Convert Hours to Seconds
Convert Hours (h) to Seconds (s) instantly and accurately.
Conversion Formula
s = h × 3600
About Hours
An hour (h) = exactly 3,600 s. The 24-hour day traces to ancient Egypt (10 daylight hours + 2 twilight + 12 night star-rise periods). Time zones are integer or half-hour UTC offsets (exceptions: India +5:30, Nepal +5:45). The kilowatt-hour = 3,600,000 J; Tc-99m half-life = 6.0067 h. Drug dosing and pharmacokinetics are expressed in hours. 1 h = 3,600 s = 60 min = 1/24 day.
About Seconds
The second (s) is the SI base unit of time, defined since 1967 as exactly 9,192,631,770 periods of the caesium-133 ground-state hyperfine transition at 0 K. Caesium fountain clocks realise this to ~10⁻¹⁶ (1 s lost per ~300 million years); optical lattice clocks (Sr, Yb) reach ~10⁻¹⁸. The second links to the metre via the defined speed of light c = 299,792,458 m/s exactly. 1 s = 1,000 ms = 1/60 min.
Quick Reference Table
| Hours (h) | Seconds (s) |
|---|---|
| 1 h | 3600 s |
| 2 h | 7200 s |
| 5 h | 18000 s |
| 10 h | 36000 s |
| 25 h | 90000 s |
| 50 h | 180000 s |
| 100 h | 360000 s |