is charged on a slightly higher balance, and so on — interest compounding on interest. Over a 30-day cycle those daily charges sum to about $95, which is what lands on your statement.
Two things follow. First, because the rate compounds daily, your effective annual cost sits a little above the printed APR. Second, every dollar of principal you knock down early stops accruing interest for the rest of the cycle — which is why a bigger monthly payment saves more than it looks like it should. The full mechanics are laid out in how credit card interest works.
What paying just the minimum really costs
The monthly payment you enter above is a fixed amount — you pay the same dollar figure every month until the card is clear. A minimum paymentworks differently: it's a percentage of the balance (commonly 2%, with a $25 floor), so it shrinks every month as the balance shrinks. That single difference is the reason minimums are so expensive.
Because the minimum is a slice of a balance that's mostly interest at a 20-something percent APR, only a thin sliver touches principal — and as the balance falls, so does the payment, so progress slows to a crawl. A mid-four-figure balance paid at the minimum can take more than 20 years to clear and cost more in interest than you originally borrowed.
The fix is exactly what this calculator models: pick a fixed payment and hold it steady as the balance drops. For the full worked breakdown of why the minimum keeps you stuck, see the minimum payment trap, or run your own numbers through the minimum payment calculator.
How much you save by doubling your payment
The result box highlights this for your own numbers, but the pattern is worth understanding. Doubling a fixed payment does more than halve your payoff time — it cuts the total interest by more than half. That's because the balance spends far less time accruing interest, and the interest you do pay lands early, before it can compound.
On the default scenario — $5,000 at 22.99% APR — paying $150 a month takes about four and a half years and costs about $3,000 in interest. Double it to $300 and the balance clears in under two years for well under half that interest. The extra $150 a month isn't just paying down debt faster; it's buying you out of months of future interest charges.
If the numbers still feel steep, the other lever is the rate itself. Moving the balance to a 0% intro-APR card pauses interest entirely for the promo window — the balance transfer savings calculator checks whether the transfer fee is worth it against simply paying the balance down where it is. To map a target payoff date to the payment it requires, use the credit card payoff calculator.
Frequently asked questions
How much interest will I pay on my credit card?
It depends on your balance, your APR, and how much you pay each month. Enter those three numbers above and the calculator returns the exact total. As a benchmark, a $5,000 balance at 22.99% APR paid at $150 a month costs about $3,000 in interest and takes about four and a half years to clear. Because interest is charged on whatever you still owe, the larger your monthly payment, the less time the balance has to accrue interest — and the total cost drops fast.
How is credit card interest calculated?
Most US issuers use the daily balance method: they divide your APR by 365 to get a daily periodic rate, then apply that rate to your balance every day of the billing cycle and add up the daily charges at statement time. Because the rate compounds daily, the effective annual cost runs a little above the printed APR. This calculator compounds monthly, which lands within a dollar or two of the daily method for typical balances.
What counts as the APR I should enter?
Use the purchase APR from your statement or online account — that's the rate that applies to a carried balance. The average US credit card APR sits in the low-to-mid 20s, but yours could be anywhere from the mid-teens to over 30% depending on the card and your credit. If your card lists separate rates for purchases, balance transfers, and cash advances, use the one that matches the balance you're carrying.
How much does doubling my payment actually save?
A lot, because you cut the time the balance spends accruing interest roughly in half — and the interest saved is usually far more than half. The result box shows the exact figure for your numbers. On the $5,000-at-22.99% example, going from $150 to $300 a month cuts payoff from about 54 months to about 20 and saves well over $1,500 in interest. A fixed payment keeps attacking principal at full force, so every extra dollar compounds in your favor.
Does paying my balance in full each month avoid interest?
Yes — that's the grace period. If you pay your statement balance in full by the due date every month, most cards charge zero interest on purchases. Interest only starts once you carry a balance past the due date. This calculator is for when you're already carrying a balance and want to know what clearing it will cost.
Is this interest figure exact?
It's a close estimate for planning, not a billing statement. Real interest depends on your exact statement dates, when payments post, whether you make new purchases, and your issuer's compounding method. The calculator assumes a fixed balance with no new charges and a level monthly payment. Use it to size up the interest cost and see how payment size changes it, then confirm specifics against your own statement.
Related debt tools
How Credit Card Interest Works
The daily periodic rate, the grace period, and why carrying a balance is so corrosive.
Credit Card Payoff Calculator
Solve for a payoff date or a monthly payment and get the full month-by-month plan.
Minimum Payment Calculator
See what paying only the minimum costs — and how many years it stretches your payoff.
Balance Transfer Savings Calculator
Check whether moving the balance to a 0% intro card would beat paying it down where it is.
Estimates are educational only. The calculator assumes a fixed balance with no new purchases, a level monthly payment, and monthly compounding. Real interest depends on your statement dates, when payments post, and your issuer's compounding method — check your own statement for exact figures.