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About Energy Converter Online
This tool converts between energy units including joules, kilojoules, calories, kilocalories (food calories), watt-hours, kilowatt-hours, electronvolts, BTU, and foot-pounds.
Energy conversions are needed in physics and chemistry (joules, electronvolts), nutrition (kcal), electricity billing (kWh), heating engineering (BTU), and mechanical calculations (foot-pounds). Having all units in one converter eliminates the need to chain multiple conversions.
All conversions use scientifically precise conversion factors defined by international standards.
How to use this tool
How to convert energy units
Enter the energy value
Type the number in the Value field. Scientific notation such as 1.5e6 is accepted.
Pick the source unit
From offers J (joules), kJ (kilojoules), kcal (kilocalories), and kWh (kilowatt-hours). 1 kcal = 4184 J exactly.
Pick the target unit
To lists the same units. Food labels often mix kcal and kJ (1 kcal = 4.184 kJ); electricity bills use kWh (1 kWh = 3,600,000 J).
Press Run
Result is computed via joules as the bridge with 12 significant digits. Round per your context — nutrition labels, electricity bills, physics homework.