Energy Unit Converter (J, cal, kWh, BTU, eV)
Energy Unit Converter (J, cal, kWh, BTU, eV)
Energy shows up in many different units depending on the field: physics uses joules, nutrition uses calories, electricity bills use kilowatt-hours, HVAC uses BTU, and particle physics uses electronvolts. This calculator converts between all five, using joules as the common base unit.
Routing every conversion through joules as a common intermediate unit is what makes converting directly between any two of the five units possible without needing a separate formula for every possible pair — 1 calorie equals 4.184 joules, 1 kilowatt-hour equals exactly 3.6 million joules (which is why electricity bills, priced per kWh, represent such an enormous number of joules per unit), and 1 electronvolt is an almost unimaginably tiny 1.602×10⁻¹⁹ joules, reflecting the vastly different scales these units were each designed to describe conveniently.
- All conversions pass through joules as the base unit - e.g. 1 cal = 4.184 J, 1 kWh = 3,600,000 J, 1 BTU = 1055.06 J, 1 eV = 1.602×10⁻¹⁹ J.
- 1000 J ≈ 239.006 cal - useful when comparing a food's calorie content to physics-based energy figures.
- 1 kWh = 3.6 million joules - this is why electricity bills use kWh instead of joules; the numbers stay manageable.
How do I convert joules to calories?
Divide by 4.184 - e.g. 1000 J ÷ 4.184 ≈ 239.006 cal.
How many joules are in a kilowatt-hour?
1 kWh = 1000 W × 3600 s = 3,600,000 J.
Energy Unit Converter (J, cal, kWh, BTU, eV)
Energy shows up in many different units depending on the field: physics uses joules, nutrition uses calories, electricity bills use kilowatt-hours, HVAC uses BTU, and particle physics uses electronvolts. This calculator converts between all five, using joules as the common base unit.
Routing every conversion through joules as a common intermediate unit is what makes converting directly between any two of the five units possible without needing a separate formula for every possible pair — 1 calorie equals 4.184 joules, 1 kilowatt-hour equals exactly 3.6 million joules (which is why electricity bills, priced per kWh, represent such an enormous number of joules per unit), and 1 electronvolt is an almost unimaginably tiny 1.602×10⁻¹⁹ joules, reflecting the vastly different scales these units were each designed to describe conveniently.
- All conversions pass through joules as the base unit - e.g. 1 cal = 4.184 J, 1 kWh = 3,600,000 J, 1 BTU = 1055.06 J, 1 eV = 1.602×10⁻¹⁹ J.
- 1000 J ≈ 239.006 cal - useful when comparing a food's calorie content to physics-based energy figures.
- 1 kWh = 3.6 million joules - this is why electricity bills use kWh instead of joules; the numbers stay manageable.
How do I convert joules to calories?
Divide by 4.184 - e.g. 1000 J ÷ 4.184 ≈ 239.006 cal.
How many joules are in a kilowatt-hour?
1 kWh = 1000 W × 3600 s = 3,600,000 J.