Energy Converter

Every unit has a fixed factor against 1 joule, the SI base unit of energy. To convert between any two units we go through joules: multiply by the source factor to get joules, then divide by the target factor.

J

joule = 1 J (SI base — work done by 1 N force over 1 m)

kJ

kilojoule = 1 000 J

MJ

megajoule = 1 000 000 J

cal

small calorie (cal₁₅) = 4.184 J exactly (thermochemical)

kcal

kilocalorie / food Calorie = 1 000 cal = 4 184 J

BTU

British Thermal Unit ≈ 1 055.06 J (IT) — heats 1 lb water by 1 °F

Wh

watt-hour = 3 600 J

kWh

kilowatt-hour = 3 600 000 J = 3.6 MJ (the electricity-bill unit)

eV

electronvolt = 1.602 176 634 × 10⁻¹⁹ J (SI-defined since 2019)

ft·lbf

foot-pound force ≈ 1.355 818 J

The calorie here is the thermochemical small calorie (4.184 J exactly); the food Calorie with a capital C is a kilocalorie (1 000 cal). Note that BTU and kcal are both "heat" units but with different reference substances and temperature scales — they do not share a common factor.