Energy converter
Joules to Kilowatt-hours
Converting Joules to Kilowatt-hours is a single multiplication when you know the factor. One J equals 2.7778e-07 kWh, so multiply the value in J by 2.7778e-07. The calculator below works in both directions and accepts decimals.
Formula 1 J = 2.7778e-07 kWh
Need the other direction? Kilowatt-hours to Joules.
How to convert Joules to Kilowatt-hours
The joule is the SI unit of energy, equal to one newton-metre. A kilowatt-hour is 3.6 megajoules and is the unit on electricity bills.
To convert Joules to Kilowatt-hours, multiply the value in J by 2.7778e-07. For example, 10 J × 2.7778e-07 = 2.7778e-06 kWh. This works because the ratio between the two units is constant for every value in energy.
Worked examples
| J | kWh |
|---|---|
| 1 J | 2.7778e-07 kWh |
| 2.5 J | 6.9444e-07 kWh |
| 5 J | 1.3889e-06 kWh |
| 10 J | 2.7778e-06 kWh |
| 25 J | 6.9444e-06 kWh |
| 50 J | 1.3889e-05 kWh |
| 100 J | 2.7778e-05 kWh |
Reverse conversion
| kWh | J |
|---|---|
| 1 kWh | 3,600,000 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 |
When this conversion is useful
This is the calculation you need when you are comparing a nutrition label, an electricity bill or a heating system. Because the factor is fixed, you can use the same number for a single measurement or for a batch: 1,000 J is 2.7778e-04 kWh.
Is the conversion exact?
Yes for practical use: the factors come from international definitions, with rounding applied only for display.
Reference: BIPM SI Brochure and NIST SP 811. Last reviewed: 2026-11-01.
J to kWh conversion chart
The chart lists the most requested values. For a value that is not here, use the converter at the top of the page.
| Joules (J) | Kilowatt-hours (kWh) |
|---|---|
| 1 J | 2.7778e-07 kWh |
| 2 J | 5.5556e-07 kWh |
| 3 J | 8.3333e-07 kWh |
| 4 J | 1.1111e-06 kWh |
| 5 J | 1.3889e-06 kWh |
| 6 J | 1.6667e-06 kWh |
| 7 J | 1.9444e-06 kWh |
| 8 J | 2.2222e-06 kWh |
| 9 J | 2.5000e-06 kWh |
| 10 J | 2.7778e-06 kWh |
| 11 J | 3.0556e-06 kWh |
| 12 J | 3.3333e-06 kWh |
| 13 J | 3.6111e-06 kWh |
| 14 J | 3.8889e-06 kWh |
| 15 J | 4.1667e-06 kWh |
| 16 J | 4.4444e-06 kWh |
| 17 J | 4.7222e-06 kWh |
| 18 J | 5.0000e-06 kWh |
| 19 J | 5.2778e-06 kWh |
| 20 J | 5.5556e-06 kWh |
| 21 J | 5.8333e-06 kWh |
| 22 J | 6.1111e-06 kWh |
| 23 J | 6.3889e-06 kWh |
| 24 J | 6.6667e-06 kWh |
| 25 J | 6.9444e-06 kWh |
| 26 J | 7.2222e-06 kWh |
| 27 J | 7.5000e-06 kWh |
| 28 J | 7.7778e-06 kWh |
| 29 J | 8.0556e-06 kWh |
| 30 J | 8.3333e-06 kWh |
| 31 J | 8.6111e-06 kWh |
| 32 J | 8.8889e-06 kWh |
| 33 J | 9.1667e-06 kWh |
| 34 J | 9.4444e-06 kWh |
| 35 J | 9.7222e-06 kWh |
| 36 J | 1.0000e-05 kWh |
| 37 J | 1.0278e-05 kWh |
| 38 J | 1.0556e-05 kWh |
| 39 J | 1.0833e-05 kWh |
| 40 J | 1.1111e-05 kWh |
| 41 J | 1.1389e-05 kWh |
| 42 J | 1.1667e-05 kWh |
| 43 J | 1.1944e-05 kWh |
| 44 J | 1.2222e-05 kWh |
| 45 J | 1.2500e-05 kWh |
| 46 J | 1.2778e-05 kWh |
| 47 J | 1.3056e-05 kWh |
| 48 J | 1.3333e-05 kWh |
| 49 J | 1.3611e-05 kWh |
| 50 J | 1.3889e-05 kWh |
| 60 J | 1.6667e-05 kWh |
| 70 J | 1.9444e-05 kWh |
| 80 J | 2.2222e-05 kWh |
| 90 J | 2.5000e-05 kWh |
| 100 J | 2.7778e-05 kWh |
Frequently asked questions
How many Kilowatt-hours are in 1 Joules?
1 J equals 2.7778e-07 kWh.
How do I convert Joules to Kilowatt-hours?
Multiply the J value by 2.7778e-07. Example: 25 J = 6.9444e-06 kWh.
What is 2.5 J in kWh?
2.5 J = 6.9444e-07 kWh.
Is the J to kWh conversion exact?
Yes for practical use: the factors come from international definitions, with rounding applied only for display.
Does the calculator work offline?
Yes. The conversion runs in your browser with JavaScript, so it works after the page has loaded, even without a connection.