Convert energy units — joules, kilowatt-hours, calories, BTU, electron volts and more.
| Unit | Name | Value |
|---|---|---|
| 0.001 MJ | 0.000277778 kWh | |
| 0.01 MJ | 0.00277778 kWh | |
| 0.1 MJ | 0.0277778 kWh | |
| 1 MJ | 0.277778 kWh | |
| 5 MJ | 1.38889 kWh | |
| 10 MJ | 2.77778 kWh | |
| 50 MJ | 13.8889 kWh | |
| 100 MJ | 27.7778 kWh | |
| 1000 MJ | 277.778 kWh |
Formula: Kilowatt-Hour = Megajoule × 0.2778
Multiply any megajoule value by 0.2778 to get kilowatt-hour.
Reverse: Megajoule = Kilowatt-Hour × 3.6
Common megajoule values — factor: 1 MJ = 0.2778 kWh
| Megajoule (MJ) | Kilowatt-Hour (kWh) | Context |
|---|---|---|
| 0.001 MJ | 0.0002778 kWh | 1 kJ |
| 0.01 MJ | 0.002778 kWh | 10 kJ |
| 0.1 MJ | 0.02778 kWh | 100 kJ |
| 1 MJ | 0.2778 kWh | 1 MJ |
| 3.6 MJ | 1 kWh | 1 kWh |
| 10 MJ | 2.778 kWh | 10 kWh |
| 34 MJ | 9.444 kWh | 1L petrol |
| 100 MJ | 27.78 kWh | ~28 kWh |
| 360 MJ | 100 kWh | 100 kWh |
| 1,000 MJ | 277.8 kWh | ~278 kWh |
| 4,600 MJ | 1,278 kWh | 1 tonne TNT |
| 1e+04 MJ | 2,778 kWh | ~2.8 MWh |
| 1e+05 MJ | 2.778e+04 kWh | ~28 MWh |
| 1e+06 MJ | 2.778e+05 kWh | ~278 MWh |
| 1.000e+09 MJ | 2.778e+08 kWh | ~278 GWh |
MJ ÷ 3.6 = kWh. Exact.
One kilowatt-hour = exactly 3.6 megajoules.
kWh × 3.6 = MJ.
Measures fuel energy content — 1 liter of petrol ≈ 34 MJ.
Compares battery pack energy in MJ and kWh for range calculations.
Quantifies explosive yield — 1 kg TNT ≈ 4.6 MJ.
Calculates daily/annual energy yield of solar and wind in MJ.
Compares fuel energy costs across transport modes in MJ/km.
Models annual heating and cooling energy demand in MJ.
The megajoule (MJ) equals 1,000,000 joules and is used for large-scale energy measurements in engineering, transportation, and industrial processes.
One liter of petrol contains about 34 MJ of chemical energy. A bolt of lightning releases about 1-5 MJ. An adult's daily food intake is roughly 8-10 MJ. Electric vehicle batteries are typically rated at 40-100 MJ (11-28 kWh).
Interesting fact: The kinetic energy of a 1,000 kg car traveling at 100 km/h is about 0.385 MJ. TNT explosive releases about 4.6 MJ per kilogram when detonated.
The kilowatt-hour (kWh) is the commercial unit of electrical energy, equal to the energy consumed by a 1,000-watt appliance in one hour (3,600,000 joules). It became standard with the growth of the electrical grid in the late 19th century.
Electricity bills worldwide are denominated in kWh. A typical household uses 300–1,000 kWh per month. An electric car uses about 15–25 kWh per 100 km. Solar panels generate 250–400 kWh per year per panel.
Interesting fact: The average price of electricity in the US is about $0.12 per kWh. One kWh can run a 100W light bulb for 10 hours, charge a smartphone about 100 times, or power a laptop for 2-3 days.
Converting megajoule to kilowatt-hour is common across energy, nutrition, engineering, and science. Different sectors use different energy units — joules in physics, kcal in nutrition, kWh in electricity, and BTU in HVAC — making accurate conversion essential for cross-disciplinary work and international comparisons.
Quick reference: 5 MJ = 1.389 kWh and 10 MJ = 2.778 kWh. Reverse: 1 kWh = 3.6 MJ. Exact factor: 1 MJ = 0.2778 kWh.
All conversions use IEEE 754 double-precision arithmetic, accurate to at least 8 significant figures.