=Personal FinanceTOOLKIT

Compound Interest Calculator

See how contributions and compounding add up.

Your numbers

Enter your numbers to see the result.

How Compound Interest works

Convert the nominal annual rate and compounding frequency to an effective monthly rate. Starting savings compound monthly; contributions are converted to a monthly equivalent and added at month end. At zero interest, ending balance is starting amount plus all contributions.

A worked example

These sample values illustrate the calculation. Use your own numbers in the calculator for your result.

Example inputs
Starting amount
1000
Contribution amount
100
Contributions per year
12
Annual rate (%)
5
Compounds per year
12
Years
10
Estimated ending balance
$17,175.24
Total contributions
$13,000.00
Hypothetical growth
$4,175.24
Contribution timing
Monthly equivalent at month end

Assumptions and limits

Rates, fees and contribution schedules are the assumptions you enter. This estimate does not include changes you have not entered.

Educational estimate only. This is not personalized financial, investment or tax advice.

When are contributions added?

Contributions are converted to a monthly equivalent and added at month end. The selected compounding frequency determines an equivalent monthly growth rate.