Convert Femtojoules to Millijoules

Convert Femtojoules (fJ) to Millijoules (mJ) instantly and accurately.

Femtojoules (fJ)
Millijoules (mJ)

Conversion Formula

mJ = fJ × 1.000000000e-12

About Femtojoules

A femtojoule (fJ) is 10⁻¹⁵ J - the scale of gamma-ray photons, molecular motor work, and state-of-the-art digital logic. The electron rest-mass energy is 81.87 fJ; a 100 keV X-ray photon carries 16.02 fJ. A single myosin II motor protein power stroke dissipates ~5-40 fJ. ATP hydrolysis under cellular conditions yields ~80-100 fJ of free energy. Advanced 3 nm CMOS gates switch at ~0.1-1 fJ per operation. Ultrafast fiber laser oscillators produce pulses of 0.1-10 fJ before amplification. 1 fJ = 10⁻¹⁵ J = 6.242 keV.

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.

Quick Reference Table

Femtojoules (fJ)Millijoules (mJ)
1 fJ1 × 10-12 mJ
2 fJ2 × 10-12 mJ
5 fJ5 × 10-12 mJ
10 fJ1 × 10-11 mJ
25 fJ2.5 × 10-11 mJ
50 fJ5 × 10-11 mJ
100 fJ1 × 10-10 mJ

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