Definition
Energy measures the capacity to do work or transfer heat.
E
Unit conversion category
Energy Converter
Convert energy units including joules, calories, kilocalories, watt-hours, kilowatt-hours, and BTU.
Convert energy units including joules, calories, kilocalories, watt-hours, kilowatt-hours, and BTU.
Featured Units
Joule
Kilojoule
Calorie
Kilocalorie
Watt-hour
Kilowatt-hour
BTU
Popular Converters
Educational Guide
Common Uses
Energy conversions support nutrition, electricity billing, HVAC sizing, physics, and battery calculations.
Industries
Utilities, food science, HVAC, automotive, electronics, and research all use energy units.
Tips
Use joules for SI calculations, kilowatt-hours for electric energy, and BTU for many heating and cooling contexts.
Frequently Asked Questions
What is the SI unit of energy?
The joule is the SI derived unit of energy.
What is the difference between calorie and kilocalorie?
One kilocalorie equals 1,000 thermochemical calories and is the food Calorie commonly used on nutrition labels.
How many joules are in a kilowatt-hour?
One kilowatt-hour equals exactly 3,600,000 joules.
Related Categories
Ready to convert energy units?
Explore a popular converter to get a fast, clearly explained result.
Try a popular converter