Convert Millijoules to Megajoules
Convert Millijoules (mJ) to Megajoules (MJ) instantly and accurately.
Conversion Formula
MJ = mJ × 1.000000000e-9
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 Megajoules
A megajoule (MJ) is 10⁶ J - the scale of fuel combustion in vehicles and kinetic energy of road traffic. Energy content: 1 L diesel ~34.9 MJ; 1 L petrol ~32.2 MJ. A 1,500 kg car at 100 km/h has KE = ½ × 1,500 × 27.78² ≈ 0.579 MJ; at 200 km/h it carries 2.31 MJ - explaining crash severity's quadratic speed dependence. A 60 kWh EV battery stores 60 × 3.6 = 216 MJ. Detonation of 1 kg TNT releases 4.184 MJ. Adults at rest metabolise ~6-9 MJ/day. 1 MJ = 10⁶ J = 239.0 kcal = 0.27778 kWh = 947.8 BTU.
Quick Reference Table
| Millijoules (mJ) | Megajoules (MJ) |
|---|---|
| 1 mJ | 1 × 10-9 MJ |
| 2 mJ | 2 × 10-9 MJ |
| 5 mJ | 5 × 10-9 MJ |
| 10 mJ | 1 × 10-8 MJ |
| 25 mJ | 2.5 × 10-8 MJ |
| 50 mJ | 5 × 10-8 MJ |
| 100 mJ | 1 × 10-7 MJ |