joules to watt-hours
Convert joule to watt-hour — instant, free, with the formula shown.
1 J=0.000278 Wh
How to convert joule to watt-hour
To convert joule to watt-hour, multiply by 0.00027778:
Wh = J × 0.00027778
For example, 10 J × 0.000278 = 0.002778 Wh.
J to Wh conversion table
| joules (J) | watt-hours (Wh) |
|---|---|
| 1 J | 0.000278 Wh |
| 2 J | 0.000556 Wh |
| 5 J | 0.001389 Wh |
| 10 J | 0.002778 Wh |
| 25 J | 0.006944 Wh |
| 50 J | 0.013889 Wh |
| 100 J | 0.027778 Wh |
| 250 J | 0.069444 Wh |
| 500 J | 0.138889 Wh |
| 1000 J | 0.277778 Wh |
Other joule conversions
Convert to watt-hour from another unit
J to Wh — frequently asked
How many watt-hours are in 1 joule?
1 joule = 0.000278 watt-hours (J × 0.000278 = Wh).
What is the formula to convert joule to watt-hour?
Multiply your joule value by 0.00027778 to get watt-hour.
How do I convert 10 joules to watt-hours?
10 J = 0.002778 Wh. For 100 J the answer is 0.027778 Wh. Use the calculator on this page for any other value.
When to convert joule to watt-hour
1Electricity bills (kWh)
2Nutrition labels (kcal / food cal)
3HVAC and heating (BTU, therms)
4Physics and chemistry (J, eV)
Energy conversion — common questions
Is a food calorie the same as a calorie?
No — a food 'Calorie' (capital C) actually means 1 kilocalorie = 1,000 small calories = 4,184 J. Nutrition labels typically write 'cal' meaning kcal.
How many joules in 1 kWh?
1 kWh = 3,600,000 J (3.6 MJ). Because 1 kW × 1 hour = 1,000 W × 3,600 s = 3,600,000 J.
What is a BTU?
British Thermal Unit — the energy required to raise 1 pound of water by 1 °F. 1 BTU ≈ 1,055 J.
Related calculators & tools
Compound Interest Calculator
SIP, FD, and investment returns
BMI Calculator
Body Mass Index with Asian thresholds
Calorie Calculator
Daily intake, TDEE & macros
Loan EMI Calculator
Home, car & personal loan EMI
Caffeine Half-Life Calculator
How long caffeine stays in your system
Percentage Calculator
Convert marks to percentage