Enter gigajoules or megawatt-hours into the calculator to convert to the other value.

GJ to MWh Conversion Calculator

Enter exactly 1 value to calculate the other

Assumptions Assumptions
  • Conversions are energy-to-energy only; no fuel heating value assumptions (HHV/LHV) are applied.
  • SI units are used with joules as the base: 1 Wh = 3600 J; 1 kWh = 3.6×106 J; 1 MWh = 3.6×109 J; 1 GJ = 109 J.
  • Results are rounded for readability; use the calculator for higher precision.
  • No power rates are implied—megawatt-hours (MWh) and gigajoules (GJ) are both energy, not power.
When to Use This Calculator
  • Converting utility bills or energy reports between natural gas (GJ) and electricity (MWh).
  • Normalizing energy usage across sites or datasets using different units.
  • Engineering and academic problems requiring consistent SI energy units.
Input Definitions
  • Gigajoules — choose GJ, MJ, kJ, J, TJ, or PJ.
  • Megawatt-hours — choose MWh, kWh, Wh, or GWh.
  • Conversions — MWh = GJ ÷ 3.6; GJ = MWh × 3.6; using J as the base unit.

GJ to MWh Formula

The following formulas convert gigajoules to megawatt-hours and back using SI units with joules as the base quantity.

\mathrm{MWh} = \frac{\mathrm{GJ}}{3.6}
  • 1 MWh = 3.6 GJ
  • 1 GJ = 1×109 J
  • 1 kWh = 3.6×106 J
  • 1 Wh = 3,600 J.

GJ to MWh Conversion Table

Gigajoules (GJ) to Megawatt-hours (MWh)
GJ MWh
0.10.028
0.250.069
0.50.139
0.750.208
10.278
1.50.417
20.556
2.50.694
30.833
41.111
51.389
7.52.083
102.778
123.333
154.167
205.556
256.944
5013.889
7520.833
10027.778
* SI relationship: 1 MWh = 3.6 GJ (i.e., MWh = GJ ÷ 3.6).

How do you convert GJ to MWh? Divide gigajoules by 3.6 to get megawatt-hours.

How do you convert MWh to GJ? Multiply megawatt-hours by 3.6 to get gigajoules.

Example Problem

Convert 12 GJ to MWh.

Use the formula: MWh = GJ ÷ 3.6.

MWh = 12 ÷ 3.6 = 3.333 MWh