Kilowatt-hours to Megajoules Converter

1 kWh equals 3.6 MJ, and 1 MJ equals 0.27777778 kWh. Enter a value in either box to convert kilowatt-hours to megajoules and back. Formula: joules = value x unit factor (1 cal = 4.184 J, 1 Wh = 3,600 J, 1 BTU(IT) = 1,055.05585262 J, 1 eV = 1.602176634e-19 J).

· CalcFlow Editorial

1 kWh = 3.6 MJ

Results shown are estimates for informational purposes only. Nothing on CalcFlow is financial, tax, legal, or medical advice. Always consult a qualified professional before making important decisions.

Kilowatt-hours to Megajoules Conversion Table

Kilowatt-hoursMegajoules
1 kWh3.6 MJ
2 kWh7.2 MJ
5 kWh18 MJ
10 kWh36 MJ
50 kWh180 MJ
100 kWh360 MJ
500 kWh1,800 MJ
1,000 kWh3,600 MJ
2,000 kWh7,200 MJ

Megajoules to Kilowatt-hours Conversion Table

MegajoulesKilowatt-hours
1 MJ0.27777778 kWh
2 MJ0.55555556 kWh
5 MJ1.3888889 kWh
10 MJ2.7777778 kWh
50 MJ13.888889 kWh
100 MJ27.777778 kWh
500 MJ138.88889 kWh
1,000 MJ277.77778 kWh
2,000 MJ555.55556 kWh

Worked example: 10 kWh = 36 MJ. A 2,000 kcal day is 2,000 x 4.184 = 8,368 kJ. Running a 1.5 kW heater for 2 hours uses 3 kWh, which is 10.8 MJ.

Need other units? Open the full Energy Converter.

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Formula

joules = value x unit factor (1 cal = 4.184 J, 1 Wh = 3,600 J, 1 BTU(IT) = 1,055.05585262 J, 1 eV = 1.602176634e-19 J)

Understanding Energy Conversion

Energy is measured in joules in the SI system. Electricity bills use kilowatt-hours, nutrition labels use kilocalories (called Calories on food packaging), and heating equipment is often rated in BTU. The thermochemical calorie is exactly 4.184 joules, so one food Calorie (a kilocalorie) is 4,184 joules. The electronvolt, now exactly defined, is used for particles and atoms.

Tips and Best Practices

  • 1One kilowatt-hour equals 3.6 megajoules, or about 3,412 BTU.
  • 2A food Calorie with a capital C is a kilocalorie, or 4.184 kJ.
  • 3Divide kilojoules by 4.184 to get kilocalories.

Real-World Example

A 2,000 kcal day is 2,000 x 4.184 = 8,368 kJ. Running a 1.5 kW heater for 2 hours uses 3 kWh, which is 10.8 MJ.

Common Mistakes to Avoid

  • Mixing calories (cal) with kilocalories (kcal); there is a factor of 1,000.
  • Confusing kilowatts (power) with kilowatt-hours (energy).
  • Using a different BTU definition than the one you are comparing with; several exist.

How to Use

  1. Type a number in the Kilowatt-hours box.
  2. The Megajoules result appears instantly; you can also edit the Megajoules box to convert backwards.
  3. Use the swap button to reverse the direction and Copy result to copy the answer.

Frequently Asked Questions

Q

How many megajoules are in 1 kWh?

1 kWh equals 3.6 MJ.
Q

How many kilowatt-hours are in 1 MJ?

1 MJ equals 0.27777778 kWh.
Q

What is the formula to convert kilowatt-hours to megajoules?

joules = value x unit factor (1 cal = 4.184 J, 1 Wh = 3,600 J, 1 BTU(IT) = 1,055.05585262 J, 1 eV = 1.602176634e-19 J).
Q

How many BTU are in a kWh?

One kilowatt-hour is about 3,412.14 BTU (International Table).

Sources: NIST SP 811 (calorie_th = 4.184 J, BTU_IT, foot-pound force); SI Brochure 2019 (elementary charge 1.602176634e-19 C, so 1 eV exact).

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