This interest calculator works out the interest on any amount in rupees, using either simple interest or compound interest. Pick a method, fill in principal, rate per year and period, and read off the interest, the total and a year wise breakdown. With compound interest you also pick how often interest is added.
Most everyday questions fall into one of these two. A loan between friends or a staff advance is usually simple interest. A bank deposit, a recurring deposit or a savings account compounds. This page explains both and links to a dedicated calculator for each common case.
At a glance
- Simple interestP × R × T ÷ 100
- Compound interestP × (1 + r/n)^(n × t) − P
- Example, simple₹1 lakh at 9% for 2 years: ₹18,000
- Example, quarterly compoundSame deposit: ₹19,483
- Monthly interest at 9%₹750 on ₹1 lakh
- Day count365 days in a year
How to use the interest calculator
- Pick Simple interest or Compound interest.
- Type the principal in rupees.
- Type the yearly rate. If someone quotes a monthly rate, such as 1.5% a month, multiply by 12: that is 18% a year.
- Type the time in years. Nine months becomes 0.75 and two and a half years becomes 2.5.
- With compounding, also choose how often interest joins the balance.
The result shows the interest amount, the total, and for simple interest the interest per month and per year. Everything is worked out on your device.
Simple vs compound: the same ₹1 lakh
| ₹1,00,000 at 9% | After 2 years | After 10 years |
|---|---|---|
| Simple interest | ₹18,000 | ₹90,000 |
| Compound, yearly | ₹18,810 | ₹1,36,736 |
| Compound, quarterly | ₹19,483 | ₹1,43,532 |
Over two years the gap is small. Over ten years compounding adds roughly half as much again. When you are the lender or depositor, compounding works for you. When you are the borrower, ask clearly whether unpaid interest gets added to the balance.
Monthly interest calculator: interest per month in rupees
Many people want the per month figure, for example for a private loan at a monthly rate. Simple monthly interest is principal × yearly rate ÷ 1,200.
| Principal | At 12% a year (1% a month) | At 18% a year (1.5% a month) | At 24% a year (2% a month) |
|---|---|---|---|
| ₹50,000 | ₹500 | ₹750 | ₹1,000 |
| ₹1,00,000 | ₹1,000 | ₹1,500 | ₹2,000 |
| ₹5,00,000 | ₹5,000 | ₹7,500 | ₹10,000 |
In private lending, rates are often quoted as rupees per hundred per month: ₹2 per hundred means 2% a month, or 24% a year. That is far higher than any bank loan.
Which interest calculator do you need
| Your question | Calculator |
|---|---|
| Interest that earns interest on a deposit | Compound interest calculator |
| Plain interest on the original amount | Simple interest calculator |
| Interest added every day | Daily compound interest calculator |
| Interest added every month | Monthly compound interest calculator |
| Interest between two dates | Interest calculator date to date |
| The rate hidden in an offer | Interest rate calculator |
| Savings account interest | Savings interest calculator |
| Overdraft or cash credit interest | OD interest calculator |
| Interest on late GST payment | GST interest calculator |
| Bank deposit interest | FD calculator and RD calculator |
| Interest on a loan EMI | EMI calculator |
Interest calculator formula, explained
Simple interest = P × R × T ÷ 100
Compound amount = P × (1 + R ÷ (100 × n))^(n × T)
Here P stands for the amount lent or deposited, R for the percent rate per year, T for years and n for how many times a year interest is credited. For ₹1,00,000 at 9% for 2 years, simple interest is 1,00,000 × 9 × 2 ÷ 100 = ₹18,000. Compounded quarterly: 1,00,000 × (1.0225)^8 = ₹1,19,483, so the interest is ₹19,483.
For a period in days, use T = days ÷ 365. ₹1,00,000 at 9% for 73 days is 1,00,000 × 9 × 73 ÷ 36,500 = ₹1,800.
Bank interest calculator: how banks really count
- Savings accounts use the closing balance of each day and credit interest quarterly.
- Fixed deposits compound quarterly for cumulative FDs and pay out monthly or quarterly otherwise.
- Recurring deposits compound quarterly on each instalment.
- Loans charge interest monthly on the reducing balance, built into the EMI.
- Overdrafts and cash credit charge interest on the daily amount used, debited monthly.
Most banks use a 365 day year. Small differences between this bank interest calculator and your bank statement usually come from rounding, day counting or the exact credit date.
Interest on loans between people
For a private loan, write down the amount, the rate, whether it is simple or compound, and when interest is paid. Courts and lenders often treat interest as simple unless the agreement says otherwise. If interest is due monthly and not paid, decide in writing whether it will be added to the principal.
Very high monthly rates can be unlawful under state money lending laws, and lenders must be licensed in many states. This interest calculator is for working out figures, not legal advice.
Tips for comparing interest offers
- Turn every rate into a yearly figure first.
- Check simple, compound or flat. A flat rate on a loan is much costlier than it looks; see the flat vs reducing page.
- Check how often interest is added. Quarterly beats yearly for a depositor.
- Include fees and taxes. A deposit's after tax yield matters more than its headline rate.
- Use the interest rate calculator when an offer gives only start and end amounts.
Frequently asked questions
How do I calculate interest per month?
For simple interest, multiply the principal by the yearly rate and divide by 1,200. ₹1 lakh at 12% a year is ₹1,000 a month.
What is ₹2 per hundred interest per year?
₹2 per hundred per month means 2% a month, which is 24% a year in simple terms. On ₹1 lakh that is ₹2,000 a month.
Is bank interest simple or compound?
Deposits usually compound, quarterly for FDs and RDs. Loan EMIs charge interest on the reducing balance each month, which is neither flat nor compound on unpaid interest.
How do I find interest for some days?
Multiply principal × rate × days and divide by 36,500. The date to date interest calculator counts the days for you.
Which is better for a depositor, simple or compound interest?
Compound interest, because each period's interest earns interest later. The longer the time, the bigger the gap.
Can this interest calculator work in months?
Yes. Type months as a fraction of a year: 6 months is 0.5, 18 months is 1.5.