Compound Interest Calculator

Calculate ending balance, contributed principal, and earned interest from a starting amount, monthly deposits, nominal rate, and frequency.

Compound interest terms

Convert a nominal annual rate and compounding frequency into consistent monthly growth.

Initial principal

Results use the same monetary unit as the amounts you enter.

Monthly contribution

Nominal annual rate (%)

Duration (years)

Compounding frequency

Compound growth estimate

Yearly compound interest summary
Year	Contributed	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

Converts annual, quarterly, monthly, or daily compounding into a consistent effective monthly rate.
Applies monthly contributions at the end of each month before reporting the ending balance.
Separates contributed principal from mathematically earned interest.
Summarizes cumulative contributions, interest, and balance for durations from 1 through 100 years.

Enter the initial principal and end-of-month contribution.
Choose the nominal annual rate, a 1–100 year duration, and compounding frequency.
Review the ending balance, yearly detail, and stated assumptions.

Compare savings scenarios
Change rate, term, and compounding frequency to compare ending balance and total interest.
Inspect recurring contribution impact
Add a month-end contribution and separate contributed principal from interest earned.

Inputs and compound-interest calculations remain in your browser and are not transmitted or stored.

Daily compounding uses 365 periods and contributions occur at month-end. Taxes, fees, market volatility, and guaranteed returns are excluded.

When are recurring contributions applied?: Monthly contributions are added at the end of each month, while the nominal annual rate follows the selected annual, quarterly, monthly, or daily compounding frequency.
Are taxes or fees included?: No. This is a mathematical projection using only the principal, nominal annual rate, term, compounding frequency, and monthly contribution you enter.