Toolgeist › Math & Unit

ROI Calculator — Free Online Calculator

ROI Calculator solves ROI = (Gain − Cost) / Cost × 100% — measures return as a percentage of what was originally invested. Enter your known values and the calculator solves for the rest instantly. All processing happens client-side in your browser, with nothing sent to a server. Free, unlimited, and no registration needed.

How to use ROI Calculator

1. Enter your known values in the fields.
2. The result updates instantly as you type.
3. Copy or note down the result.

Frequently asked questions

What formula does ROI Calculator use?

ROI = (Gain − Cost) / Cost × 100% — measures return as a percentage of what was originally invested.

Can I use it on my phone?

Yes. The layout adapts to small screens and behaves the same on mobile as on desktop.

Is my input saved anywhere?

No. Values stay in your browser and are gone as soon as you close the tab.

Related Math & Unit tools

• Cap Circuits
• Torus Calc
• 5-Band Res
• Geometry
• Function Plotter
• Amortization

Browse all 738 free tools on Toolgeist →