Calories to Watt-hours Converter

How to convert Calories to Watt-hours

To convert Calories to Watt-hours, multiply the value in Calories by 0.0011622222. For example, 5 cal = 0.0058111111 Wh.

Converting Calories (cal) to Watt-hours (Wh) is a frequent need, and the exact relationship is 1 cal = 0.0011622222 Wh. Whether you're working on a project, checking a specification, or just curious, the calculator above gives you the answer instantly for any value you enter.

Energy conversions appear in nutrition, fitness, physics, utility bills, and engineering. The same quantity of energy can be expressed in joules, calories, kilowatt-hours, or BTU depending on the context.

Understanding Calories and Watt-hours

The joule is the SI unit, but everyday contexts use others: food labels use kilocalories (often just called 'calories'), electricity bills use kilowatt-hours, and heating and cooling systems use BTU (British Thermal Units). One food calorie is actually a kilocalorie — 1,000 of the small physics calories — which is a frequent source of confusion.

How accurate is this conversion?

Energy conversions use standard definitions: 1 calorie = 4.184 joules, 1 kilowatt-hour = 3,600,000 joules, 1 BTU = 1,055.06 joules. These are internationally agreed values, making the conversions exact.

All conversion factors on ClearUnits are based on internationally recognised standards (the International System of Units, SI, and official definitions). Factors are reviewed for accuracy and the calculator uses full-precision values, rounding only the displayed result.

Quick reference: common Calories to Watt-hours values

The most frequently searched conversions are 1 Calories = 0.0011622222 Watt-hours, 5 Calories = 0.0058111111 Watt-hours, 10 Calories = 0.011622222 Watt-hours, and 100 Calories = 0.11622222 Watt-hours. The full table further down covers every common value, and the calculator handles any number you need in between.