Credit Card Interest Calculator

Understanding what a balance really costs

Credit card interest is quietly one of the highest costs in personal finance. Because the rate is quoted as an APR — an annual figure — the day-to-day and month-to-month cost is easy to overlook. This calculator makes it concrete by breaking a single balance into the interest it accrues per day, per month and per year.

The core formula is simple: yearly interest = balance × APR ÷ 100. Divide that by 12 for the monthly cost, or by 365 for the daily cost. On a ₹1.5 lakh balance at 36% APR, that is roughly ₹54,000 a year, ₹4,500 a month, or about ₹148 every single day — accruing whether you think about it or not.

Why the rate is so high

Indian credit cards typically charge 30% to 45% per year, several times the rate on a home or personal loan. The reason is that card debt is unsecured and revolving: the issuer takes on more risk and, in exchange, charges a premium. On statements the rate is often shown as a monthly figure — say 3% — which sounds modest until you annualise it to 36%.

Worse, real cards compound monthly. Any interest you don't pay is added to the balance, so next month you pay interest on the interest. This calculator shows the base cost; on a card the effective cost creeps higher the longer a balance revolves.

The grace period is your best friend

The single most valuable feature of a credit card costs you nothing: the interest-free grace period. If you pay your full statement balance by the due date, regular purchases accrue no interest at all. You only start paying interest when you carry a balance forward — at which point the grace period disappears until you clear the balance in full again.

Cash advances are the exception: they usually carry a higher rate, a flat fee, and no grace period, so interest builds from the moment you withdraw. Treat them as a last resort.

Cutting the cost

If you already carry a balance, three moves reduce the interest fastest:

• Pay it down aggressively — every rupee off the balance directly lowers the daily interest.
• Convert to an EMI at 12–18%, roughly half the revolving rate.
• Transfer the balance to a card with a lower promotional rate, watching the fee and the post-promo rate.

Used as a cost-of-carry gauge, this calculator turns an abstract APR into a real rupee figure — and that clarity is usually all the motivation needed to pay a balance off sooner.