How many calories are in one watt-hour?

One watt-hour (Wh) equals approximately 860.42 thermochemical calories (cal). This comes from 3,600 joules per watt-hour divided by 4.184 joules per calorie.

How many kilocalories are in one kilowatt-hour?

One kilowatt-hour (kWh) equals approximately 860.42 kilocalories (kcal). The ratio is the same at both scales: 3,600,000 J ÷ 4,184 J/kcal ≈ 860.42 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.

Is a kilocalorie the same as a food Calorie?

Yes. The Calorie shown on nutrition labels (capital C) is a kilocalorie (kcal) — 1,000 small thermochemical calories. So 1 Wh ≈ 0.86 food Calories.

Why would I compare watt-hours to calories?

It is useful when thinking about human energy output versus device power, or when comparing battery capacity to food energy. For example, a 100 Wh laptop battery stores about 86,042 cal — roughly the energy in 20 grams of fat.

Watt Hours to Calories Converter

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

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

Wh / kWh → cal / kcal

Result

Enter a value and click Convert.

Quick Reference Table

1 Wh = 860.4206 cal | 1 kWh = 860,420.6 cal = 860.42 kcal

Watt-hours (Wh)	Calories (cal)	Kilocalories (kcal)

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Summary

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

How it works

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

Use cases

Estimate how many calories are stored in a battery or power bank.
Cross-check electrical energy consumption against dietary energy equivalents.
Physics or chemistry coursework mixing electrical and thermal energy units.
Compare power device ratings to food calorie values.
Convert calorimeter results expressed in watt-hours to calorie equivalents.
Understand energy density of batteries in nutritional terms.

Frequently Asked Questions

Last updated: 2026-07-23 · Reviewed by Nham Vu