J (joule) and Ws (watt second) are the valid SI units for energy. Nevertheless, in the energy sector a lot of other units are used. This overview describes the most important units of energy and their conversion factors. A specialized calculator assists at these calculations.

Units of Energy Calculator →

	kJ	kcal	kWh
1 kJ	1	0.2388	0.000278
1 kcal	4.1868	1	0.001163
1 kWh	3 600	860	1
1 kg SKE	29 308	7 000	8,14
1 kg oe	41 868	10 000	11,63
1 m³ natural gas	31 736	7 580	8.816

	kg SKE	kg RÖE	m³ natural gas
1 kJ	0.000034	0.000024	0.000032
1 kcal	0.000143	0.0001	0.00013
1 kWh	0.123	0.086	0.113
1 kg SKE	1	0.7	0.923
1 kg oe	1.428	1	1.319
1 m³ natural gas	1.083	0.758	1

Unit	Name
J	Joule
cal	Calorie
Wh	Watt hour
(kg) SKE	(kilogram) Coal equivalent
(kg) RÖE	(kilogram) Oil equivalent
oe oder OE	Oil equivalent
m³ Erdgas	cubic meter natural gas
BTU	British thermal unit
kpm	Kilogram force meter (Kilopondmeter)
erg	Erg
eV	Electron volt

Unit	Conversion in kJ or kWh
J	1 000 J = 1 000 Ws = 1 kJ
cal	1 000 cal = 1 kcal = 4,186 kJ
Wh	1 Wh = 3,6 kJ
(kg) SKE	1 kg SKE = 29 308 kJ
(kg) RÖE	1 kg RÖE = 41 868 kJ
oe oder OE	1 (kg) oe = 41 868 kJ
m³ natural gas	1 m³ Erdgas = 31 736 kJ
BTU	1 BTU = 0.000293071 kWh = 1.05506 kJ
kpm	1 kpm = 2.72·10-6 kWh = 0.00980665 kJ
erg	1 erg = 2.78·10-14 kWh = 1·10-10 kJ
eV	1 eV = 1.60217733·10-19 J = 1.60217733·10-22 kJ