Compound Interest Calculator

See how compounding grows your money over time, or convert a rate between different compounding frequencies.

Ending balance

$31,998.32

Starting amount: $10,000.00
Total contributions: $12,000.00
Total interest earned: $9,998.32
Total deposits (start + contributions): $22,000.00
Interest rate: 5%
Length of time: 10 years
Compounding: Monthly
Effective annual yield (APY): 5.116%

Balance breakdown

Starting amount 31.3%
Contributions 37.5%
Interest 31.2%

Balance by year

Results are estimates and not financial advice.

Year-by-year balance

Year	Total deposits	Total interest	Balance
1	$11,200.00	$539.50	$11,739.50
2	$12,400.00	$1,168.01	$13,568.01
3	$13,600.00	$1,890.06	$15,490.06
4	$14,800.00	$2,710.44	$17,510.44
5	$16,000.00	$3,634.20	$19,634.20
6	$17,200.00	$4,666.60	$21,866.60
7	$18,400.00	$5,813.23	$24,213.23
8	$19,600.00	$7,079.91	$26,679.91
9	$20,800.00	$8,472.79	$29,272.79
10	$22,000.00	$9,998.32	$31,998.32

About the compound interest calculator

Compound interest means you earn interest on your interest. The more often interest is added to the balance, the faster the balance grows, although the difference between monthly, daily and continuous compounding is small.

The Growth tab projects your balance with an initial amount and regular contributions. The Frequency Conversion tab turns a rate quoted under one compounding frequency into the equivalent rate under another, and shows the effective annual yield (APY), which is the fairest way to compare accounts.

Formula

A = P × (1 + r ÷ n)^(n × t) + contributions
APY = (1 + r ÷ n)^n − 1
Equivalent rate with k periods: r₂ = k × ((1 + APY)^(1 ÷ k) − 1)

Example

$10,000 at 5% compounded monthly for 10 years, with $100 added at the end of every month, grows to $31,998.32. A 5% rate compounded monthly has an APY of 5.116%, which equals 5.116% compounded annually.