Megajoules to Kilojoules Converter
Convert Megajoules (MJ) to Kilojoules (kJ) instantly, or use the conversion table below to look up common values.
Megajoules to Kilojoules conversion table
| Megajoules (MJ) | Kilojoules (kJ) |
|---|---|
| 1 | 1,000 |
| 2 | 2,000 |
| 3 | 3,000 |
| 4 | 4,000 |
| 5 | 5,000 |
| 10 | 10,000 |
| 25 | 25,000 |
| 50 | 50,000 |
| 100 | 100,000 |
How to convert Megajoules to Kilojoules
1 MJ equals 1,000 kJ. Use the converter above for any value, or read the table for common conversions.
kJ = MJ × 1000 · MJ = kJ × 0.001Multiply a megajoules figure by 1,000 to get kilojoules, or divide it by 0.001 to go the other way.
Worked examples
- 1 MJ= 1,000 kJ
- 5 MJ= 5,000 kJ
- 10 MJ= 10,000 kJ
- 100 MJ= 100,000 kJ
- 500 MJ= 500,000 kJ
What these units are
Megajoules (MJ). A megajoule is 1,000 kilojoules, or about 0.278 kilowatt-hours. It is used for the energy content of fuels: a litre of diesel holds roughly 36 megajoules.
Kilojoules (kJ). A kilojoule is 1,000 joules. It is used for food energy in most countries outside the United States, and for small industrial figures.
All factors are exact definitions, so only the display is rounded.
Converting Megajoules to Kilojoules in practice
Working in megajoules
One megajoule is 1,000 kilojoules, which is one million joules. Fuels, industrial processes and large energy figures are quoted in megajoules when a count in joules would be unwieldy.
Fuel energy content, blast energy, industrial process heat and large-scale storage are described in megajoules. Engineering calculations for combustion and materials testing also use the unit.
Multiplying a power figure in kilowatts by a duration in seconds produces joules, and a thousand of those make one megajoule. One kilowatt-hour is exactly 3.6 megajoules, the same energy under another name.
The frequent confusion is to treat a megawatt of capacity as a megawatt-hour of energy, and the same slip appears with megajoules when a rate is read as an amount. Time is the missing factor.
Megajoules and kilojoules differ only by a factor of one thousand, while the kilowatt-hour names the same energy at exactly 3.6 megajoules. Fuel data is tabulated in megajoules, electricity accounting uses kilowatt-hours, and mechanics works in joules.
Reading the result in kilojoules
One kilojoule is exactly 1,000 joules, and the symbol is kJ. It is the joule multiple that food packaging commonly prints, with energy shown in kilojoules beside kilocalories, and chemistry uses it for reaction energies.
Nutrition panels, exercise machines and dietary advice report energy in kilojoules wherever the metric system is used. Materials and fuel data, such as energy content per kilogram, are tabulated in kilojoules as well.
The step from kilojoules to megajoules divides by exactly one thousand, so nothing is lost in the conversion. One kilocalorie equals 4.184 kilojoules, which is how the two columns on a food label correspond.
A reader who compares a kilojoule figure with a kilocalorie figure as though they were the same number will misjudge the energy by more than four times. The label's two columns state one amount in two units.
Kilojoules and kilocalories are the two energy columns on a food label, and the kilojoule figure is the larger number because one kilocalorie is 4.184 kilojoules. Megajoules take over where kilojoule figures become long, as they do for fuels.
Checking a megajoules to kilojoules conversion
Energy units are defined against the joule, so every conversion in this dimension is a single exact multiplication by a published number rather than a chain of steps that could accumulate error.
The pair that needs care is the kilowatt-hour, because it looks like a power unit and is not. It is a watt sustained for an hour, which is why an electricity meter counts in kilowatt-hours while a generator is rated in kilowatts: one is an amount, the other is a rate, and only a duration links them.
To check an energy conversion, express both sides in joules or both in kilowatt-hours before comparing. The commonest mistake is treating a food calorie as a calorie when the label means a kilocalorie, which understates the figure a thousandfold.
Tanzania reference points
Real quantities, converted into the units on this page.
One unit of electricity on a Tanzanian prepaid meter
1 kWh = 3.6 MJ = 3,600 kJ
The average domestic rate was about 229.59 TZS per kWh as of December 2025, including taxes and supply. That is an average across domestic customers, not the marginal rate on a bill.
Source: GlobalPetrolPrices — Tanzania electricity prices (compiled from EWURA/TANESCO tariffs) · verified 2026-09-14
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