Convert Femtojoules to Kilojoules
Convert Femtojoules (fJ) to Kilojoules (kJ) instantly and accurately.
Conversion Formula
kJ = fJ × 1.000000000e-18
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 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
| Femtojoules (fJ) | Kilojoules (kJ) |
|---|---|
| 1 fJ | 1 × 10-18 kJ |
| 2 fJ | 2 × 10-18 kJ |
| 5 fJ | 5 × 10-18 kJ |
| 10 fJ | 1 × 10-17 kJ |
| 25 fJ | 2.5 × 10-17 kJ |
| 50 fJ | 5 × 10-17 kJ |
| 100 fJ | 1 × 10-16 kJ |