Compound Interest Calculator
See how savings grow with compound interest: choose compounding (daily to continuous), add deposits at the start or end, and view a yearly table.
Results
Year-by-year growth
| Year | Contributions | Interest | Balance |
|---|---|---|---|
| 1 | 0.00 | 511.62 | 10,511.62 |
| 2 | 0.00 | 537.79 | 11,049.41 |
| 3 | 0.00 | 565.31 | 11,614.72 |
| 4 | 0.00 | 594.23 | 12,208.95 |
| 5 | 0.00 | 624.63 | 12,833.59 |
| 6 | 0.00 | 656.59 | 13,490.18 |
| 7 | 0.00 | 690.18 | 14,180.36 |
| 8 | 0.00 | 725.49 | 14,905.85 |
| 9 | 0.00 | 762.61 | 15,668.47 |
| 10 | 0.00 | 801.63 | 16,470.09 |
- Interest compounds at the chosen frequency; contributions use the equivalent rate per contribution period. Effective rate = (1 + r/n)^n − 1 (eʳ − 1 for continuous).
What is Compound Interest Calculator?
Calculates the future value of an initial amount plus optional regular contributions, compounded annually, semiannually, quarterly, monthly, weekly, daily or continuously. It shows interest earned, total contributions, the effective annual rate (APY) and a year-by-year table.
How to use Compound Interest Calculator
- Enter the Initial amount, Annual interest rate and number of Years.
- Choose the Compounding frequency.
- Optionally add a Regular contribution, its frequency and whether it is made at the start or end of each period.
- Read the future value and the yearly growth table.
Example
10,000 at 5% for 10 years, monthly compounding, 100 per month at the end
Future value 31,998.32; contributions 12,000.00
When to use Compound Interest Calculator
Use it for savings accounts, deposits and long-term illustrations at a fixed rate. Real investments do not earn a constant rate; for a monthly investing plan with inflation adjustment the Investment Calculator is more direct.
How Compound Interest Calculator works
The lump sum grows as P × (1 + r/n)^(n·t), or P × e^(r·t) for continuous compounding. Contributions use the equivalent rate per contribution period, i = (1 + r/n)^(n/m) − 1, and the annuity formula C × ((1 + i)^(m·t) − 1) ÷ i, multiplied by (1 + i) when deposits are made at the start of each period. The effective annual rate is (1 + r/n)^n − 1. Years must be whole numbers so the table lines up with calendar years.
Common Use Cases
- Comparing monthly and daily compounding
- Seeing the effect of adding 100 per month
- Finding the APY of a quoted nominal rate
- Illustrating long-term growth for teaching
FAQs
Does compounding frequency matter much?
Less than people expect: at 5%, annual compounding gives an effective 5.00% and continuous compounding 5.13%.
What is the difference between start and end of period?
Deposits at the start earn one extra period of interest, so the future value is higher by a factor of (1 + i) on the contribution part.
Can the rate be negative?
Yes, values down to −100% are accepted to model losses or negative real rates.