How do I convert joules to kilojoules?

Multiply the joule value by 0.001. So x J × 0.001 = the equivalent in kJ.

What is 5 joules in kilojoules?

5 joules equals 0.005 kilojoules.

What is 10 joules in kilojoules?

10 joules equals 0.01 kilojoules.

What is 100 joules in kilojoules?

100 joules equals 0.1 kilojoules.

How do I convert back from kilojoules to joules?

Multiply the kilojoule value by 1000. For example, 1 kJ = 1000 J.

Is the joule bigger than the kilojoule?

No. 1 joule is smaller than 1 kilojoule. It takes 1000 joules to equal 1 kilojoule.

Are these conversion factors exact?

Yes. The factor of 0.001 is derived directly from the SI definitions of joule and kilojoule.

Joules to Kilojoules Converter

1 J = 0.001 kJ

1 joule equals 0.001 kilojoules. To convert joules to kilojoules, multiply the joule value by 0.001. For quick reference: 1 J = 0.001 kJ, 5 J = 0.005 kJ, 10 J = 0.01 kJ, 100 J = 0.1 kJ.

From

0.001

FormulaKilojoules = Joules × 0.001

Quick

How to convert joules to kilojoules

Take your value
Start with your value in joules.
Multiply by 0.001
Multiply the joule value by 0.001. This is the exact conversion factor from joules to kilojoules.
Read the result
The product is your value in kilojoules. For example, 5 J × 0.001 = 0.005 kJ.

Conversion formula

The exact factor from joules to kilojoules is 0.001.

Kilojoules = Joules × 0.001

Joules to Kilojoules conversion table

Fifty common reference values, hand-picked for skim utility. Use the calculator above for any value not listed.

Conversion table from joules to kilojoules
Joules (J)	Kilojoules (kJ)
0.001 J	1.0000 × 10^−6 kJ
0.01 J	1.0000 × 10^−5 kJ
0.1 J	0.0001 kJ
0.5 J	0.0005 kJ
1 J	0.001 kJ
1.5 J	0.0015 kJ
2 J	0.002 kJ
5 J	0.005 kJ
10 J	0.01 kJ
20 J	0.02 kJ
50 J	0.05 kJ
100 J	0.1 kJ
200 J	0.2 kJ
250 J	0.25 kJ
500 J	0.5 kJ
1000 J	1 kJ
2000 J	2 kJ
2500 J	2.5 kJ
3600 J	3.6 kJ
5000 J	5 kJ
7500 J	7.5 kJ
10000 J	10 kJ
25000 J	25 kJ
50000 J	50 kJ
100000 J	100 kJ
250000 J	250 kJ
500000 J	500 kJ
1000000 J	1000 kJ
2000000 J	2000 kJ
3600000 J	3600 kJ
5000000 J	5000 kJ
10000000 J	10000 kJ
25000000 J	25000 kJ
50000000 J	50000 kJ
100000000 J	100000 kJ
250000000 J	250000 kJ
500000000 J	500000 kJ
1000000000 J	1000000 kJ
2000000000 J	2000000 kJ
5000000000 J	5000000 kJ
10000000000 J	10000000 kJ
20000000000 J	20000000 kJ
50000000000 J	50000000 kJ
100000000000 J	100000000 kJ
1000000000000 J	1000000000 kJ
10000000000000 J	10000000000 kJ
100000000000000 J	100000000000 kJ
1000000000000000 J	1000000000000 kJ
10000000000000000 J	10000000000000 kJ
100000000000000000 J	100000000000000 kJ

Real-world reference

A heartbeat releases about 1 J of mechanical work. Lifting an apple 1 m takes roughly 1 J.

Frequently asked questions

How many kilojoules are in 1 joule?: 1 joule equals 0.001 kilojoules.
How do I convert joules to kilojoules?: Multiply the joule value by 0.001. So x J × 0.001 = the equivalent in kJ.
What is 5 joules in kilojoules?: 5 joules equals 0.005 kilojoules.
What is 10 joules in kilojoules?: 10 joules equals 0.01 kilojoules.
What is 100 joules in kilojoules?: 100 joules equals 0.1 kilojoules.
How do I convert back from kilojoules to joules?: Multiply the kilojoule value by 1000. For example, 1 kJ = 1000 J.
Is the joule bigger than the kilojoule?: No. 1 joule is smaller than 1 kilojoule. It takes 1000 joules to equal 1 kilojoule.
Are these conversion factors exact?: Yes. The factor of 0.001 is derived directly from the SI definitions of joule and kilojoule.

About the joule and the kilojoule

The joule

The joule (J) is the SI derived unit of energy, work, and heat — defined as the energy transferred when a force of one newton acts over one meter. The joule is the standard unit in physics, chemistry, and most modern engineering documentation.

The kilojoule

The kilojoule (kJ) equals exactly 1,000 joules. It is the standard unit on EU and many non-US nutrition labels — 1 dietary calorie ≈ 4.184 kJ. It also appears in industrial-process specifications and energy-storage ratings.

Joules to Kilocalories

J → kcal

Joules to Watt-hours

J → Wh

Joules to Kilowatt-hours

J → kWh

Kilojoules to Calories

kJ → cal