How many kilocalories are in 1 watt-hour?

1 watt-hour equals 3600 ÷ 4184 ≈ 0.859845 kcal. This follows from 1 Wh = 3600 J and 1 thermochemical kcal = 4184 J.

Is a food Calorie the same as a kilocalorie?

Yes. On US nutrition labels, "Calories" (capital C) means kilocalories (kcal). 1 food Calorie = 1 kcal ≈ 1.16222 Wh.

How many watt-hours is 2000 kcal (a typical daily diet)?

2000 kcal × (4184/3600) ≈ 2324.4 Wh or 2.324 kWh. A US household uses about 30 kWh per day, so the human body runs on roughly 8% of typical household energy.

How do I convert kcal back to watt-hours?

Multiply kilocalories by 4184/3600 ≈ 1.16222. For example, 100 kcal × 1.16222 ≈ 116.2 Wh.

Why is the factor 3600/4184 and not a round number?

The thermochemical kilocalorie is defined as exactly 4184 joules. One watt-hour is exactly 3600 joules. Dividing gives 3600/4184 ≈ 0.859845 — an irrational ratio because the two units were defined independently.

Watt Hours to Kilocalories Converter

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

Enter watt-hours and instantly get kilocalories (kcal) and food Calories (Cal). Reverse converter and reference table included.

Watt-hours → Kilocalories

Enter a value in Wh to see the kilocalorie equivalent.

Watt-hours (Wh)

Quick:

Results will appear here once you enter a value.

Kilocalories → Watt-hours

Enter a value in kcal for the reverse conversion.

Kilocalories (kcal)

Quick:

Results will appear here once you enter a value.

Quick-Reference Table

Watt-hours (Wh)	Kilocalories (kcal)	Food Calories (Cal)	Common reference
1 Wh	0.8598 kcal	0.8598 Cal	Small LED bulb, 6 min
10 Wh	8.598 kcal	8.598 Cal	Phone screen, 1 hour
100 Wh	85.98 kcal	85.98 Cal	Small power bank
500 Wh	429.9 kcal	429.9 Cal	Laptop battery (typical)
1000 Wh	859.8 kcal	859.8 Cal	1 kWh (utility unit)

Factor: 1 Wh = 3600 J ÷ 4184 J/kcal = 0.859845 kcal (exact thermochemical definition). 1 food Calorie (Cal) = 1 kcal.

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Summary

Enter watt-hours and instantly get kilocalories (kcal) and food Calories (Cal). Reverse converter and reference table included.

How it works

Enter a watt-hour (Wh) value in the top input field.
The tool multiplies by 3600/4184 (≈ 0.859845) to get kilocalories.
One food Calorie (Cal) equals one kilocalorie (kcal), so the kcal result doubles as the Cal value.
Use the reverse section to convert from kilocalories back to watt-hours.
Check the quick-reference table for common Wh-to-kcal benchmarks.

Use cases

Compare battery capacity (Wh) to food energy (kcal) for survival or off-grid planning.
Convert EV or device energy use from watt-hours to dietary calorie equivalents.
Calculate how many food Calories a battery bank could theoretically store.
Verify engineering calculations that mix electrical and nutritional energy units.
Convert workout calorie burns between fitness trackers and electrical energy storage units.
Teach the relationship between electrical and nutritional energy in physics or biology.

Frequently Asked Questions

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