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Convert megajoules to joules

1 MJ=1,000,000J

Use the converter below to change any megajoules value into joules instantly — with formula, conversion table, and real-world examples.

1,000,000

Conversion formula

Forward
joules = megajoules × 1,000,000
Reverse
megajoules = joules × 1.0000e-6

Example: 10 MJ × 1,000,000 = 10,000,000 J.

About both units

From

Megajoule

MJ

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.

Real-world: 1 L petrol: ~34 MJ. 1 L diesel: ~38 MJ. Tesla Model 3 full charge: ~270 MJ.
Read full megajoule reference →
To

Joule

J

The joule is the SI unit of energy, work and heat. Defined as one newton-metre or one watt-second. Named after James Prescott Joule who demonstrated the mechanical equivalent of heat. Lifting a 100 g apple 1 metre requires about 1 J.

Real-world: Lifting a 100 g apple 1 m: ≈ 1 J. 100 kcal snack: 418,400 J. Hand grenade: ~650 kJ.
Read full joule reference →

Megajoule to Joule conversion table

Common megajoules to joules values for quick reference.

Megajoule (MJ)Joule (J)
1 MJ1,000,000 J
10 MJ10,000,000 J
100 MJ100,000,000 J
500 MJ500,000,000 J
1,000 MJ1,000,000,000 J
5,000 MJ5,000,000,000 J
10,000 MJ10,000,000,000 J
50,000 MJ50,000,000,000 J
100,000 MJ100,000,000,000 J
500,000 MJ500,000,000,000 J

Tips & common mistakes

Quick 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.

Avoid these

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

Frequently asked questions

How many joules in a megajoule?
One megajoule equals 1,000,000 joules.
How do I convert megajoules to joules?
Multiply the megajoule value by 1,000,000 to get the equivalent in joules.
What is 100 megajoules in joules?
100 megajoules equals 100,000,000 joules.
Is a megajoule bigger than a joule?
Yes. 1 megajoule equals 1,000,000 joules, so one megajoule is larger.
How to convert megajoules to joules without a calculator?
Multiply by 1,000,000 for a quick estimate; use a calculator for precise results.

Related energy conversions

📊 See full comparison matrix →

More from Megajoule

MJ → kJ
1 = 1,000 kJ
MJ → kWh
1 = 0.2778 kWh
MJ → Wh
1 = 277.778 Wh
MJ → cal
1 = 239,005.74 cal
MJ → kcal
1 = 239.006 kcal
MJ → BTU
1 = 947.817 BTU
MJ → eV
1 = 6.2415e24 eV
MJ → thm
1 = 0.009478 thm

More to Joule

kJ → J
1 = 1,000 J
kWh → J
1 = 3,600,000 J
Wh → J
1 = 3,600 J
cal → J
1 = 4.184 J
kcal → J
1 = 4,184 J
BTU → J
1 = 1,055.06 J
eV → J
1 = 1.6022e-19 J
thm → J
1 = 105,505,585.3 J

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