How many Joules are in 1 Kilowatt-hour (kWh)?

1 Kilowatt-hour (kWh) equals exactly 3,600,000 Joules (3.6 Megajoules). It represents the energy consumed by a 1,000-watt appliance running for one hour.

What is the difference between a food Calorie (kcal) and a scientific calorie (cal)?

1 dietary 'Calorie' (capital C) on food labels is actually a Kilocalorie (kcal), equaling 1,000 scientific small calories (cal) or 4,184 Joules.

How many BTU are in 1 kWh?

1 Kilowatt-hour equals approximately 3,412.14 British Thermal Units (BTU).

What is the SI unit of energy?

The official SI unit of energy and work is the Joule (J), defined as the work done by a force of one Newton moving an object through a distance of one meter (1 N·m = 1 kg·m²/s²).

Converters

Energy Converter

Convert energy units between Joules, Kilojoules, Calories, Kilocalories, Watt-hours, kWh, BTU, and eV.

Quick Answer & Summary

An energy converter recalculates work, heat, and electrical power units across Joules (J), Kilojoules (kJ), Calories (cal), Kilocalories/food calories (kcal), Kilowatt-hours (kWh), BTU, and Electron Volts (eV). 1 kWh = 3.6 Million Joules, and 1 food Calorie (kcal) = 4,184 Joules.

Key Energy Unit Conversions

1 kWh = 3.6×10⁶ J = 3412.14 BTU | 1 kcal = 4184 J = 1000 cal | 1 eV = 1.602176634×10⁻¹⁹ J

Anchored to the SI base unit of work and energy: the Joule (J).

From

Result

3,600,000

1 Kilowatt-hours = 3,600,000 Joules

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Updated: August 2026

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Documentation & Guide

How to Use Energy Converter

Input Energy Quantity

Type the numerical energy, work, or heat value into the 'From' box.

Select Energy Units

Pick starting unit (such as Kilowatt-hours for electricity) and target unit (such as Joules or BTU).

Instant Conversion

The converted energy value is computed instantly with precise scientific notation support.

Pro Tips

Use 1 kcal = 4.184 kJ for nutritional diet conversions

12,000 BTU/hr equals a 1-ton air conditioning unit

Practical Examples & Conversions

Input

1 kWh

Output

3,600,000 J (3.6 MJ)

Frequently Asked Questions (PAA)

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Authoritative Standards & Citations

Calculations and algorithms on this page are implemented and verified in strict accordance with the following official technical specifications:

National Institute of Standards and Technology

NIST Special Publication 811: Guide for the Use of the International System of Units (SI)

Authoritative metric, imperial, and astronomical unit conversion factors.

Bureau International des Poids et Mesures

BIPM: The International System of Units (SI Brochure)

The definitive global reference for base and derived scientific measurement units.