Free Compound Interest Calculator
See how your money could grow. Enter a starting amount, add recurring contributions, pick a compounding frequency, and watch an interactive chart project your balance year by year — with a full breakdown table, CSV export, and a 3-scenario comparison. Free forever, no signup, everything runs in your browser.
Investment details
Projected growth
⚠️ Hypothetical estimates — not financial advice
Results are mathematical projections using a constant rate. They exclude taxes, fees, inflation, withdrawals and changing rates, and they don't predict real market returns. This tool is educational only — not a bank, adviser, or recommendation to invest.
Compound Interest Explained
What is compound interest?
It's interest earned on interest. Each period, your balance grows by the rate — and next period, that bigger balance earns again. A snowball: slow at first, then surprisingly fast. Starting early usually beats investing more later, because compounding rewards time above all. Try our percentage calculator if you want to sanity-check any single percent figure.
How does compounding frequency work?
Frequency decides how often earned interest joins your balance and starts earning its own interest. Daily compounding edges out monthly, which edges out annually — same nominal rate, slightly different result. Over decades the gap becomes real money, which is why the frequency selector above matters for long projections.
Do recurring deposits really matter that much?
Often more than the rate itself. Every contribution is fresh principal that compounds for all remaining years. In the chart above, watch the dark "contributions" line versus the green "balance" line — the gap between them is compounding doing its work on your steady habit. Small, regular amounts beat occasional large ones.
How do I read the yearly breakdown?
Each row shows money in (contributions), growth (interest), and the running totals. Early rows: contributions dominate. Later rows: the interest column swells — that's the crossover point where your money starts working harder than you do. If you're comparing borrowing costs instead, see our loan EMI calculator.
How to Project Your Investment Growth
- Step 1: Enter your initial investment, annual interest rate, and how many years you'll stay invested.
- Step 2: Turn on recurring contributions and choose how often and when they're added.
- Step 3: Study the chart and year-by-year table — then compare up to 3 scenarios side by side.
Why Use Our Compound Interest Calculator?
- Recurring contributions with weekly/monthly/quarterly/annual frequency and timing control
- Interactive growth chart with balance, contributions and interest series
- Year-by-year breakdown table with CSV export
- 3-scenario comparison — free, private, no signup
Frequently Asked Questions
What is compound interest?
Compound interest is interest calculated on both your original money and the interest already earned — so growth accelerates over time. If you earn 5% on $1,000, you get $50 the first year; the next year you earn 5% on $1,050, and so on. Time is the biggest ingredient: the longer money compounds, the faster it grows.
How does compounding frequency affect growth?
More frequent compounding means interest is added — and starts earning its own interest — sooner. Daily compounding beats monthly, which beats annually, for the same nominal rate. The difference is modest at low rates but meaningful over decades.
How do recurring deposits affect growth?
Hugely. Regular contributions add fresh principal that then compounds for the remaining years. In many long-term projections, total contributions end up larger than the interest earned — but without compounding, you'd earn nothing on top. The chart above shows both lines so you can see exactly where growth comes from.
What's the difference between contributions and interest in the results?
Contributions are money you put in (initial deposit plus every recurring payment). Interest is what compounding added on top. Final balance = contributions + interest. The "interest as % of contributions" card tells you how hard your money worked versus how much you fed it.
How do I read the yearly breakdown table?
Each row is one year: opening balance, contributions added that year, interest earned that year, closing balance, plus running totals. The interest column typically starts small and grows each year — that acceleration is compounding in action.
Why might my real returns differ from this projection?
This tool assumes a constant rate, no taxes, no fees, no inflation, and no withdrawals. Real investments fluctuate, charge fees, and get taxed. Treat every number here as a hypothetical estimate for planning — not a prediction or financial advice.