Kilojoule (kJ)
Exactly 1000 joules.
What is a kilojoule?
- Symbol
- kJ
- Quantity
- Energy
- Unit system
- SI
- Definition
- Exactly 1000 joules.
- Exact
- Yes, the value is exact by definition
- Source
- SI Brochure, 9th edition (BIPM, 2019)
Common applications
Used for food energy on nutrition labels in many countries, often next to kilocalories.
Kilojoule in other energy units
- 1 kJ = 1000 JJoule
- 1 kJ = 0.001 MJMegajoule
- 1 kJ ≈ 0.2777777778 WhWatt-hour
- 1 kJ ≈ 0.0002777777778 kWhKilowatt-hour
- 1 kJ ≈ 239.0057361 calCalorie (thermochemical)
- 1 kJ ≈ 0.2390057361 kcalKilojoule to Kilocalorie (thermochemical) converter
- 1 kJ ≈ 0.9478171203 BTUKilojoule to British thermal unit (IT) converter
- 1 kJ ≈ 737.5621493 ft·lbfFoot-pound-force
- 1 kJ ≈ 6.241509074e+21 eVElectronvolt
- 1 kJ = 10000000000 ergErg
Kilojoule quick reference
| Kilojoule | Kilocalorie (thermochemical) | British thermal unit (IT) | Joule |
|---|---|---|---|
| 1 kJ | ≈ 0.2390057361 kcal | ≈ 0.9478171203 BTU | = 1000 J |
| 10 kJ | ≈ 2.390057361 kcal | ≈ 9.478171203 BTU | = 10000 J |
| 100 kJ | ≈ 23.90057361 kcal | ≈ 94.78171203 BTU | = 100000 J |
| 1000 kJ | ≈ 239.0057361 kcal | ≈ 947.8171203 BTU | = 1000000 J |
Where the kilojoule fits
The next smaller energy unit is the calorie (cal). 1 kJ ≈ 239.0057361 cal, and 1 cal = 0.004184 kJ.
The next larger energy unit is the British thermal unit (BTU). 1 kJ ≈ 0.9478171203 BTU, and 1 BTU = 1.05505585262 kJ.
Frequently asked questions
- How many kilocalories are in one kilojoule?
- One kilojoule ≈ 0.2390057361 kcal (kilocalories).
- How many British thermal units are in one kilojoule?
- One kilojoule ≈ 0.9478171203 BTU (British thermal units).
- How many joules are in one kilojoule?
- One kilojoule = 1000 J (joules).