Convert Femtojoules to Kilotons of TNT
Convert Femtojoules (fJ) to Kilotons of TNT (kt(TNT)) instantly and accurately.
Conversion Formula
kt(TNT) = fJ × 2.390057361e-28
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 Kilotons of TNT
A kiloton of TNT (kt(TNT)) = 10³ tons of TNT = exactly 4.184 TJ. It is the standard unit for sub-megaton nuclear weapon yields. Hiroshima's Little Boy: ~12-18 kt; Nagasaki's Fat Man: ~19-23 kt. The W88 warhead (Trident II) is ~475 kt; the W76 is ~100 kt. The Beirut port explosion (2020): estimated 0.5-1.1 kt. A magnitude 5.0 earthquake releases ~0.5-2 kt of seismic energy. A kiloton blast creates a fireball ~90-100 m radius and a lethal thermal radius of ~1-2 km. 1 kt(TNT) = 4.184 TJ = 1,162.8 MWh.
Quick Reference Table
| Femtojoules (fJ) | Kilotons of TNT (kt(TNT)) |
|---|---|
| 1 fJ | 2.39 × 10-28 kt(TNT) |
| 2 fJ | 4.78 × 10-28 kt(TNT) |
| 5 fJ | 1.195 × 10-27 kt(TNT) |
| 10 fJ | 2.39 × 10-27 kt(TNT) |
| 25 fJ | 5.975 × 10-27 kt(TNT) |
| 50 fJ | 1.195 × 10-26 kt(TNT) |
| 100 fJ | 2.39 × 10-26 kt(TNT) |