Compound Interest Calculator
Easify your investments — calculate compound interest and growth.
Calculate compound interest, future investment value, and growth over time. Compare different compounding frequencies.
| Year | Opening Balance | Contributions | Interest Earned | Closing Balance |
|---|
I want a specific amount. How much should I invest? Enter your financial goal and we'll calculate the monthly investment needed.
See the devastating impact of delaying your investments. Every year you wait costs you more than you think.
See why compound interest always wins. Watch the two grow side by side — compound accelerates exponentially while simple grows linearly.
Compare popular Indian investment options side by side. Same monthly amount, same period — see which gives the best returns.
| Investment Type | Rate | Final Value | Interest Earned |
|---|
What will your future wealth actually buy? After accounting for inflation, here's the real purchasing power of your investment.
How to Use
Compound interest is interest calculated on both the principal and the accumulated interest from previous periods, creating exponential growth. Unlike simple interest (which only earns on the original amount), compounding makes your money grow faster over time — Albert Einstein reportedly called it "the eighth wonder of the world."
The Formula
A = P(1 + r/n)nt + PMT × [((1 + r/n)nt - 1) / (r/n)], where P is the principal, r is the annual interest rate, n is the compounding frequency, t is years, and PMT is the regular contribution. The key insight: the exponent (nt) is what creates exponential growth.
Who Needs This Calculator?
Students learning about compounding, young professionals starting to invest, parents planning for children's education, anyone building a retirement corpus. Understanding compound interest is the foundation of all wealth-building strategies.
8 Features That Go Beyond Basics
- Main Calculator: Interactive growth chart with milestone markers, step-up SIP support, inflation adjustment, and tax impact modeling.
- Goal-Based Planner: Reverse-calculate — enter your target amount and find the required monthly SIP or lump sum. Nobody else offers this.
- Cost of Waiting: See exactly how much money you lose by delaying investment by 5, 10, or 15 years. The most motivating feature.
- Compound vs Simple Race: Animated visual comparison showing why compounding always wins, with the exact rupee difference.
- Investment Comparison: Compare FD, PPF, Mutual Funds, Gold, NPS, and Real Estate returns side by side with the same amount and period.
- Real Purchasing Power: After inflation, what does your future wealth actually buy in today's terms? Eye-opening examples included.
- Rule of 72: Quick mental math — how many years to double your money at any interest rate. Visual timeline of sequential doubles.
- Shareable Report: Beautiful downloadable wealth growth card to share with family and friends.
Multi-currency support with Indian lakhs/crores formatting. All calculations are 100% client-side — your financial data never leaves your browser. Cross-link: already have a loan? Check our EMI Calculator.
Frequently Asked Questions
Compound interest is interest earned on both your original investment (principal) and on previously earned interest. For example, if you invest ₹1,00,000 at 10% annually: Year 1 earns ₹10,000 (on ₹1L), but Year 2 earns ₹11,000 (on ₹1.1L). This snowball effect accelerates over time, which is why compounding is so powerful for long-term wealth building.
More frequent compounding means slightly higher returns. For ₹1,00,000 at 12% for 10 years: Annual compounding gives ₹3,10,585; Monthly gives ₹3,30,039; Daily gives ₹3,31,946. The difference is most noticeable at higher rates and longer periods. Most banks compound quarterly or monthly, while savings accounts may compound daily.
The Rule of 72 is a quick mental shortcut: divide 72 by the annual interest rate to estimate doubling time. At 12%, money doubles in ~6 years (72÷12). At 8%, it takes ~9 years. At 6%, ~12 years. It works best for rates between 6-36%. Use our Rule of 72 tab for a visual timeline showing sequential doubles.
Inflation reduces purchasing power over time. If your investment earns 12% but inflation is 6%, your real return is roughly 6%. ₹1 crore in 15 years buys what ~₹42 lakhs buys today (at 6% inflation). Our calculator shows inflation-adjusted values and the "Real Value" tab shows what your future wealth actually buys in today's terms.
Historically, equity mutual funds (~12% avg) outperform FDs (~7%) and PPF (~7.1%) over 10+ year periods. However, FDs and PPF offer guaranteed returns with no market risk. PPF is uniquely tax-free under both Section 80C and Section 10. The best choice depends on your risk tolerance, time horizon, and tax bracket. Use our Compare Investments tab to see exact numbers.
Start a SIP (Systematic Investment Plan) in a mutual fund — you can begin with as little as ₹500/month. Open a PPF account at any bank for guaranteed, tax-free compounding. For FDs, compare rates across banks. The key is to start early — our Cost of Waiting calculator shows that delaying by just 5 years can cost you lakhs. Even small amounts grow dramatically over 15-20 years.
FD interest is taxable at your income tax slab rate (up to 30%). Equity mutual fund LTCG (long-term capital gains above ₹1.25L) is taxed at 12.5%. PPF returns are completely tax-free. NPS gets additional ₹50,000 deduction under 80CCD(1B). Use our calculator's tax rate input (Advanced Options) to see post-tax returns for taxable investments.
If you have a large sum and markets are low, lump sum can give higher returns. But for most people, SIP is better because: (1) it builds discipline, (2) rupee-cost averaging reduces risk, (3) you don't need a large upfront amount. Our Goal Planner shows both options — often a combination of existing savings + monthly SIP is the most practical path to your financial goal.