Calculator
Compound Interest Calculator
The lump sum you invest today.
How often interest is added to the balance.
Growth over time
- Principal
- Interest
View yearly breakdown
| Year | Principal | Interest | Total |
|---|---|---|---|
| Y1 | ₹1,00,000 | ₹8,243 | ₹1,08,243 |
| Y2 | ₹1,00,000 | ₹17,166 | ₹1,17,166 |
| Y3 | ₹1,00,000 | ₹26,824 | ₹1,26,824 |
| Y4 | ₹1,00,000 | ₹37,279 | ₹1,37,279 |
| Y5 | ₹1,00,000 | ₹48,595 | ₹1,48,595 |
| Y6 | ₹1,00,000 | ₹60,844 | ₹1,60,844 |
| Y7 | ₹1,00,000 | ₹74,102 | ₹1,74,102 |
| Y8 | ₹1,00,000 | ₹88,454 | ₹1,88,454 |
| Y9 | ₹1,00,000 | ₹1,03,989 | ₹2,03,989 |
| Y10 | ₹1,00,000 | ₹1,20,804 | ₹2,20,804 |
Assumes a constant rate and no withdrawals or additional deposits. Interest on FDs and most debt instruments is taxable as per your slab; this figure is pre-tax.
Compound interest is interest earned on both your original money and the interest already added — the engine behind long-term wealth. This calculator shows how a one-time investment grows over time at a chosen rate and compounding frequency, separating your principal from the interest earned. Use it to understand FDs, bonds, or any lump-sum investment, and to see why starting early matters far more than the exact rate you earn. Everything is in ₹ at Indian rates — FDs, RDs, bonds, and PPF — so the numbers match how Indian banks and small-savings schemes quote compounding.
What your result means
- Notice how the interest portion grows faster than the principal over time — that acceleration is the whole point of compounding.
- Time matters more than the amount: starting five years earlier usually beats investing a larger sum later.
- A small change in the rate becomes a large change in the maturity over long periods — which is why fees and a percent or two of extra return matter so much.
How to use this calculator
- Enter the lump sum you plan to invest.
- Enter the annual interest rate offered.
- Set the number of years you will stay invested.
- Pick how often interest compounds — quarterly for most Indian FDs.
- Compare the interest earned against the principal to feel the effect of time.
The formula
A = P × (1 + r/k)^(k × t), where A = maturity value, P = principal, r = annual rate (as a decimal), k = compounding periods per year, and t = years. Interest earned = A − P.
Worked example
₹1,00,000 invested at 8% per year, compounded quarterly (k = 4) for 10 years: A = 1,00,000 × (1 + 0.08/4)^(40) ≈ ₹2,20,800. So ₹1,20,800 is interest. The same amount at simple interest would earn only ₹80,000 — the extra ₹40,800 is compounding at work. Over 25 years the gap widens to lakhs.
When to use it
- Estimating the maturity value of a fixed deposit or bond.
- Understanding how compounding frequency changes the final amount.
- Demonstrating to yourself why early investing beats a higher rate started later.
- Comparing a lump-sum investment against the same money left idle.
Frequently Asked Questions
References & sources
How this calculator was checked: The compound-interest formula (A = P x (1 + r/k)^(k x t), the standard compounding formula) was checked against its derivation and re-run against the worked example on 2026-07-27 -- the Rs2,20,800 maturity and Rs1,20,800 interest figures match the formula's actual output exactly, so no correction was needed. Not reviewed by a registered investment adviser.