Summary
A compound interest calculator shows what your money grows to when earned interest is added to the balance and starts earning interest too. To use this one free and privately, type the Initial Investment, the annual Interest Rate and the Time Period, pick how often interest compounds (yearly, half-yearly, quarterly, monthly or daily) and set Monthly Deposits, which starts switched on at ₹5,000: type your own amount, or switch it off for a lump sum only. The result appears instantly and nothing you type is uploaded.
The lump sum follows A = P × (1 + r/n)^(n×t). Monthly deposits grow at the equivalent monthly rate, so all your money compounds at the same effective annual rate, (1 + r/n)^n − 1. Interest that is not reinvested is a different calculation: use the simple interest calculator, or the interest calculator to see both methods. As a quick check, money doubles in about 72 ÷ rate years: roughly 6 years at 12%.
Table of Use: Example Inputs and Results
Every row was produced with this calculator’s formulas and is shown as the tool shows it, rounded to whole currency units. The rates are illustrations, not quotes from any bank or fund.
| Situation | What you enter | What it shows |
|---|---|---|
| Lump sum, yearly | ₹1,00,000, 12%, 10 years, Yearly, deposits off | Final Amount ₹3,10,585; effective annual rate 12.00% |
| Same lump sum, monthly | Compounding Frequency set to Monthly | ₹3,30,039; effective annual rate 12.68% |
| Lump sum plus monthly deposit | ₹1,00,000, 12%, 10 years, Monthly, ₹5,000 at End of each month | ₹14,80,232; Total Invested ₹7,00,000; Interest Earned ₹7,80,232 |
| SIP-style deposits only | ₹0 initial, ₹10,000 at Start of each month (SIP style), 12%, 15 years, Monthly | ₹50,45,760; Total Invested ₹18,00,000; Interest Earned ₹32,45,760 |
| Fixed-deposit style | ₹5,00,000, 7%, 5 years, Quarterly, deposits off | ₹7,07,389; effective annual rate 7.19% |
| US dollar savings | Currency USD, $10,000, 5%, 10 years, Monthly, deposits off | $16,470; Interest Earned $6,470; effective annual rate 5.12% |
To measure the return on something you already own, use the investment calculator, which also finds the CAGR of a past investment.
Features
- Five compounding frequencies: yearly, half-yearly, quarterly, monthly (12×) and daily (365×).
- Optional monthly deposits at the end of each month or the start of each month (SIP style).
- Clear results: Final Amount, Total Invested, Interest Earned, Growth on money invested, Effective annual rate and an Amount Breakdown chart.
- Year-wise Growth table with Opening, Deposits, Interest and Closing for every year.
- CSV and PDF export, created on your device and named like compound-interest-INR-12pct-10y.
- Nine display currencies (INR, USD, EUR, GBP, AUD, CAD, SGD, AED, JPY). The choice changes the symbol and digit grouping only, with no conversion; the currency converter handles that.
- Input checks: rates from 0% to 100%, whole years from 1 to 100, and amounts up to 10 trillion.
Know the limits: the rate stays constant, there are no withdrawals or yearly deposit increases, and tax, fund charges and inflation are not deducted. Estimate tax with the income tax calculator, and turn a result into a percentage change with the percentage calculator.
How to Use the Compound Interest Calculator
- Choose the Currency for display. The default is INR.
- Type the Initial Investment. Enter 0 to model monthly deposits only.
- Enter the Interest Rate (% per annum), for example 12.
- Set the Time Period (Years, 1–100).
- Pick the Compounding Frequency your bank or fund states.
- Monthly Deposits is on by default with ₹5,000: type your amount and choose the Deposit timing, or switch it off to model a lump sum only.
- Read Final Amount and Interest Earned, scroll the Year-wise Growth table, and press CSV or PDF to save a copy.
There is no Calculate button: figures update as you type. Everything runs in your browser and nothing is uploaded, as the Network tab in DevTools will show.
Who Can Use It
Savers can compare deposits by entering each rate and compounding frequency. Regular investors can set a monthly plan against a lump sum, then test it against a target in the savings calculator or the retirement calculator. Students can follow the yearly table to watch the formula work.
Borrowers need a tool built for debt, because this one models growth, not repayment. Try the EMI calculator, the loan calculator or the mortgage calculator.
FAQs
What is the compound interest formula?
The compound interest formula is A = P × (1 + r/n)^(n×t), where P is the starting amount, r the annual rate as a decimal, n the compounding periods per year and t the years. Interest earned is A − P. For ₹1,00,000 at 12% compounded monthly for 10 years, A = 1,00,000 × 1.01^120 = ₹3,30,039, so the interest is ₹2,30,039.
How do I calculate compound interest with monthly deposits?
Enter the initial investment, rate, years and compounding frequency, leave Monthly Deposits switched on (it is on by default) and type the amount. The calculator converts the quoted rate to a monthly growth factor, g = (1 + r/n)^(n/12), and applies it 12 times a year: balance × g + deposit for end-of-month deposits, (balance + deposit) × g for start-of-month deposits.
What is the difference between simple and compound interest?
Simple interest is paid only on the original amount, while compound interest is paid on the amount plus the interest already added. At 12% for 10 years, ₹1,00,000 earns ₹1,20,000 as simple interest but ₹2,10,585 when compounded yearly, because each year’s interest starts earning interest of its own.
Is daily compounding much better than monthly compounding?
No. ₹1,00,000 at 12% for 10 years reaches ₹3,10,585 with yearly compounding, ₹3,30,039 with monthly and ₹3,31,946 with daily. Yearly to monthly adds ₹19,454; monthly to daily adds only ₹1,907. The effective annual rate rises from 12.00% to 12.68% and 12.75%, so compare products by that rate.
Why is my bank’s maturity amount different from this calculator?
Banks apply their own rules: interest may be credited on fixed dates, rates can change and tax may be deducted at source. This calculator assumes one constant rate, applies the compounding frequency you pick and ignores tax, fees and inflation. Enter the rate and frequency printed on your deposit certificate and expect small differences.
Is it safe to enter my savings amounts into an online calculator?
On this page, yes. The calculation runs in your browser and the amounts you type are never uploaded. To check, open DevTools, choose the Network tab and change a value: no request carries your figures. The CSV and PDF files are built on your device; the PDF code may download once, without your data, when you first press PDF.