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Joule to Kilojoule Converter

Free Energy Converter, Convert Joules, Calories, Kilowatt-Hours & BTU Instantly

1Joule=0.001Kilojoule
1 Kilojoule = 1000 Joule

Joule

Symbol
J
System
Metric/Imperial
Dimension
Various

Kilojoule

Symbol
kJ
System
Metric/Imperial
Dimension
Various

Quick Reference Table

JouleKilojouleKilojouleJoule
10.00111000
20.00222000
30.00333000
50.00555000
100.011010000
250.0252525000
500.055050000
1000.1100100000
5000.5500500000
1000110001000000

Conversion Formula

Kilojoule = Joule × 0.001

Joule = Kilojoule × 1000

Factors are from BIPM SI brochure and NIST SP 811, stored unrounded and computed via a base unit. Reverse factor is 1 ÷ 0.001.

How to convert Joule to Kilojoule

Multiply the value in joule by 0.001 to get kilojoule. For example, 5 Joule = 0.005 Kilojoule. All results in the energy converter update instantly as you type, so you can see every unit at once without manual math.

Common mistakes

Do not round the factor to 0.00 too early — keep full precision until the final display. For energy, always verify critical calculations (medicine, engineering) with a second source.

FAQ

How many Kilojoule in 1 Joule?
1 Joule = 0.001 Kilojoule.
How many Joule in 1 Kilojoule?
1 Kilojoule = 1000 Joule.
What is the source?
BIPM/NIST via OmniConverter base-unit engine. Source table and formula above are exact.

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joule to kilojoule Conversion | Compare Units