How to Convert Energy Units
Enter the density value you want to convert in the Value field.
Select the unit you are converting from in the From dropdown.
Select the unit you want to convert to in the To dropdown.
Click Convert to see the result.
Key Features
35 Energy Units
Covers SI units (joule, kilojoule, megajoule), electrical units (watt-hour, kilowatt-hour, megawatt-hour), thermal units (calorie, kilocalorie, BTU, therm), atomic units (electron volt, erg), and mechanical units (foot-pound, horsepower hour, and more).
High-Precision Results
Conversions use exact factor values, with intelligent formatting that avoids unnecessary scientific notation for everyday values while handling extreme scales correctly.
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Frequently Asked Questions
What is the base unit used for conversions?
All conversions go through the joule (J), the SI base unit of energy. Each unit's factor represents how many joules it equals.
What is the difference between calorie (IT), calorie (th), and kilocalorie?
The International Table calorie (cal IT) equals exactly 4.1868 J. The thermochemical calorie (cal th) is 4.184 J. The kilocalorie (kcal), also called a food calorie or Calorie (capital C), equals 4186.8 J — 1000 times the IT calorie.
What is the difference between BTU (IT) and BTU (th)?
The International Table BTU equals 1055.05585262 J. The thermochemical BTU is 1054.35026444 J. They differ by less than 0.07%, but the IT value is the internationally recognized standard.
How do I convert kilowatt-hours to joules?
Select kilowatt-hour as the From unit and joule as the To unit. One kilowatt-hour equals 3,600,000 joules (3.6 MJ).
What is a quad?
A quad is a unit of energy equal to one quadrillion (10^15) BTU, or approximately 1.055 × 10^18 joules. It is used to describe large-scale energy production and consumption at the national or global level.