About the ROI Calculator
ROI Calculator does the math for you. Enter your values in the format shown and the result appears immediately — no spreadsheets, no formulas to remember, and nothing is uploaded to a server.
How ROI Calculator works
ROI = net profit ÷ investment cost × 100.
Worked example: Profit 500 on 2000 cost = 25% ROI
How to use
- Enter your values as shown in the input box.
- The result is calculated instantly.
- Click Copy to use it.
Common uses
- Quick everyday math.
- Double-checking figures fast.
- Schoolwork and homework.
- Finance, health and planning.
Frequently asked questions
Is my data uploaded?
No — the calculation runs entirely in your browser, so your data stays private.
Is it free?
Yes — completely free with no sign-up.