Finance
Savings goal
Work out the monthly saving needed to hit a target.
Calculators / Finance / Compound interest
Compound interest calculator
See how savings and monthly contributions could grow.
On this page
Future balance55,290.66
Total contributions40,000
Interest earned15,290.66
Calculator controls
How to calculate
See how savings and monthly contributions could grow.
FV = P(1 + r)ⁿ + contribution × ((1 + r)ⁿ − 1) ÷ r
Worked example
Starting balance: 10000; Monthly contribution: 250; Annual interest rate (%): 5; Years: 10.
Future balance: 55,290.66 ; Total contributions: 40,000 ; Interest earned: 15,290.66 .
Assumptions and limits
Monthly compounding; contributions at each month end. Constant hypothetical rate, with no taxes, fees, or inflation. Returns are not guaranteed.
Results are rounded for display; calculations use unrounded values. Read our calculation methodology.
Understanding the result
Future balance includes your contributions and hypothetical interest. The interest-earned amount is the balance minus all money you contributed.
When this tool is useful
Explore how contribution size, time, and an assumed constant rate affect a savings scenario.
Understanding your inputs
| Input | What to enter |
|---|---|
| Starting balance | Enter a number of at least 0 and no more than 10000000000. |
| Monthly contribution | Enter a number of at least 0 and no more than 100000000. |
| Annual interest rate (%) | Enter a number of at least 0 and no more than 100. |
| Years | Enter a number of at least 1 and no more than 100. |
Frequently asked questions
When are monthly contributions added?
At the end of each month, after that month’s growth. Beginning-of-month deposits would receive one extra month of growth.
Is the return guaranteed?
No. The rate is your assumption. Investment returns fluctuate, and taxes, fees, and inflation are excluded.