UnitFlip
Saved
Energy

Convert joules to kj

1 joule equals 0.001 kilojoules. Enter a value below to convert instantly.

1 J
0.001 kJ

Multiply the number of joules by 0.001 to get kilojoules. How this is calculated

Copy link puts your number after the #, which browsers never send to a server — but the link itself carries it, so anyone you send it to sees the value. Save keeps the unit pair in this browser only; clear it any time from your saved list.

Need the other direction? Convert kilojoule to joule →

Formula

Multiply the number of joules by 0.001 to get kilojoules.

Step by step

  1. Start with 1 J.
  2. Multiply by the conversion factor 0.001.
  3. 1 × 0.001 = 0.001 kJ.

Joules to Kilojoules conversion table

Joules (J) Kilojoules (kJ)
1 0.001
2 0.002
5 0.005
10 0.01
20 0.02
50 0.05
100 0.1
500 0.5
1,000 1

Convert Joule to other energy units

1 J expressed in every other energy unit on this site.

  • Kilojoule kJ 0.001
  • Megajoule MJ 0.000001
  • Gigajoule GJ 1e-9
  • Millijoule mJ 1,000
  • Microjoule µJ 1,000,000
  • Nanojoule nJ 1,000,000,000
  • Attojoule aJ 1e+18
  • Erg erg 10,000,000
  • Calorie (thermochemical) cal 0.23900574
  • Kilocalorie kcal 0.00023900574
  • Calorie (IT) cal(IT) 0.2388459
  • Kilocalorie (IT) kcal(IT) 0.0002388459
  • Megacalorie Mcal 2.3900574e-7
  • Watt-hour Wh 0.00027777778
  • Kilowatt-hour kWh 2.7777778e-7
  • Megawatt-hour MWh 2.7777778e-10
  • Gigawatt-hour GWh 2.7777778e-13
  • Watt-second W·s 1
  • Kilowatt-second kW·s 0.001
  • Horsepower-hour hp·h 3.7250614e-7
  • British Thermal Unit BTU 0.00094781712
  • BTU (thermochemical) BTU(th) 0.00094845141
  • MBTU (thousand BTU) MBTU 9.4781712e-7
  • MMBTU (million BTU) MMBTU 9.4781712e-10
  • Therm (US) thm (US) 9.4804343e-9
  • Therm (EC) thm (EC) 9.4781339e-9
  • Ton-hour (refrigeration) ton·h 7.8984761e-8
  • Foot-pound ft·lbf 0.73756215
  • Inch-pound in·lbf 8.8507458
  • Foot-poundal ft·pdl 23.73036
  • Kilogram-force Meter kgf·m 0.10197162
  • Gram-force Centimeter gf·cm 10,197.162
  • Gram-force Meter gf·m 101.97162
  • Kilogram-force Centimeter kgf·cm 10.197162
  • Ounce-force Inch ozf·in 141.61193
  • Horsepower-hour (metric) PS·h 3.7767267e-7
  • Electronvolt eV 6.2415091e+18
  • Kiloelectronvolt keV 6.2415091e+15
  • Megaelectronvolt MeV 6,241,509,100,000
  • Gigaelectronvolt GeV 6,241,509,100
  • Hartree Eh 2.2937123e+17
  • Rydberg Ry 4.5874246e+17
  • Ton of TNT tTNT 2.3900574e-10
  • Kiloton of TNT ktTNT 2.3900574e-13
  • Megaton of TNT MtTNT 2.3900574e-16
  • Tonne of Oil Equivalent toe 2.388459e-11
  • Barrel of Oil Equivalent bboe 1.6345576e-10
  • Gigaton of TNT GtTNT 2.3900574e-19
  • Fuel Oil Equivalent (kiloliter) FOE (kL) 2.487709e-11
  • Fuel Oil Equivalent (US barrel) FOE (bbl) 1.5666399e-10

About the joule

The joule (J) is a SI unit of energy.

About the kilojoule

The kilojoule (kJ) is a SI unit of energy.

Where this conversion is used

Converting joules to kilojoules comes up when nutrition labels, electricity bills, heating, and physics.

Related conversions

Frequently asked questions

How many kilojoules are in a joule?

One joule equals 0.001 kilojoules.

How do you convert joules to kilojoules?

Multiply the number of joules by 0.001 to get kilojoules.

What is 1 kilojoule in joules?

One kilojoule equals 1,000 joules.

When would I convert joules to kilojoules?

This conversion is common when nutrition labels, electricity bills, heating, and physics.

Conversion factors are based on internationally agreed unit definitions. See our methodology and sources for details on how these values are verified.