What Is Credit Card Interest?
Credit card interest is the charge a bank adds when you do not pay your full statement balance by the due date. It is quoted as a monthly rate and applies to the balance you carry forward.
Banks also call it a finance charge. It only applies to revolving credit, where you pay part of the bill and roll the rest into the next month.
Pay the full statement balance every month and you pay no interest on purchases at all. Carry any amount forward and interest applies, plus 18% GST on that interest.
How Credit Card Interest Works in India
Credit card interest works on the unpaid balance, charged daily at the monthly rate and billed once a month. Three rules decide how much you pay.
- Interest-free period only when paid in full: The 20 to 50 day interest-free window applies only if you clear the whole statement by the due date.
- Interest from the transaction date: Once you carry a balance, most issuers charge interest from the date of each purchase, and new purchases lose the interest-free period too.
- GST on top: Interest and other card charges attract 18% GST, which appears as a separate line on your statement.
This calculator models the monthly effect: interest on the balance you carry, GST on that interest, and the payment you make each month.
Credit Card Interest Formula: How to Calculate It
To calculate credit card interest, multiply the balance you carry by the monthly interest rate, then add 18% GST on that interest. For a daily figure, convert the monthly rate to a daily one.
Monthly interest = Balance × Monthly rate
GST = Monthly interest × 18%
Daily rate = Monthly rate × 12 ÷ 365
Interest per day = Balance × Daily rate
APR = Monthly rate × 12| Term | What It Means |
|---|---|
| Balance | What you carry past the due date. With daily interest, it is the average daily balance over the cycle. |
| Monthly rate | The finance charge printed in your card’s Most Important Terms and Conditions (MITC). |
| GST | 18% on the interest amount, not on the balance itself. |
| Minimum due | The smallest payment that keeps your account current. It does not stop interest. |
Worked Example: Interest on a Rs 1 Lakh Balance
Take a Rs 1,00,000 balance at 3.5% a month, the calculator's default. One month of interest is 1,00,000 × 3.5% = Rs 3,500.
GST at 18% adds Rs 630, so the month's charges come to Rs 4,130. Your total due becomes Rs 1,04,130.
| Item | Amount |
|---|---|
| Balance carried forward | Rs 1,00,000 |
| Interest at 3.5% | Rs 3,500 |
| GST at 18% on interest | Rs 630 |
| Total due | Rs 1,04,130 |
| Minimum due at 5% of total | Rs 5,206.50 |
| Part of that payment that cuts the balance | Rs 1,076.50 |
Of a Rs 5,206.50 minimum payment, Rs 4,130 goes to interest and GST. Only about a fifth of the payment reduces what you owe.
Average Daily Balance Method, Step by Step
Because interest accrues daily, the exact charge for a cycle depends on your balance each day. The average daily balance method adds those daily balances and divides by the days in the cycle.
| Days | What Happened | Daily Balance |
|---|---|---|
| Days 1 to 10 | Rs 50,000 carried from the last statement | Rs 50,000 |
| Days 11 to 20 | Rs 20,000 paid on day 11 | Rs 30,000 |
| Days 21 to 30 | Rs 10,000 new purchase on day 21 | Rs 40,000 |
| Average daily balance | (10 × 50,000 + 10 × 30,000 + 10 × 40,000) ÷ 30 | Rs 40,000 |
Interest for the cycle is Rs 40,000 × 0.115% × 30 days, about Rs 1,380.82. GST adds Rs 248.55, for about Rs 1,629 in total.
Paying part of the bill early in the cycle lowers the average, which is why a payment on day 11 costs less interest than the same payment on day 29.
Monthly Rate vs APR vs Effective Annual Rate
Indian card issuers quote a monthly rate. The APR multiplies it by 12. The effective annual rate adds compounding, because unpaid interest itself attracts interest the next month.
| Monthly Rate | APR | Effective Annual | Effective with GST |
|---|---|---|---|
| 2.50% | 30.0% | 34.5% | 41.7% |
| 3.00% | 36.0% | 42.6% | 51.8% |
| 3.50% | 42.0% | 51.1% | 62.5% |
| 3.75% | 45.0% | 55.5% | 68.1% |
Typical Indian card rates run from about 2.5% to 3.75% a month, roughly 30% to 45% a year. Your exact rate is in your card's MITC and on your statement.
A balance left untouched at 3.5% a month with GST grows by 62.5% in a year. That is the true cost of revolving, and why APR alone understates it.
How Much Interest Will You Pay on Your Balance?
At 3.5% a month, each Rs 1 lakh you carry costs Rs 3,500 in interest and Rs 4,130 with GST, every month it stays unpaid. The table scales that to common balances.
| Balance | Interest per Month | With GST | Per Day with GST |
|---|---|---|---|
| Rs 25,000 | Rs 875 | Rs 1,033 | Rs 34 |
| Rs 50,000 | Rs 1,750 | Rs 2,065 | Rs 68 |
| Rs 1,00,000 | Rs 3,500 | Rs 4,130 | Rs 136 |
| Rs 2,00,000 | Rs 7,000 | Rs 8,260 | Rs 272 |
| Rs 5,00,000 | Rs 17,500 | Rs 20,650 | Rs 679 |
The input panel above shows the same monthly and per-day figures for your own balance and rate.
The Minimum Payment Trap
Paying only the minimum due keeps your account current but clears the balance extremely slowly, because most of each payment goes to interest and GST.
| How the Minimum Is Set | First Payment | Time to Clear | Interest + GST |
|---|---|---|---|
| 5% of total due | Rs 5,207 | 28 yr 5 mo | Rs 3,72,861 |
| All interest and GST + 2% of balance | Rs 6,130 | 16 yr 6 mo | Rs 2,02,035 |
| All interest and GST + 5% of balance | Rs 9,130 | 7 yr 6 mo | Rs 81,576 |
Issuers set the minimum differently. Some use 5% of the total due; SBI Card, for example, charges all interest, GST and fees plus 2% of the remaining balance. Your statement shows which applies.
Under a 5% minimum, a Rs 1 lakh balance costs more than three times its size in interest and GST before it is gone. The minimum payment shrinks as the balance falls, which is what stretches it out.
Choose your card's rule under More settings to see the trap for your own balance.
Credit Card EMI Calculator
See what converting a large card balance into fixed EMIs would cost instead.
How Much Should You Pay to Clear Your Card?
To clear a card balance by a set date, pay the fixed amount that covers each month's interest and GST and still cuts the balance. Pick a plan below or use "Pay by date" in the calculator.
| Clear In | Monthly Payment | Interest + GST | Total Paid |
|---|---|---|---|
| 6 months | Rs 19,157 | Rs 14,942 | Rs 1,14,942 |
| 12 months | Rs 10,736 | Rs 28,829 | Rs 1,28,829 |
| 18 months | Rs 7,983 | Rs 43,694 | Rs 1,43,694 |
| 24 months | Rs 6,646 | Rs 59,510 | Rs 1,59,510 |
| 36 months | Rs 5,384 | Rs 93,834 | Rs 1,93,834 |
The 36-month payment of Rs 5,384 is barely more than the first 5% minimum of Rs 5,207. Keeping the payment fixed instead of letting it shrink cuts 25 years off the plan.
Fixed monthly payments
| Monthly Payment | Time to Clear | Interest + GST |
|---|---|---|
| Rs 5,000 | 44 months | Rs 1,16,066 |
| Rs 10,000 | 14 months | Rs 31,664 |
| Rs 15,000 | 8 months | Rs 19,376 |
| Rs 20,000 | 6 months | Rs 14,390 |
A Rs 5,000 payment barely clears the Rs 4,130 of first-month charges, so the balance moves slowly and interest ends up larger than the debt.
Card Interest vs EMI Conversion vs a Personal Loan
Revolving interest is usually the most expensive way to carry a card balance. EMI conversion and a personal loan both replace it with a fixed rate and a fixed end date.
| Factor | Revolving Interest | Card EMI Conversion | Personal Loan |
|---|---|---|---|
| Rate | Card finance charge, often 30% to 45% a year | Disclosed when you convert, usually lower | Set by the lender on your profile |
| End date | None, depends on what you pay | Fixed tenure | Fixed tenure |
| Extra costs | 18% GST on interest | Processing fee plus GST | Processing fee plus GST |
| Card limit | Balance uses your limit | Converted amount stays blocked | Card limit freed once repaid |
To price a conversion, the Credit Card EMI Calculator shows the EMI, interest and fees for a chosen tenure.
To compare a loan offer, the Personal Loan Calculator gives the EMI and total interest at the rate you are quoted.
Cash Withdrawals on a Credit Card
Cash withdrawn on a credit card is charged interest from the day you take it out. There is no interest-free period on cash, even if you usually pay in full.
Most issuers also charge a cash advance fee on each withdrawal, and GST applies to that fee. Check the cash advance rate and fee in your card's MITC.
To see the interest on a cash withdrawal, enter the amount as the balance here and set the rate to your card's cash advance rate.
RBI Rules on Card Interest, Minimum Due and Late Fees
The RBI's Credit Card and Debit Card Directions, 2022 limit how issuers can charge you when you do not pay in full.
- No negative amortization: The minimum amount due must be set so that paying it does not make your balance grow.
- No interest on unpaid charges: Unpaid charges, levies and taxes cannot be capitalised to charge or compound interest on them.
- Three-day grace before late fees: Late payment charges apply, and the account is reported past due, only when payment is more than three days late.
- Late fees on the unpaid amount: Late charges are levied on the amount still outstanding after the due date, not the whole bill.
- Minimum due explained: Issuers must tell you what paying only the minimum amount due means for you.
The grace period only stops a late fee. Interest still applies to any unpaid balance, so the only way to avoid it is to pay the full statement balance on time.
How to Reduce Credit Card Interest
You reduce credit card interest by carrying a smaller balance for fewer days. These steps work from quickest to longest.
- Pay the full statement balance: It is the only way to keep the interest-free period and pay no interest on purchases.
- Pay more than the minimum, and keep it fixed: A payment that does not shrink with the balance clears it far sooner.
- Pay early in the cycle: Under daily interest, a payment on day 5 cuts more interest than the same payment on day 25.
- Stop new spending on the card: New purchases on a revolving card start costing interest from the day you make them.
- Move the balance to a cheaper rate: EMI conversion, a balance transfer or a personal loan can replace the card rate.
- Clear the costliest card first: With several cards, focus spare money on one at a time.
For step 5, the Balance Transfer Savings Calculator shows the net saving after transfer fees.
For step 6, the Debt Snowball Calculator builds a month-by-month plan across all your cards and loans.
A lower balance also lowers your utilization. The Credit Utilization Calculator shows your ratio per card and overall.
Debt Snowball Calculator
Several cards carrying balances? Get a payoff order and a debt-free date.
Common Credit Card Interest Mistakes
Most people overpay on card interest because of a few habits, not one big decision.
- Treating the minimum due as the bill: It avoids a late fee, not interest.
- Paying almost all of the bill: Leaving even a small amount unpaid can cost the interest-free period on new purchases.
- Comparing a monthly rate with an annual one: 3.5% a month is 42% a year before compounding and GST.
- Forgetting GST: 18% GST on interest raises the real monthly charge from 3.5% to 4.13%.
- Withdrawing cash on the card: Interest starts on day one, with a fee on top.
- Letting the payment shrink: Paying whatever the minimum says each month stretches the debt out for years.
Limitations of This Calculator
This credit card interest calculator gives a close planning estimate. Your statement can differ for these reasons.
Monthly, not daily, interest. Banks charge interest daily on the running balance. The monthly model here is close but not identical, especially when payments land mid-cycle.
No new spending. The plan assumes you stop using the card. Any new purchase adds to the balance and the interest.
Constant rate. Issuers can change the rate on your card. The calculator holds it steady for the whole plan.
Fees left out. Late fees, annual fees and cash advance fees are not included. Only interest and GST on interest are.
How to Use This Credit Card Interest Calculator
Using the credit card interest calculator takes about a minute with your latest statement.
- Enter your balance and rate: Use the outstanding balance and the monthly interest rate from your statement.
- Read this month's charges: The box under the rate shows interest with GST for this month, per day and as an APR.
- Pick a repayment plan: Choose minimum due, a fixed monthly payment, or a payoff date in months.
- Match your card's rules: Open More settings to set how your minimum due works and whether GST is included.
- Open the Payoff Schedule: Compare plans side by side and see where each payment goes.
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Frequently Asked Questions
Disclaimer: All calculations on this page are indicative only and based on the inputs you enter. Actual credit card interest depends on your issuer's billing cycle, daily interest method, minimum due rule, fees and any rate changes. Rates quoted are general market ranges; check your card's MITC and statement for exact figures. This calculator is for educational and planning purposes only and does not constitute financial advice.