The Money Decoded

Calculators

Credit Card Interest Calculator

Educational content only, not financial advice

A credit card balance has two very different price tags depending on how fast you clear it. Enter your balance, your card's interest rate, and the amount you plan to pay each month, and the calculator shows how long that takes and what it costs, side by side with paying only the issuer minimum. It works in rupees, with the 18% GST that Indian statements add on the interest, or in dollars.

Currency

That is about 3.50% a month, the way Indian cards quote it. 18% GST is added on the interest.

What you plan to pay each month. The minimum-only card beside it recomputes the issuer minimum every month for comparison.

Your payment

₹6,000 a month

Debt-free in

11 months

Total interest
₹10,654
GST at 18%
₹1,918
Interest as a share of the balance
25%

Minimum only

The issuer minimum, every month

Debt-free in

16y 5m

Total interest
₹1,44,149
GST at 18%
₹25,947
Interest as a share of the balance
340%

The verdict

Paying ₹6,000 a month instead of the minimum clears the balance 15y 6m sooner and saves about ₹1,57,523 in interest and GST. On the minimum alone, the finance charge comes to about 340% of the original balance.

Interest is modelled monthly at the APR you enter, with the issuer minimum taken as the finance charge plus 1% of the balance (floor ₹500). In ₹ mode, 18% GST is added on the interest, the way Indian statements bill it. This is an educational estimate; your card's exact daily accrual, fees, and minimum formula will differ, so treat the figures as a close guide, not a statement.

How the calculator works

The calculator runs your balance forward month by month. Each month it adds one month of interest, calculated as the balance times the APR divided by 12, and in rupee mode it adds 18% GST on that interest, the way Indian issuers bill it. It then subtracts your payment and repeats until the balance reaches zero. The minimum-only column runs the same simulation but pays the issuer minimum each month, taken as the finance charge plus 1% of the balance, with a floor of ₹500 or $25. That is the real structure most cards use, and it is why the minimum clears a balance so slowly.

The headline figure worth watching is the interest as a share of the balance. On a high-rate card paid near the minimum, the interest can run to two or three times the amount you originally borrowed, which is the number that turns an abstract APR into something you can feel.

A worked example in rupees

Take the rupee default: a ₹50,000 balance at 42% a year, which is the 3.5% a month a typical Indian card charges. Pay ₹6,000 a month and the card clears in 11 months, costing about ₹10,654 in interest and ₹1,918 in GST, roughly 25% of the balance. Pay only the minimum and the same ₹50,000 takes about 16 years and costs around ₹1,44,000 in interest plus ₹26,000 in GST, near ₹1,70,000 in total. That is more than three times what you borrowed, and the difference between the two paths is about ₹1,57,000.

The same trap in dollars

Switch to dollars and the shape holds. A $5,000 balance at 24% APR paid at $200 a month clears in three years and costs about $2,001 in interest, around 40% of the balance. Paying only the minimum stretches the same debt to roughly 19 years and about $8,723 in interest, about 174% of what you borrowed. The extra dollars above the minimum are the whole story: they go almost entirely to principal, so each one shortens the timeline and cuts the interest that would have compounded on top of it.

The formula behind it

In the US, the monthly interest is the balance times the APR divided by 12, and issuers apply a daily version of it, the APR divided by 365, to your average daily balance. In India, cards quote a monthly rate instead, so a 3.5% monthly charge is about 42% a year, and 18% GST is added on the interest. Both models are built into the calculator, and both are covered in depth in how credit card interest works and APR vs interest rate.

Pair this calculator with the guides

For the mechanics behind these numbers, the grace period, daily compounding, and why the minimum is engineered to keep a balance revolving, read How Credit Card Interest Works. If you are juggling several balances rather than one, the debt snowball vs avalanche calculator compares the two payoff orders across all of them, and the loan calculator models any single balance as a fixed-payment loan across three tenures.

Frequently asked questions

How much interest will I pay on my credit card?

Roughly your balance times the APR divided by 12 each month, then repeated on whatever is left. A ₹50,000 balance at 42% a year is about ₹1,750 in interest in the first month, plus ₹315 of GST in India. A $5,000 balance at 24% is about $100 in the first month. The calculator above sums this month by month at your payment, so you see the full total rather than a single month, and the total is almost always a bigger share of the balance than people expect.

How long does it take to pay off a credit card paying only the minimum?

Far longer than most people guess, because the minimum is designed to barely dent the principal. A ₹50,000 balance at 42% paid at the issuer minimum takes about 16 years and costs roughly ₹1,70,000 in interest and GST, more than three times the original balance. A $5,000 balance at 24% takes about 19 years on the minimum and costs around $8,700 in interest. The calculator shows this beside your own payment so the gap is concrete.

How much do I save by paying more than the minimum?

The saving is usually enormous because interest stops compounding the moment the balance clears. On the ₹50,000 example, paying ₹6,000 a month instead of the minimum clears the card in 11 months and cuts the finance cost from about ₹1,70,000 to about ₹12,600, a saving near ₹1,57,000. On the $5,000 example, paying $200 a month saves roughly $6,700 versus the minimum. Enter your own numbers above to see your exact saving.

How is credit card interest calculated in India?

Indian issuers quote a monthly rate, commonly 3.5% to 3.75%, which annualizes to about 42% to 45% a year. Interest is charged on the outstanding from the transaction date once you carry a balance, using the formula (days times amount times monthly rate times 12) divided by 365, and 18% GST is added on the interest. This calculator applies the monthly rate and the 18% GST line in rupee mode, which most Indian tools leave out.

What counts as a realistic minimum payment?

Most issuers set the minimum as the greater of a floor (around ₹500 in India or $25 to $35 in the US) or the month's finance charge plus about 1% of the balance. That structure always covers the interest and shaves off a sliver of principal, which is exactly why it clears so slowly. This calculator uses that formula for the minimum-only column, so the payoff time is realistic rather than the impossible numbers a flat-percentage tool can show.

How do I avoid credit card interest entirely?

A normal purchase carries zero interest if the full statement balance is paid by the due date, because the grace period covers it. The moment any balance is carried, the grace period ends and interest runs daily on the balance, including on new purchases, until it is cleared. So the number that decides whether a card costs anything is the balance left unpaid when the statement closes, not the APR itself.

Sources