Convert Watt-Hours to Femtojoules
Convert Watt-Hours (Wh) to Femtojoules (fJ) instantly and accurately.
Conversion Formula
fJ = Wh × 3.600000000e+18
About Watt-Hours
A watt-hour (Wh) is the energy delivered by 1 watt for one hour - exactly 3,600 J. It is the practical unit for small-scale electrical energy: a 10,000 mAh 5 V power bank stores 50 Wh; a laptop battery holds 50-90 Wh; a smartphone battery holds 10-15 Wh; an AA alkaline cell stores ~3 Wh. LED lamps labelled 9 W save 51 Wh/h over a 60 W incandescent. IATA dangerous-goods rules use Wh as the threshold for lithium batteries in aircraft: cells >20 Wh and batteries >100 Wh need special approval. 1 Wh = 3,600 J = 3.412 BTU.
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.
Quick Reference Table
| Watt-Hours (Wh) | Femtojoules (fJ) |
|---|---|
| 1 Wh | 3.6 × 1018 fJ |
| 2 Wh | 7.2 × 1018 fJ |
| 5 Wh | 1.8 × 1019 fJ |
| 10 Wh | 3.6 × 1019 fJ |
| 25 Wh | 9 × 1019 fJ |
| 50 Wh | 1.8 × 1020 fJ |
| 100 Wh | 3.6 × 1020 fJ |