Compound interest calculator
Watch interest earn interest, year by year, with or without regular deposits.
Final balance
Final balance: US$16,470.09
- Total deposited
- US$10,000.00
- Interest earned
- US$6,470.09
- Effective annual rate (APY/AER)
- ≈ 5.1162%
Year by year
| Year | Total deposited | Interest earned |
|---|---|---|
| 1 | US$10,000.00 | US$511.62 |
| 2 | US$10,000.00 | US$1,049.41 |
| 3 | US$10,000.00 | US$1,614.72 |
| 4 | US$10,000.00 | US$2,208.95 |
| 5 | US$10,000.00 | US$2,833.59 |
| 6 | US$10,000.00 | US$3,490.18 |
| 7 | US$10,000.00 | US$4,180.36 |
| 8 | US$10,000.00 | US$4,905.85 |
| 9 | US$10,000.00 | US$5,668.47 |
| 10 | US$10,000.00 | US$6,470.09 |
How it works
With compound interest, each period’s interest is added to the balance and earns interest itself. The more often interest compounds, the higher the effective annual rate, shown as APY or AER.
Regular deposits are grown at the rate equivalent to the compounding for their own interval, so monthly deposits with daily compounding are handled exactly. Deposits at the start of a period earn one extra period of interest.
The chart shows, for each year, how much of the balance is your money and how much is interest. Taxes, fees and changes in the rate are not included.
Formula
Balance = P × (1 + r ÷ m)^(m × t) + D × ((1 + i)^N − 1) ÷ i i = (1 + r ÷ m)^(m ÷ p) − 1 (rate per deposit interval) N = p × t deposits; × (1 + i) for deposits at the start Continuous: P × e^(r × t) APY = (1 + r ÷ m)^m − 1
Worked example
10,000 at 5% compounded monthly for 10 years grows to 16,470.09, of which 6,470.09 is interest; the effective annual rate is 5.1162%. Adding 100 at the end of every month brings the balance to 31,998.32.
Questions people ask
How much difference does daily compounding make?
Less than people think. At 5%, yearly compounding gives 5% a year, monthly 5.116% and daily 5.127%.
What is the difference between APR and APY?
APR is the nominal yearly rate before compounding; APY (called AER in the UK) is the rate you actually earn once compounding is included.
Does this include inflation or tax?
No. The result is in today’s nominal money before tax. Use the inflation calculator to see its future purchasing power.