Credit Card Interest Cost Calculator

What interest actually costs you

Credit card APRs are astronomical compared to almost any other debt. A 24% credit card charges more interest in one year than most mortgages charge in six. On a $5,000 balance at 24% APR, carrying the balance for 12 months with no payments costs $1,200 in pure interest — a quarter of the original debt.

The calculator above shows month-by-month what your specific balance, APR, and payment plan add up to in total interest. Play with the payment amount — doubling your monthly payment typically cuts total interest by 60–70%.

The daily compounding truth

Interest on credit cards compounds daily. That means the interest you accrue on day 1 becomes part of the balance on which day 2's interest is calculated. Over a year, a flat 24% APR effectively becomes about 27% compounded — you pay interest on your interest every single day.

This is why minimum payments keep people in debt for decades. If you're paying $50 a month on a $5,000 balance at 24%, the interest alone is ~$100/month — your payment isn't even covering the interest. Balance grows every month despite making payments. See our minimum payment calculator for the exact horror.

How to kill interest fast

Balance transfer. Move the balance to a 0% intro APR card for 12–21 months and pay it down with zero interest accumulating. 3–5% transfer fee, but usually saves thousands. See best balance transfer cards.

Avalanche method. Pay minimums on all cards, throw everything extra at the highest-APR card first. Mathematically optimal — minimizes total interest paid.

Snowball method. Pay minimums, throw extra at the smallest balance first. Mathematically suboptimal but psychologically effective — quick wins keep people motivated.

Personal loan consolidation. Fixed-rate loan (10–18% APR) replaces variable-rate card debt. Good when card APR is 24%+ and balance is $5k+.

APR reduction request. Free phone call. 30–50% success rate.

The true hourly cost of carrying a balance

A $5,000 balance at 24% APR costs roughly $100/month in interest — about $3.30/day, or $0.14/hour. On a $10,000 balance at 24%: $200/month, $6.60/day, $0.28/hour. If that feels small, remember: you're paying that hourly rate while you sleep, while you work, while you shop. It never stops until the balance is zero.

Perspective helps. Someone earning $25/hour post-tax keeps about $25/hour of productive income. Carrying a $15,000 balance at 24% loses $0.41/hour to interest — that's 1.6% of their effective wage gone to the credit card company, 24 hours a day.

When interest is acceptable (rarely)

Three scenarios where carrying a balance short-term can be OK: (1) a planned purchase during a legitimate 0% intro APR window (pay it off before the window ends); (2) a one-month emergency you'll pay next month; (3) a small balance under $100 where the math doesn't justify the effort.

Everything else is a red flag. Carrying balances chronically is the single most expensive financial mistake most households make — costing the average cardholder $1,000+ per year in avoidable interest. If you've been revolving for 6+ months, stop reading and go run the payoff plan calculator now.

Pro tips

• Always pay on statement <em>balance</em>, not minimum payment.

• Set autopay for full statement balance the day it posts.

• Charge only what you can pay off this month.

• Negotiate APR once a year — $30 of phone time is worth $200+ in savings.

• If you&apos;re drowning, call a nonprofit NFCC-accredited credit counselor (nfcc.org) before you miss payments.