Convert Watt-Hours to Attojoules
Convert Watt-Hours (Wh) to Attojoules (aJ) instantly and accurately.
Conversion Formula
aJ = Wh × 3.600000000e+21
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 Attojoules
An attojoule (aJ) is 10⁻¹⁸ J - the scale of individual X-ray photons and superconducting qubit circuits. A 1 keV X-ray photon carries 160 aJ; a visible green photon (~550 nm) carries ~0.36 aJ. Josephson junction energies in superconducting qubits are set in tens to hundreds of aJ to achieve quantum coherence at millikelvin temperatures. XRISM's cryogenic TES X-ray spectrometer resolves individual photon energies at the hundreds-of-aJ level with ~7 eV FWHM resolution. 1 aJ = 10⁻¹⁸ J = 6.242 eV.
Quick Reference Table
| Watt-Hours (Wh) | Attojoules (aJ) |
|---|---|
| 1 Wh | 3.6 × 1021 aJ |
| 2 Wh | 7.2 × 1021 aJ |
| 5 Wh | 1.8 × 1022 aJ |
| 10 Wh | 3.6 × 1022 aJ |
| 25 Wh | 9 × 1022 aJ |
| 50 Wh | 1.8 × 1023 aJ |
| 100 Wh | 3.6 × 1023 aJ |