Method
Each month the balance grows by (annual rate / 100 / 12) and then the monthly contribution is added. Repeating this for years x 12 months gives the future value.
Total contributions = initial amount + monthly contribution x years x 12. Estimated growth = future value - total contributions.
Worked example
| Initial amount | $10,000 |
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| Monthly contribution | $250 |
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| Annual rate | 7% |
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| Years | 20 |
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| Future value | $170,619 |
|---|
| Total contributions | $70,000 |
|---|
| Estimated growth | $100,619 |
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Assumptions and limits
- Assumes a constant annual rate; real investment returns vary and can be negative.
- Fees, taxes and inflation are not deducted, so the result is a nominal projection, not a forecast.
Educational estimate only. It is not financial, tax, legal, or investment advice.
FAQ
How is compound growth calculated here?
The balance is compounded monthly at the annual rate divided by 12, with the contribution added each month. With the defaults the future value is $170,619.
What are total contributions?
The initial amount plus all monthly contributions over the period. With the defaults it is $70,000.
How much of the result is growth?
Growth is the future value minus total contributions. With the defaults it is $100,619.
Does the calculator include fees, taxes or inflation?
No. It is a nominal projection at a constant rate; use the fee or inflation calculators on this network of tools to see their effect separately.
Is my data stored?
No. The calculation runs in your browser and the inputs are not sent to or saved by this site.