Compound Interest Calculator
Calculate compound interest with customizable compounding frequency. Compare against simple interest and see year-by-year growth — all computed in your browser.
Currency
Investment Details
$
$1,000$100,000,000
% p.a.
0.1% p.a.50% p.a.
yr
1 yr50 yr
Final Amount (Compound)
$164.5K
$164,531
Total Interest (CI)
$64.5K
64.5% of principal
Simple Interest Total
$150.0K
SI: $50.0K
Compounding Advantage
+$14.5K
Extra earned vs simple interest over 5 years
Principal60.8%Interest39.2%
Year-by-Year Comparison
| Year | Compound Total | CI Interest | Simple Total | SI Interest |
|---|---|---|---|---|
| 1 | $110.5K | +$10.5K | $110.0K | +$10.0K |
| 2 | $122.0K | +$22.0K | $120.0K | +$20.0K |
| 3 | $134.8K | +$34.8K | $130.0K | +$30.0K |
| 4 | $148.9K | +$48.9K | $140.0K | +$40.0K |
| 5 | $164.5K | +$64.5K | $150.0K | +$50.0K |
Frequently Asked Questions
- What is compound interest?
- Compound interest is interest calculated on both the initial principal and the accumulated interest from previous periods. This means your money grows faster than with simple interest, where interest is only calculated on the principal.
- What is the compound interest formula?
- A = P(1 + r/n)^(nt), where A is the final amount, P is the principal, r is the annual interest rate (as a decimal), n is the number of times interest compounds per year, and t is time in years.
- What compounding frequency gives the best returns?
- More frequent compounding gives slightly higher returns. Daily compounding yields more than monthly, which yields more than annually. The difference becomes more significant over longer periods and at higher interest rates.
- What is the difference between compound and simple interest?
- Simple interest is calculated only on the principal (SI = P × r × t). Compound interest is calculated on the principal plus accumulated interest, resulting in exponential growth. Over long periods, compound interest can generate significantly more wealth.
- Is this compound interest calculator free?
- Yes, 100% free. No account required. All calculations happen instantly in your browser — nothing is sent to any server.
- Does it work on mobile?
- Yes, the calculator works on all modern browsers including mobile Safari and Chrome on iOS and Android.