Energy Converter

Convert energy between the units used in nutrition (kcal, kJ), electricity (Wh, kWh), heating (BTU), physics (J, eV) and engineering (ft·lbf).

Runs in your browser

From

Unit

1 kcal = 4.184 kJ

Factor: 1 kcal = 4.184 kJ

Conversion table: Kilocalorie (food Calorie) (kcal) → Kilojoule (kJ)
kcal	kJ
1 kcal	4.184 kJ
10 kcal	41.84 kJ
50 kcal	209.2 kJ
100 kcal	418.4 kJ
200 kcal	836.8 kJ
300 kcal	1,255.2 kJ
500 kcal	2,092 kJ
1,000 kcal	4,184 kJ
2,000 kcal	8,368 kJ

How to use

Enter an energy value.
Choose the units.
Read the result.

How it works

Everything converts through the joule. The thermochemical calorie is exactly 4.184 J, and a food “Calorie” on labels is a kilocalorie (4,184 J). A kilowatt-hour is 3.6 million joules — the energy used by a 1,000 W device running for one hour.

Examples

Food label: 250 kcal = 1,046 kJ.
Electricity: 1 kWh = 3,412 BTU.

Common uses

Nutrition labels
Electricity and heating bills
Physics homework

Privacy & security

This tool runs entirely in your browser. Your files and text are never uploaded to our servers — processing happens on your device and results are created locally. How each tool handles files

Frequently asked questions

Is a food Calorie the same as a calorie?

No, a food Calorie (capital C) is 1,000 calories, i.e. one kilocalorie.

How do I convert kWh to cost?

Multiply kWh by your electricity price per kWh.

Last updated: September 18, 2026