How many watt-hours are in one calorie?

One thermochemical calorie (cal) equals approximately 0.001162 watt-hours (Wh). That is 4.184 joules divided by 3,600 joules per watt-hour.

How many watt-hours are in one kilocalorie (kcal)?

One kilocalorie (kcal) equals approximately 1.162 watt-hours (Wh), or about 0.001162 kilowatt-hours (kWh).

What is the difference between cal and kcal?

A small calorie (cal) raises 1 gram of water by 1 °C. A kilocalorie (kcal), often written as Calorie (capital C) on food labels, equals 1,000 small calories. Food energy is almost always stated in kcal.

Which calorie definition does this tool use?

This tool uses the thermochemical calorie: 1 cal = 4.184 J exactly. This is the most widely used definition in chemistry and physics.

Why would I convert calories to watt-hours?

Watt-hours are the standard unit for electrical energy (batteries, power grids). Converting lets you compare food energy intake against device consumption — for example, one 100 kcal snack provides about 116 Wh of energy.

Can I reverse this and convert watt-hours to calories?

Yes. Use the swap button or the reverse toggle to switch direction, then enter a value in Wh or kWh to get the calorie equivalent.

Calories to Watt Hours Converter

Name: Calories to Watt Hours Converter
Availability: InStock
Author: Nham Vu

Convert thermochemical calories (cal) or kilocalories (kcal) to watt-hours (Wh) and kilowatt-hours (kWh) instantly, with a quick-reference table.

Energy Converter

Input unit

cal (small) kcal (large)

Value

Watt-hours (Wh)

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Kilowatt-hours (kWh)

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Quick Reference Table

cal (small)	Wh	kcal (large)	kWh

Wh	cal (small)	kWh	kcal (large)

1 cal = 4.184 J • 1 Wh = 3,600 J • 1 cal ≈ 0.001162 Wh • 1 kcal ≈ 1.162 Wh

Summary

Convert thermochemical calories (cal) or kilocalories (kcal) to watt-hours (Wh) and kilowatt-hours (kWh) instantly, with a quick-reference table.

How it works

Select whether your input is in calories (cal) or kilocalories (kcal).
Type a number into the input field.
The converter instantly shows the result in both watt-hours and kilowatt-hours.
Click the swap button to reverse: convert Wh or kWh back to cal or kcal.
Scroll down to the reference table for quick look-ups of common values.

Use cases

Estimate how much electrical energy is equivalent to a food portion.
Cross-check battery capacity specs against caloric energy equivalents.
Physics or chemistry homework that mixes nutrition and electrical units.
Compare metabolic energy output to device power consumption.
Convert calorimeter measurements to watt-hour equivalents.
Understand energy density of foods in electrical terms.

Frequently Asked Questions

Last updated: 2026-07-01 · Reviewed by Nham Vu