Compound Interest Calculator
Grow a lump sum plus regular contributions at any compounding frequency.
Enter your values
ⓘ Live results
Results
- Future value
- $170,619.05
- Total contributed
- $70,000.00
- Interest earned
- $100,619.05
- Growth multiple
- 2.44×
Quick answer
Compound interest pays interest on previously earned interest, so a balance grows as A = P(1 + r/n)^(nt) plus the future value of contributions.
A = P(1 + r/n)^(nt)
How to use the Compound Interest Calculator
- 1Enter your starting balance and monthly contribution.
- 2Set an expected annual return and time horizon.
- 3Read the future value and interest earned.
Worked example
Using the values the calculator loads with:
Inputs
- Starting amount10000 $
- Monthly contribution250 $
- Annual return7 %
- Years20 years
- CompoundingMonthly
Results
- Future value$170,619.05
- Total contributed$70,000.00
- Interest earned$100,619.05
- Growth multiple2.44×
Frequently asked questions
What return should I assume?
A diversified stock portfolio has historically returned about 7% a year after inflation, but any single decade can be far higher or lower.
Does compounding frequency matter much?
Less than people expect. At 7%, daily versus yearly compounding differs by roughly a quarter of a percent per year.
About this calculator
- Built and reviewed by James Whitfield · How we build and test calculators
- Report an error
Results are estimates for general information. For medical, legal, structural or financial decisions, confirm with a qualified professional.