Convert kWh to joules
Convert kWh to joules instantly. 1 kWh = 3,600,000 J. Formula, worked examples and a quick reference table.
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One kilowatt-hour equals 3,600,000 joules. To convert any number of kilowatt-hours to joules, multiply by 3,600,000.
The converter above works in both directions and updates as you type. Below you will find the formula, a worked example and a reference table of common values.
Energy conversions sit between physics and the kitchen. The joule is the SI unit and the one every equation uses; the calorie survives on food labels, where it is actually a kilocalorie a thousand times larger than the physicist’s calorie; and the kilowatt-hour is what an electricity meter counts. All three measure the same quantity, which is why an appliance’s consumption and a meal’s energy content can, in principle, be compared directly.
kWh to joules formula
To go the other way, use kilowatt-hour = joule ÷ 3,600,000.
About these units
The kilowatt-hour is the unit electricity is billed in worldwide: one kilowatt drawn for one hour, or 3.6 megajoules.
The joule is the SI unit of energy: one newton acting over one metre, or one watt for one second. Every other energy unit here is defined against it.
Kilowatt-hour is also written kilowatt hours and units of electricity. Joule is also written joules.
Sources
kWh to joules conversion table
| Kilowatt-hour | Joule |
|---|---|
| 1 kWh | 3,600,000 J |
| 2 kWh | 7,200,000 J |
| 3 kWh | 10,800,000 J |
| 5 kWh | 18,000,000 J |
| 10 kWh | 36,000,000 J |
| 20 kWh | 72,000,000 J |
| 25 kWh | 90,000,000 J |
| 50 kWh | 180,000,000 J |
| 100 kWh | 360,000,000 J |
| 250 kWh | 900,000,000 J |
| 500 kWh | 1,800,000,000 J |
| 1,000 kWh | 3,600,000,000 J |
Frequently asked questions
How many joules are in a kilowatt-hour? +
There are 3,600,000 joules in one kilowatt-hour.
What is 10 kWh in J? +
10 kWh equals 36,000,000 J. Multiply 10 by 3,600,000.
How do I convert joule back to kilowatt-hour? +
Use kilowatt-hour = joule ÷ 3,600,000. The converter above handles both directions, or see our dedicated joules to kWh page.
How accurate is this kilowatt-hour to joule conversion? +
The factor used is 3,600,000, carried at full double precision. Where a unit has an exact legal definition the factor is exact rather than approximate. Rounding is applied only to the displayed result, so the answer is never a calculation done on an already-rounded number.
Is there a quick way to estimate kWh to J in my head? +
The factor is exactly 3,600,000, which is short enough to apply directly without an approximation.