Compound Interest Calculator
Calculate compound interest with growth chart and contributions
Compound Interest Calculator is a free, browser-based tool that lets you calculate compound interest with growth chart and contributions — with zero signup, zero installation. Your data never leaves your browser. Part of 116+ free developer and business tools at wowhow.cloud, built and maintained by a team with 14+ years of hands-on development experience.
Total
$106.6K
Initial Investment
$10,000
Total Contributions
$60,000
Interest Earned
$36,639
Final Amount
$106,639
Effective Growth
52.3%
Simple Interest
$7,000
SI Total
$77,000
CI Advantage
$29,639
Year-by-Year Growth
Compound Interest vs Simple Interest
Simple Interest
$7,000
Total: $77,000
Compound Interest
$36,639
Total: $106,639
Extra with CI
$29,639
423.4% more
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About Compound Interest Calculator
Compound interest is the foundational principle behind every investment — the idea that interest earns interest. Albert Einstein reportedly called it the eighth wonder of the world, and for good reason: at 12% compounding annually, Rs 1 lakh becomes Rs 3.1 lakh in 10 years and Rs 9.6 lakh in 20. This calculator lets you explore the full power of compounding across frequencies (daily, monthly, quarterly, annual) with optional monthly contributions, and compares the result against simple interest.
How It Works
The compound interest formula A = P(1 + r/n)^(nt) is the core engine. P is the principal (initial amount), r is the annual interest rate as a decimal, n is the number of compounding periods per year (365 for daily, 12 for monthly, 4 for quarterly, 1 for annual), and t is the time in years.
When you add monthly contributions, each contribution is treated as a separate deposit that compounds for its remaining tenure. The combined result is the sum of the principal's compounded value and the future value of the annuity formed by the monthly contributions. The year-by-year table shows both the cumulative contributions and the total portfolio value, making it easy to see how much of the growth comes from contributions versus compounding.
The simple interest comparison uses SI = P × r × t, showing the dollar (or rupee) difference between simple and compound growth — which becomes dramatic over 20+ year horizons.
Who Is This For
A student learning about investing comparing how Rs 10,000 grows at 8% under daily, monthly, quarterly, and annual compounding over 30 years.
A savings account holder checking the impact of daily compounding versus quarterly compounding when choosing between two bank accounts.
A finance teacher demonstrating why starting to invest Rs 5,000/month at 25 versus 35 results in a dramatically different retirement corpus.
An investor modelling a Rs 50 lakh inheritance plus Rs 10,000/month additional savings at 10% for 15 years.
Scope note: Uses the standard compound interest formula — a mathematical model assuming a constant interest rate throughout the period. Real investments (equity, mutual funds) have variable annual returns. For bank FDs and small savings schemes, verify the actual compounding frequency with your financial institution. The monthly contribution model assumes contributions are made at the start of each month.
How to Use
Enter the principal (initial investment) amount
Set the annual interest rate
Choose time period and compounding frequency
Optionally add monthly contributions for recurring investment growth
Frequently Asked Questions
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