Kilojoules to Watt-hours Converter
Enter the energy in kilojoules below to convert it to watt-hours.
Convert Kilojoules to Watt-hours
Enter a value in kilojoules (kJ) to convert to watt-hours (Wh).
Kilojoule to Watt-hour Conversion Table
Table showing various kilojoule measurements converted to watt-hours. Click any preset value or arrow to load it into the converter.
| Kilojoules (kJ) | Watt-hours (Wh) |
|---|---|
| 1 kJ | 0.2777778 Wh |
| 2 kJ | 0.5555556 Wh |
| 2.5 kJ | 0.6944444 Wh |
| 5 kJ | 1.3888889 Wh |
| 10 kJ | 2.7777778 Wh |
| 15 kJ | 4.1666667 Wh |
| 20 kJ | 5.5555556 Wh |
| 25 kJ | 6.9444444 Wh |
| 30 kJ | 8.3333333 Wh |
| 50 kJ | 13.8888889 Wh |
How to Convert Kilojoules to Watt-hours
To convert kilojoules to watt-hours, multiply the energy by the following conversion ratio: 0.2777778 watt-hours/kilojoule.
Since one kilojoule is equal to 0.2777778 watt-hours, you can use this simple formula to convert:
The energy in watt-hours is equal to the energy in kilojoules multiplied by 0.2777778.
For example, here's how to convert 5 kilojoules to watt-hours using the formula above.
How Many Watt-hours Are in a Kilojoule?
There are 0.2777778 watt-hours in a kilojoule, which is why we use this value in the formula above.
Our kilojoule to watt-hour calculator automatically converts your energy measurements with full decimal and scientific precision across US customary, imperial, and SI metric standards.
Kilojoules and watt-hours are both units used to measure energy. Keep reading to learn more about each unit.
What Is a Kilojoule?
A kilojoule is a unit of energy equal to 1,000 joules (J), the base unit for energy. Equal to 1,000 Joules. [1]
The kilojoule is classified as a metric and SI-compatible unit of energy. Kilojoules can be abbreviated as kJ; for example, 1 kilojoule can be written as 1 kJ.
In the metric system, "kilo" is the standard SI prefix for thousands, or 10³. This makes the kilojoule (kJ) a convenient decimal multiple of the joule (J).
In practice, kilojoules (kJ) 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 Watt-hour?
A watt-hour is a unit of energy equal to 3,600 joules (J), the base unit for energy. Equal to 3,600 Joules. [2]
The watt-hour is classified as a metric and SI-compatible unit of energy. Watt-hours can be abbreviated as Wh; for example, 1 watt-hour can be written as 1 Wh.
When working with watt-hours (Wh) in formulas or technical specifications, always verify whether your target system uses SI metric, US customary, or British imperial standards.
In practice, watt-hours (Wh) are widely used across large-scale industrial, bulk, and macro-level energy specifications within SI metric workflows, engineering documentation, and technical data sheets.
When converting energy between kilojoules (kJ) and watt-hours (Wh), keep full floating-point precision (1 kJ = 0.2777778 Wh; 1 Wh = 3.6 kJ) during intermediate calculations and round only the final watt-hour figure to match your instrument tolerance.
More Kilojoule & Watt-hour Conversions
Need to calculate in the opposite direction? Use our watt-hours to kilojoules calculator to switch your starting unit immediately. You can also explore related tools such as converting watt-hours to kilojoules, converting ampere-hours to watt-hours, or converting milliampere-hours to watt-hours.
Convert from Kilojoules
Frequently Asked Questions
References
- [1]NIST CODATA StandardNIST CODATA (CODATA Energy & Thermodynamic Constants)·Energy Metrology Standard — Kilojoules (kJ) to Watt-hours (Wh)
- [2]NIST SP 811 SpecificationNIST SP 811 (NIST SP 811 App. B.9 (Energy, Work & Heat))·Unit Specifications: Kilojoule (kJ) & Watt-hour (Wh)
- [3]BIPM ReferenceBIPM (Derived SI Unit: Joule (J))·Conversion Factors & Mathematical Basis (kJ to Wh)