How many kJ is 1 kcal?

1 kcal is approximately 4.184 kJ.

What is kWh used for?

A unit of energy consumption, used for electricity billing.

Is a food "calorie" the same as a physics calorie?

No — nutrition labels use kcal, which is 1,000× the small calorie. 1 kcal = 4.184 kJ.

How much energy is 1 kWh?

3.6 MJ — enough to run a 1,000 W appliance for an hour, or about 860 kcal in heat terms.

⚡ Energy Converter

Convert calories, joules, kWh, BTU and more instantly.

How it works

Type a value in the left field.
Pick the units to convert from and to.
The result updates instantly, with a full reference table below.

Key units & conversion basis

Energy units are converted through joules (J). Nutrition labels actually use kcal when they say "calories", and electricity is billed in kWh — knowing each domain's convention matters.

Unit	Symbol	In J	Common use
Joule	J	1 J	physics base
Kilojoule	kJ	1,000 J	overseas labels
Calorie	cal	4.184 J	small calorie
Kilocalorie	kcal	4,184 J	food energy
Watt-hour	Wh	3,600 J	small loads
Kilowatt-hour	kWh	3,600,000 J	billing
BTU	BTU	1,055.06 J	HVAC capacity

🧮 How the conversion is calculated

Example: 500 kcal to kJ → 500 × 4,184 = 2,092,000 J → ÷ 1,000 = 2,092 kJ. Since 1 kWh = 860 kcal, the same energy is 0.58 kWh.

🎯 When to use this

Convert food nutrition labels between calories and kJ
Check kWh units for electricity bill calculations
Convert joules and BTU for engineering calculations
Convert overseas nutrition labels (kJ) into familiar kcal

📖 Guide: Converting Calories (kcal) to kJ — Reading Overseas Nutrition Labels →

Frequently Asked Questions

How many kJ is 1 kcal?: 1 kcal is approximately 4.184 kJ.
What is kWh used for?: A unit of energy consumption, used for electricity billing.
Is a food "calorie" the same as a physics calorie?: No — nutrition labels use kcal, which is 1,000× the small calorie. 1 kcal = 4.184 kJ.
How much energy is 1 kWh?: 3.6 MJ — enough to run a 1,000 W appliance for an hour, or about 860 kcal in heat terms.