Compound Interest Calculator
Explore how time, contributions, and return assumptions combine to grow long-term savings.
Verify this calculatorVerified
See what the result uses—and what it cannot know.
Sumvoro calculates deterministically from the visible inputs. It does not invent lender terms, local rules, market values, medical facts, or professional judgments.
- 1 · InputsCheck every entered value against the latest statement, quote, measurement, or official source.
- 2 · Formula
Future value combines compound growth on the initial balance with the future value of recurring contributions. - 3 · SensitivityUse Insights to run a lower and higher case. If the conclusion changes easily, collect better information or leave more margin.
- 4 · ScopeThis tool is maintained and covered by automated calculation tests. Provider timing, rounding, and omitted facts can still change a real-world result.
- Formula release
- 2026.10-r4
- Release date
- October 10, 2026
- Review status
- Verified
- Source review
- September 12, 2026
Compound Interest calculator
Time, contribution amount, net return, and deposit timing drive the result.
- Use a range of returns.
- Subtract fees and inflation.
- Do not treat returns as guaranteed.
Optional readingLearn how this calculator works
How the compound interest calculator works
Project investment growth with compound returns and regular monthly contributions.
Future value combines compound growth on the initial balance with the future value of recurring contributions.
Read our calculation methodology and limitations.
Treat the projection as a range of assumptions
Compounding is deterministic; investment returns, fees, taxes, and contribution behavior are not.
Test more than one return
Run conservative, middle, and optimistic rates. A plan that succeeds only at the highest assumption has little margin for uncertainty.
Separate deposits from growth
The ending balance combines money contributed with modeled returns. Review both to understand what actually drives the projection.
Use real purchasing power
Inflation can make a larger future balance buy less than expected. Use the inflation option when the goal is stated in today’s dollars.
Example
$10,000 invested for 10 years at 7%, plus $250 each month, grows through both contributions and compounded returns.
What affects the result
- More time allows returns to compound over more periods.
- Regular contributions can matter as much as the starting balance.
- Actual market returns vary and are not guaranteed.
Helpful guides
Frequently asked questions
What does compounding mean?
Compounding means earning returns on both your original money and prior returns.
Is the result guaranteed?
No. It is a mathematical projection based on a constant rate, not a prediction of investment performance.