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Calculation details
Planning estimate only, not financial, tax, or legal advice. Verify assumptions and current rules before making decisions.
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What does this calculator estimate?
This calculator projects the future value of your savings or investments by compounding your balance monthly at your annual interest rate divided by 12. It applies your regular deposits at either the start or end of each month, depending on your selected timing. The result shows the estimated balance at the end of your time period, so you can use it to compare scenarios or set savings goals.
What is the difference between compounding annually and monthly?
Compounding frequency determines how often earned interest starts earning its own interest. The same nominal rate compounds to a higher future value monthly than annually because each period's interest joins the balance sooner. Over decades the gap is substantial, which is why account terms stating compounding frequency deserve as much attention as the rate itself.
How do I compare a lump sum today against monthly deposits?
Both inputs can produce the same future value, but the paths differ: a lump sum rides market growth for the full period, while deposits average in over time. Run each scenario at the same rate and horizon, then weigh the realistic question of whether the lump sum actually exists today or would be saved anyway.
How this calculator works
Formula
FV = principal x (1 + r/12)^(12n) + monthly x (((1 + r/12)^(12n) - 1) / (r/12)) for end-of-month contributions.
Worked example
$10,000 principal at 6%, compounded monthly for 10 years, grows to about $18,193.97; add $300 monthly contributions ($36,000 over the decade) on top of that base.
Sources
Sources support the method, terminology, or planning context. Editable assumptions remain your responsibility.
Assumptions to verify
- Rate and contributions remain constant.
- Taxes, fees, and market volatility are excluded.
- This is a hypothetical projection, not an investment forecast.
Frequently asked questions
What is a future value calculator and how does it work?
A future value calculator estimates how much your current investment will be worth over time based on compound interest. You simply enter your initial amount, contribution frequency, interest rate, and time period to get an instant projection.
Do I need to create an account or sign up to use this future value calculator?
No, this is a completely no-signup tool. It runs entirely in your browser, so your data is never stored on a server or shared with anyone.
How accurate are the results from this future value calculator?
The results are mathematically accurate based on the inputs you provide, assuming a constant interest rate. However, it does not account for taxes, inflation, or fluctuating market returns, so it is best used for general planning rather than exact financial predictions.
Cite this tool
BoringToolsKit. “Future Value Calculator.” boringtoolskit.com/future-value-calculator/ (reviewed August 2026). Free to reference in articles, syllabi, and answer posts with a link.
Privacy: Inputs and results stay in this browser. Results are planning estimates based on your inputs; verify assumptions and current rules before making decisions.