Compound-interest and savings-plan calculator
Calculate how initial capital, savings contributions, term and annual return work together.
Calculate compound interest and a savings plan
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Enter your existing initial capital and monthly contribution.
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Enter an assumed annual return and the term.
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Compare your deposits with the calculated interest return in the result.
If you need a bespoke version
You can keep using this free tool as it is. If you need a bespoke version with your own rules, data or workflows for a website, shop or internal process, I can build it for you – for example with custom rules and data sources, approvals and exports, and website or shop integration.
How this tool calculates
Capital earns interest monthly and the savings contribution is added at the end of each month. Taxes, costs and market fluctuations are not included.
Your inputs and results remain on your device. Reloading the page restores the default values.
Terms used in this calculation
- Compound interest
- Returns remain invested and can themselves generate further returns in later periods.
- Return
- The percentage performance of an investment over a period.
- Final capital
- The calculated total value of deposits and returns at the end of the term.
Frequently asked questions
Is the result a guaranteed forecast?
No. The calculator uses a constant return. Real investments fluctuate and may involve costs or taxes.
When is the savings contribution added?
At the end of each month in this calculation.