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MJ
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What is a megajoule?

Used for fuel energy content and large-scale energy accounting

Definition

The megajoule equals 1,000,000 joules. Used for fuel energy content, large-scale mechanical work and in some European natural-gas billing. A litre of petrol contains about 34 MJ of energy.

Common uses

  • Fuel energy content reporting
  • Natural gas billing in some countries
  • Industrial energy consumption

🌍 Real-world scale

1 L petrol: ~34 MJ. 1 L diesel: ~38 MJ. Tesla Model 3 full charge: ~270 MJ.

Convert from megajoules

9 conversions
Megajoule to Joule1 MJ = 1,000,000 JMegajoule to Kilojoule1 MJ = 1,000 kJMegajoule to Kilowatt-Hour1 MJ = 0.2778 kWhMegajoule to Watt-Hour1 MJ = 277.778 WhMegajoule to Calorie1 MJ = 239,005.74 calMegajoule to Kilocalorie1 MJ = 239.006 kcalMegajoule to British Thermal Unit1 MJ = 947.817 BTUMegajoule to Electronvolt1 MJ = 6.2415e24 eVMegajoule to Therm1 MJ = 0.009478 thm

Convert to megajoules

9 conversions
Joule to Megajoule1 J = 1.0000e-6 MJKilojoule to Megajoule1 kJ = 0.001 MJKilowatt-Hour to Megajoule1 kWh = 3.6 MJWatt-Hour to Megajoule1 Wh = 0.0036 MJCalorie to Megajoule1 cal = 4.1840e-6 MJKilocalorie to Megajoule1 kcal = 0.004184 MJBritish Thermal Unit to Megajoule1 BTU = 0.001055 MJElectronvolt to Megajoule1 eV = 1.6022e-25 MJTherm to Megajoule1 thm = 105.506 MJ

Tips

  • 1 MJ = 1000 kJ = 0.278 kWh.
  • Natural gas heat content often quoted as MJ/m³.
  • For fuel economy, use MJ/km or L/100km interchangeably.

Common mistakes

  • Confusing MJ with MW (power).
  • Using MJ for electricity bills — kWh is standard.
  • Mixing fuel energy (MJ) with fuel volume (L) without unit conversion.

FAQ about the megajoule

What is a megajoule?
The megajoule equals 1,000,000 joules. Used for fuel energy content, large-scale mechanical work and in some European natural-gas billing. A litre of petrol contains about 34 MJ of energy.
Where is the megajoule used?
The megajoule is commonly used for: Fuel energy content reporting; Natural gas billing in some countries; Industrial energy consumption.
What is an example of a megajoule in real life?
1 L petrol: ~34 MJ. 1 L diesel: ~38 MJ. Tesla Model 3 full charge: ~270 MJ.
What category does the megajoule belong to?
The megajoule is a unit of energy, part of the 10-unit energy category on UnitConv.
How accurate are megajoule conversions?
All conversion factors follow NIST and BIPM international standards to 8 significant figures — the highest practical accuracy.
Explore all 10 energy units and their conversions.⚡ Energy hub →