Compound Interest Calculator
📦 Compound Interest Calculator Source Code $4.99
Get the complete, ready‑to‑deploy HTML file with all styling and logic. This is the exact code powering the demo above — no dependencies, works offline, and 100% client‑side. Supports multiple compounding frequencies (annual, semiannual, quarterly, monthly, daily, continuous), monthly contributions with start/end timing, and a full year‑by‑year breakdown. Includes preset rates for PPF (7.1%), NSC (7.7%), top FD (8%), and equity (10-12%) based on 2026 Indian market rates[reference:3][reference:4][reference:5]. Perfect for financial planning, retirement projections, and wealth management. One‑time purchase, lifetime access.
What Is Compound Interest?
Compound interest is the interest calculated on the initial principal and also on the accumulated interest from previous periods. It's the force behind long‑term wealth creation — Albert Einstein famously called it the "eighth wonder of the world." This tool projects investment growth using the formula: A = P(1 + r/n)^(nt), where A is the future value, P is the principal, r is the annual interest rate, n is the number of compounding periods per year, and t is the time in years. It also supports regular monthly contributions and provides a year‑by‑year breakdown to help you visualise how your money grows over time.
How to Use
- Enter your initial investment — the principal amount you're starting with.
- Add optional monthly contributions — regular deposits you'll make each month.
- Set the annual interest rate — use the preset buttons for PPF (7.1%), NSC (7.7%), top FD (8%), or equity (10-12%) based on 2026 Indian market rates.
- Choose the compounding frequency — annually, semiannually, quarterly, monthly, daily, or continuously.
- Specify the time period — enter years and months.
- Click "Calculate" — view your future value, total contributions, interest earned, CAGR, and a detailed year‑by‑year breakdown.
Frequently Asked Questions
What is CAGR and how is it calculated?
CAGR (Compound Annual Growth Rate) is the average annual growth rate of your investment over time, assuming profits are reinvested. It's calculated as (Ending Value / Starting Value)^(1/Years) − 1. This metric helps you compare different investment returns on a consistent basis.
Does this tool work offline?
Yes. Once the page loads, all calculations happen locally in your browser. No network requests are made.
What is continuous compounding?
Continuous compounding assumes interest is compounded an infinite number of times per year. The formula used is A = P × e^(rt), where e is Euler's number (≈2.71828). It represents the theoretical maximum return for a given rate and time period.
Disclaimer: This tool performs all operations locally in your browser. No data is stored, transmitted, or logged. Results are for informational and educational purposes only and do not constitute financial advice. Always consult a qualified financial advisor for investment decisions.