EngiRef / Energy conversion

Convert Kilojoules to Joules (kJ to J)

1 kJ = 1000 J. Convert kilojoules to joules with the exact factor, a common-values table and a free converter.

EnergySingle factor7 worked values

Conversion factor

J = kJ × 1000

1 kJ = 1000 J

Multiply by 1000 J to go from kilojoules to joules, or divide by it to come back. The factor and every value below are computed by the same converter that runs at /convert, so this page and the tool cannot disagree.

kJ to J table

Common kilojoules values converted to joules
Kilojoules (kJ)Joules (J)
1 kJ1000 J
2 kJ2000 J
5 kJ5000 J
10 kJ10000 J
20 kJ20000 J
50 kJ50000 J
100 kJ100000 J

Every figure is computed at build time by the site’s own converter from the energy unit registry. For a value that is not listed, put it into the interactive converter.

Frequently asked questions

How many joules are in one kilojoule?

One kilojoule is 1000 J, so 100 kJ is 100000 J.

What is the formula to convert kilojoules to joules?

J = kJ × 1000. Multiply the value in kilojoules by 1000 to get joules.

How do I convert joules back to kilojoules?

kJ = J × 0.001, so 1 J is 0.001 kJ. The J to kJ page carries the same table in that direction.