Energy Converter
Convert energy between 10 units — joule, kilojoule, calorie, kilocalorie (food calorie), watt-hour, kilowatt-hour, megawatt-hour, BTU, electron-volt, foot-pound.
What powers the Energy Converter
10 units from sub-atomic (eV) to grid-scale (MWh)
Food calorie (kcal = 1,000 small calories)
Electric: Wh, kWh, MWh — what utility meters measure
BTU — US heating/cooling industry
eV for particle physics
Foot-pound for US mechanical engineering
Why the Energy Converter is different
Browser-native
The Energy Converter runs entirely in your browser. Input is processed locally — never uploaded, never logged, never cached anywhere outside your device.
No artificial limits
No daily quotas, no character ceilings, no "upgrade for more" walls. Every feature is the complete feature — the same on the first use as the thousandth.
Production-grade quality
Built to the same engineering bar as paid SaaS tools — accurate algorithms, audited logic, responsive design and accessibility-tested interactions.
Common use contexts
- Nutrition — kcal on food labels to kJ on European labels
- Electricity bills — kWh to joule for physics
- HVAC — BTU to kW for AC sizing (1 ton = 12,000 BTU/h = 3.5 kW)
- Physics homework — joule to eV / calorie
Private and secure
Zero upload
All processing happens in your browser. Input is never transmitted, logged or cached.
Works offline
Once the page loads, the tool runs without an internet connection. No network calls happen during use.
No tracking
No accounts, no cookies for tool state. Only aggregate analytics count visits at the page level.