Compound Interest Calculator
See how savings grow with compound interest and regular monthly deposits. Choose daily, monthly, quarterly or yearly compounding. Year-by-year table. Free.
- Total contributions
- 22,000.00
- Total interest earned
- 9,725.26
- Effective annual rate
- 5%
| Year | Contributions | Interest | Balance |
|---|---|---|---|
| 1 | 11,200.00 | 527.26 | 11,727.26 |
| 2 | 12,400.00 | 1,140.88 | 13,540.88 |
| 3 | 13,600.00 | 1,845.18 | 15,445.18 |
| 4 | 14,800.00 | 2,644.70 | 17,444.70 |
| 5 | 16,000.00 | 3,544.19 | 19,544.19 |
| 6 | 17,200.00 | 4,548.66 | 21,748.66 |
| 7 | 18,400.00 | 5,663.35 | 24,063.35 |
| 8 | 19,600.00 | 6,893.77 | 26,493.77 |
| 9 | 20,800.00 | 8,245.72 | 29,045.72 |
| 10 | 22,000.00 | 9,725.26 | 31,725.26 |
Interest that earns interest
With compound interest, the interest you earn is added to your balance and starts earning interest itself. Over long periods this snowballs: 10,000 at 5% a year grows to about 16,300 after 10 years and 43,200 after 30, without adding another penny. Regular deposits speed it up further. The calculator adds your monthly contribution at the end of each month, compounds at the frequency you choose, and shows the growth year by year, with how much came from your deposits and how much from interest.
How to use it
- 1
Enter your starting amount
What you have saved today. It can be zero.
- 2
Add monthly deposits and the rate
How much you'll add each month and the yearly interest rate.
- 3
Choose the time and compounding
See the balance at the end, and the year-by-year table.
Frequently asked questions
What's the compound interest formula?
A = P × (1 + r/n)^(n × t), where P is the starting amount, r the yearly rate, n the compounding periods a year and t the years. Regular deposits are added on top.
Does compounding frequency matter much?
A little. 5% compounded yearly is 5.00% effective; compounded daily it's 5.13%. Time and the rate matter far more.
What is the rule of 72?
Divide 72 by the yearly rate to estimate how many years it takes to double your money. At 6%, about 12 years.
Is anything sent to a server?
No. Everything is calculated in your browser, and nothing you type is stored or sent anywhere.