Energy Conversion Calculator

Easily handle converting energy units, joules, microjoules, kilojoules, etc, with our precise energy conversion calculator. Get fast, accurate results

Clear
Result1,000 mJ1 J converted
1 J equals1,000 mJ
1 mJ equals0.001 J

Joule to millijoule reference

joulemillijoule
1 J1,000 mJ
2 J2,000 mJ
5 J5,000 mJ
10 J10,000 mJ
25 J25,000 mJ
50 J50,000 mJ
100 J100,000 mJ
500 J500,000 mJ
1,000 J1,000,000 mJ

How to convert joule to millijoule

One joule equals 1000 mJ, so multiply the number of joules by 1000:

mJ = J × 1000

Going the other way

One millijoule equals 0.001 J, so to convert back:

J = mJ × 0.001

Both directions are shown in the results above, and the drop-downs let you convert between any pair of energy units — not just these two.