Kilowatt Hours to Joules Converter

Kilowatt Hours to Joules

Convert kilowatt hours (kWh) to joules (J). Both measure work and power, and the conversion comes up in nutrition, electricity, fitness work.

The Formula

`` joules = kilowatt hours × 3600000 kilowatt hours = joules × 2.77777777778e-7 `

One kilowatt hour is 3,600,000 joules, and one joule is 2.7778e-7 kilowatt hours.

Conversion Table

Kilowatt Hours	Joules
1 kWh	3,600,000 J
2 kWh	7,200,000 J
5 kWh	18,000,000 J
10 kWh	36,000,000 J
25 kWh	90,000,000 J
50 kWh	180,000,000 J
100 kWh	360,000,000 J
500 kWh	1,800,000,000 J
1,000 kWh	3,600,000,000 J

The Other Direction

Joules	Kilowatt Hours
1 J	2.7778e-7 kWh
2 J	5.5556e-7 kWh
5 J	1.3889e-6 kWh
10 J	2.7778e-6 kWh
25 J	6.9444e-6 kWh
50 J	1.3889e-5 kWh
100 J	2.7778e-5 kWh
500 J	1.3889e-4 kWh
1,000 J	2.7778e-4 kWh

What Each Unit Is

Kilowatt Hours (kWh) — 1,000 watt-hours, or 3.6 million joules. The unit electricity has been billed in since metering began.

Joules (J) — the work done by one newton acting over one metre — the SI derived unit of energy. Named for James Prescott Joule, who established the mechanical equivalent of heat.

A Sense of Scale

• A home uses 8–30 kWh a day
• An EV takes 15–20 kWh per 100 km
• Lifting an apple one metre takes about 1 J
• A heartbeat uses roughly 1 J

Precision

The factor 3600000 is rounded. For engineering work carry more digits than the table above, and round only at the end — rounding at each step compounds.

In Code

`javascript const kilowattHourToJoule = (value) => value * 3600000; ``

Where This Conversion Comes Up

• Nutrition
• Electricity
• Fitness
• Heating
• Fuel

How Many Decimals Do You Need?

Rounding the factor costs accuracy, and how much depends on the factor. Converting 137 kWh with the factor truncated at each decimal place:

Decimals kept	Factor	137 kWh becomes	Error
0	3600000	493,200,000	—
1	3600000	493,200,000	—
2	3600000	493,200,000	—
3	3600000	493,200,000	—
4	3600000	493,200,000	—

A rule that holds for any conversion: round once, at the end. Rounding the factor and then multiplying compounds the error through every subsequent calculation, while carrying full precision and rounding the final answer does not.

The right number of significant figures is set by your input, not by the converter. If you measured kilowatt hours to three significant figures, the answer in joules is only good to three — writing more digits claims precision the measurement never had.