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Kilowatt-hours to Megajoules Converter

Enter the energy in kilowatt-hours below to convert it to megajoules.

Convert Kilowatt-hours to Megajoules

Enter a value in kilowatt-hours (kWh) to convert to megajoules (MJ).

Result
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18megajoules
5 kWh = 18 MJ
Result updates automatically
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Reference:NIST CODATA (CODATA Energy & Thermodynamic Constants)
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Kilowatt-hour to Megajoule Conversion Table

Table showing various kilowatt-hour measurements converted to megajoules. Click any preset value or arrow to load it into the converter.

Kilowatt-hours (kWh)Megajoules (MJ)
1 kWh3.6 MJ
2 kWh7.2 MJ
2.5 kWh9 MJ
5 kWh18 MJ
10 kWh36 MJ
15 kWh54 MJ
20 kWh72 MJ
25 kWh90 MJ
30 kWh108 MJ
50 kWh180 MJ

How to Convert Kilowatt-hours to Megajoules

To convert kilowatt-hours to megajoules, multiply the energy by the following conversion ratio: 3.6 megajoules/kilowatt-hour.

Since one kilowatt-hour is equal to 3.6 megajoules, you can use this simple formula to convert:

megajoules = kilowatt-hours × 3.6

The energy in megajoules is equal to the energy in kilowatt-hours multiplied by 3.6.

For example, here's how to convert 5 kilowatt-hours to megajoules using the formula above.

megajoules = (5 kWh × 3.6) = 18 MJ

How Many Megajoules Are in a Kilowatt-hour?

There are 3.6 megajoules in a kilowatt-hour, which is why we use this value in the formula above.

1 kWh = 3.6 MJ|1 MJ = 0.2777778 kWh

Our kilowatt-hour to megajoule calculator automatically converts your energy measurements with full decimal and scientific precision across US customary, imperial, and SI metric standards.

Kilowatt-hours and megajoules are both units used to measure energy. Keep reading to learn more about each unit.

What Is a Kilowatt-hour?

A kilowatt-hour is a unit of energy equal to 3,600,000 joules (J), the base unit for energy. Equal to 3.6 Megajoules (1,000 Wh). [1]

The kilowatt-hour is classified as a metric and SI-compatible unit of energy. Kilowatt-hours can be abbreviated as kWh; for example, 1 kilowatt-hour can be written as 1 kWh.

In the metric system, "kilo" is the standard SI prefix for thousands, or 10³. This makes the kilowatt-hour (kWh) a convenient decimal multiple of the joule (J).

In practice, kilowatt-hours (kWh) are widely used across large-scale industrial, bulk, and macro-level energy specifications within SI metric workflows, engineering documentation, and technical data sheets.

What Is a Megajoule?

A megajoule is a unit of energy equal to 1,000,000 joules (J), the base unit for energy. Equal to 1,000,000 Joules. [2]

The megajoule is classified as an International System of Units (SI) unit of energy. Megajoules can be abbreviated as MJ; for example, 1 megajoule can be written as 1 MJ.

In the metric system, "mega" is the standard SI prefix for millions, or 10⁶. This makes the megajoule (MJ) a convenient decimal multiple of the joule (J).

In practice, megajoules (MJ) are widely used across large-scale industrial, bulk, and macro-level energy specifications within International System of Units (SI) workflows, engineering documentation, and technical data sheets.

When converting energy between kilowatt-hours (kWh) and megajoules (MJ), keep full floating-point precision (1 kWh = 3.6 MJ; 1 MJ = 0.2777778 kWh) during intermediate calculations and round only the final megajoule figure to match your instrument tolerance.

More Kilowatt-hour & Megajoule Conversions

Need to calculate in the opposite direction? Use our megajoules to kilowatt-hours calculator to switch your starting unit immediately. You can also explore related tools such as converting megajoules to kilowatt-hours, converting kilowatt-hours to joules, or converting kilowatt-hours to btus.

Frequently Asked Questions

There are 3.6 megajoules (MJ) in 1 kilowatt-hour (kWh). Conversely, 1 megajoule (MJ) is equal to 0.27778 kilowatt-hours (kWh).

References

NIST · BIPM · ISO
  1. [1]
    NIST CODATA (CODATA Energy & Thermodynamic Constants)·Energy Metrology Standard — Kilowatt-hours (kWh) to Megajoules (MJ)
    NIST CODATA Standard
  2. [2]
    NIST SP 811 (NIST SP 811 App. B.9 (Energy, Work & Heat))·Unit Specifications: Kilowatt-hour (kWh) & Megajoule (MJ)
    NIST SP 811 Specification
  3. [3]
    BIPM (Derived SI Unit: Joule (J))·Conversion Factors & Mathematical Basis (kWh to MJ)
    BIPM Reference
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