Convert Millijoules to Kilojoules
Convert Millijoules (mJ) to Kilojoules (kJ) instantly and accurately.
Conversion Formula
kJ = mJ × 1.000000000e-6
About Millijoules
A millijoule (mJ) is 10⁻³ J - the scale of surgical lasers, spark ignition, and the kinetic energy of small everyday objects. Nd:YAG lasers for ophthalmology and tattoo removal deliver 10-200 mJ per pulse. The minimum spark energy to ignite methane-air is ~0.29 mJ; an automotive spark plug discharges 30-60 mJ per cycle. A 2 g mosquito flying at 1 m/s has kinetic energy ½ × 0.002 × 1² = 1 mJ. Electrocautery monopolar pulses deliver 50-500 mJ to coagulate blood vessels. 1 mJ = 10⁻³ J = 0.2390 cal.
About Kilojoules
A kilojoule (kJ) is exactly 1,000 J and is the standard energy unit for food and physical chemistry. EU, Australian, and NZ food labels are mandatory in kJ: recommended adult intake is ~8,400 kJ/day. Bond dissociation energies: C-H bond 413 kJ/mol; C=C double bond 614 kJ/mol; N≡N triple bond 945 kJ/mol. Specific heat of water: 4.184 kJ/(kg·K). A cyclist riding at 150 W for one hour expends 540 kJ. Charpy and Izod impact toughness tests record results in J and kJ. 1 kJ = 1,000 J = 239.0 cal = 0.94782 BTU = 0.27778 Wh.
Quick Reference Table
| Millijoules (mJ) | Kilojoules (kJ) |
|---|---|
| 1 mJ | 1 × 10-6 kJ |
| 2 mJ | 2 × 10-6 kJ |
| 5 mJ | 5 × 10-6 kJ |
| 10 mJ | 1 × 10-5 kJ |
| 25 mJ | 2.5 × 10-5 kJ |
| 50 mJ | 5 × 10-5 kJ |
| 100 mJ | 1 × 10-4 kJ |