Convert kilowatt-hour to kilojoule.
kWh to kJ — formula, reference values, and a live converter.
Convert kilowatt-hour (kWh) to kilojoule (kJ). This is a fixed-ratio conversion — multiply the input by the factor below.
Formula
kJ = kWh × 3600
Reference values
| kWh (kilowatt-hour) | kJ (kilojoule) |
|---|---|
| 0.1 kWh | 360 kJ |
| 0.5 kWh | 1800 kJ |
| 1 kWh | 3600 kJ |
| 2 kWh | 7200 kJ |
| 5 kWh | 18000 kJ |
| 10 kWh | 36000 kJ |
| 50 kWh | 1.8e+05 kJ |
| 100 kWh | 3.6e+05 kJ |
Things to watch for
- The 'calorie' in nutrition labels is actually a kilocalorie (kcal, sometimes Cal with capital C). A '200 calorie' candy bar is 200 kcal = 836 kJ.
- 1 kWh = 3.6 MJ (exactly). Used for billing electricity.
- Electron-volts (eV) are convenient at atomic/molecular scales; joules at human scales; kWh at building scales.
What is a kilowatt-hour?
One kilowatt-hour equals 3,600,000 joules — the energy consumed at 1 kW of power for 1 hour. Electricity billing (a typical US home uses around 30 kWh/day), EV batteries, and large-scale energy.
What is a kilojoule?
One kilojoule equals exactly 1,000 joules. Food energy labels in Europe and Australia (an apple is about 200 kJ), thermal calculations.
What does kWh look like in everyday objects?
To put the unit in perspective, here are a few real-world examples.
- 1 kWh — running a 1000 W microwave for one hour.
- 30 kWh — a typical US home's daily electricity use.
- 70 kWh — a Tesla Model 3 long-range battery.
How to convert kilowatt-hour to kilojoule
To convert a value from kilowatt-hour (kWh) to kilojoule (kJ), apply the conversion factor shown in the formula above. The calculation is the same whether you do it by hand, in a spreadsheet, or with the live converter on this page.
Steps:
- Take your input value in kWh.
- Apply the formula
kJ = kWh × 3600. - The result is your value in kJ.
For repeated calculations, save the formula in a spreadsheet or use the live converter at the top of this page — it handles the math automatically and displays the result as you type.
Frequently asked questions
How do I convert kWh to kJ?
Apply the formula kWh → kJ shown above, or just type your value into the converter at the top of this page. The result updates instantly.
Which is bigger, kWh or kJ?
This depends on the conversion ratio in the formula. If the factor multiplied by your value gives a larger number, then kJ is the smaller unit (so it takes more of them to express the same quantity). If the result is smaller, then kJ is the larger unit.
When would I use kWh versus kJ?
Both units measure energy, so the choice depends on context. Kilowatt-hour is typically used for food labeling, batteries, fuel, and electric utility billing; kilojoule similarly. Most professional fields standardize on one or the other based on regional conventions or technical tradition.
How precise is this kWh to kJ conversion?
The conversion factor shown is the internationally defined exact value (or the best-published approximation if the relationship is irrational, like degrees-to-radians). The live converter on this page uses double-precision floating-point math, accurate to about 15 significant digits — far beyond any practical engineering need.
Is the conversion ratio exact, or an approximation?
Most unit conversions between SI metric units, and between SI and US customary units, have been formally defined as exact values since the 1959 international yard-pound agreement and subsequent SI redefinitions. Exceptions are unit pairs that involve irrational numbers (radians, e.g.) or empirical conversions (like food calories, which depend on temperature). When in doubt, consult the formula at the top of this page.
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