What is a joule?

Definition

J

The joule (J) is the SI unit of energy, equal to the work done by a force of one newton over one meter.

Unit system

SI / Metric

Convert joules

Joules → Kilojoules Joules → Megajoules Joules → Calories Joules → Kilocalories Joules → Watt-hours Joules → Kilowatt-hours Joules → Megawatt-hours Joules → British Thermal Units

All energy units

Unit	Symbol	System
joules	J	SI / Metric
kilojoules	kJ	SI / Metric
megajoules	MJ	SI / Metric
calories	cal	Heat & Food
kilocalories	kcal	Heat & Food
watt-hours	Wh	Electrical
kilowatt-hours	kWh	Electrical
megawatt-hours	MWh	Electrical
BTU	BTU	Imperial
electronvolts	eV	Scientific
foot-pounds	ft·lb	Imperial
ergs	erg	Scientific