Energy Converter
Free online energy converter
Popular energy conversions
About energy units
Energy is the capacity to do work. Joule (J) is SI; calorie and BTU are legacy units; Wh/kWh for electricity.
- Food ‘Calorie’: actually kilocalorie (kcal).
- 1 Wh: 3,600 J.
Units in Energy Converter
-
BTU (IT)
(btu)
Common energy unit used in science, engineering, and daily life.
-
Calorie (cal)
(cal)
Calorie (cal) ≈ 4.184 J; used in thermochemistry.
-
Joule (J)
(j)
Joule (J) = 1 N·m = energy of 1 newton over 1 meter.
-
Kilocalorie (kcal)
(kcal)
Kilocalorie (kcal) = ‘food Calorie’; ≈ 4,184 J.
-
Kilowatt-hour (kWh)
(kwh)
1 kWh = 3.6 MJ, the billing unit for electricity.
-
Watt-hour (Wh)
(wh)
Common energy unit used in science, engineering, and daily life.
Quick examples
FAQ
Is energy conversion exact?
Many conversions are exact by definition (e.g., 1 in = 25.4 mm, 1 ft = 0.3048 m).
Can I share a specific result?
Yes. Every converter has a clean, shareable URL like
/convert/meter-to-foot/2.5.