Credit card basics · Updated October 2026 · 6 min read
A credit card lets you spend now and pay later, and if you pay the full bill on time, it costs you nothing. If you don’t, interest charges build up fast. This guide explains how the billing cycle, due date and interest work, so you know exactly when you owe what.
In short: You get a bill once a month. If you pay the total amount due by the due date, you pay no interest. If you pay only part of it, you lose the interest-free period and start paying interest on your balance, often around 3–4% a month.
The basic idea
When you use a credit card, the bank pays the shop for you. The bank then collects that money from you later, through your monthly bill. Your card has a credit limit, which is the most you can owe at any time. For example, with a ₹1,00,000 limit, you can spend up to that amount before paying it back.
The billing cycle, statement date and due date
- Billing cycle: The period of about 30 days over which your purchases are added up.
- Statement date: The day your bill is generated, showing everything you spent in that cycle.
- Due date: The last day to pay without penalty. It is usually around 18–20 days after the statement date.
Example: Your statement date is the 5th of each month and your due date is the 25th. You spend ₹5,000 on 6th March, just after a statement. That purchase appears on your 5th April statement, and you have until 25th April to pay it. That is nearly 50 days of interest-free credit. If you spend on 4th March instead, it appears on the 5th March statement, and the due date is 25th March, which is only around 20 days.
Your statement date and due date are printed on your bill and in your bank’s app. Because the interest-free period depends on your statement date, timing big purchases just after it gives you more time to pay.
What is on your bill
| Item | What it means |
|---|---|
| Total amount due | Everything you owe for that statement. Pay this to avoid all interest. |
| Minimum amount due | The smallest payment that keeps your account in good standing. It is usually a small percentage of your balance, plus any fees and overdue amounts. |
| Due date | The last day to pay. Pay a day or two early to be safe. |
| Available credit limit | How much you can still spend. |
How interest works
If you pay the total amount due
You pay no interest at all. This is the best way to use a credit card.
If you pay less than the total
You lose the interest-free period on that bill. Interest is then charged on the unpaid balance, and often on new purchases as well, until you pay the full amount. Many Indian banks charge about 3–4% per month, which works out to roughly 36–48% a year. Check your card’s terms for the exact rate.
Example: You owe ₹20,000 and pay only the minimum of ₹1,000. The remaining ₹19,000 attracts interest at, say, 3.5% a month, which is about ₹665 for the month. Add a late fee if you were late, and GST on the charges, and the cost of the unpaid balance climbs quickly.
If you miss the due date
Besides interest, the bank may charge a late payment fee, which usually depends on how much you owe. A missed payment can also be reported to the credit bureaus and lower your CIBIL score. See how your score is calculated.
Other charges to know about
- Cash withdrawals: There is usually a fee, and interest starts from the day you withdraw, with no interest-free period.
- Foreign currency spends: Many cards add a markup, often around 3.5%. Some cards have none. Check before you travel or shop on international sites.
- Annual fee: Some cards charge one, and some waive it if you spend enough. See joining fee vs annual fee.
- GST: Fees and interest charges are subject to GST.
Rules that protect you
RBI’s rules for card issuers require the bank to get your consent before raising your credit limit, and to explain interest and fees clearly. They also stop banks from charging interest on unpaid fees and taxes. If you have a complaint, raise it with the bank first. If it is not resolved within 30 days, you can escalate it to the RBI Ombudsman for free.
Tips for using a card well
- Pay the total amount due every month, not the minimum.
- Set up auto-pay for the full amount, or at least for the minimum as a safety net.
- Keep your usage below about 30% of your limit, which helps your credit score.
- Check each statement for charges you don’t recognise.
- Only spend what you could pay with cash today.
Common questions
Is the minimum amount due a good option?
It keeps your account from going overdue, but it is expensive. You still owe the rest, and interest builds on the unpaid balance. Use it only in an emergency, and clear the balance as soon as you can. Do I pay interest if I pay the full amount on the due date?
No. If you pay the total amount due by the due date, you pay no interest on purchases from that statement. Why did I get charged interest even though I paid most of my bill?
Paying less than the full amount means you lose the interest-free period. Interest can then be charged on the whole amount from the date of purchase, not only the unpaid part. Check your card’s terms to see how your bank calculates it. Does using a credit card build my credit score?
Yes, if you pay on time and keep your usage low. It is one of the easiest ways to build a credit history.
Ready to pick a card? Compare credit cards by fees and rewards. Next in this series: joining fee vs annual fee, and how fee waivers work.
Good first credit cards to look at
If you are getting your first card, these are simple to use and easy to qualify for:
- IDFC FIRST Classic: lifetime free, so there is no annual fee to worry about.
- IDFC FIRST WOW: backed by a fixed deposit, so you can get it without income proof or a credit history.
- SBI SimplyCLICK: a low-fee card with good rewards on online shopping.
- HDFC Millennia: 5% back on popular apps like Amazon, Flipkart and Swiggy.
See all 101 cards with fees and eligibility on our credit cards page, or get a personal pick from the Card Finder.
Disclaimer: This guide is for education and is not financial advice. Fees, rates and benefits differ by card and change often, so check your card’s current terms. Some links on Koshfin are affiliate links; we may earn a commission at no extra cost to you.