Hours to seconds
Multiply hours by 3,600 to get seconds.
3 h = 10,800 s
How to convert hours to seconds
The second is the SI base unit of time, defined by the caesium-133 hyperfine transition. The hour is exactly 60 minutes (3600 seconds).
Worked example — 3 h: 3 × 3,600 = 10,800 s.
Hours to seconds table
| Hours | Seconds |
|---|---|
| 0.25 h | 900 s |
| 0.5 h | 1,800 s |
| 1 h | 3,600 s |
| 2 h | 7,200 s |
| 3 h | 10,800 s |
| 5 h | 18,000 s |
| 8 h | 28,800 s |
| 12 h | 43,200 s |
| 24 h | 86,400 s |
Reverse and related
About hours and seconds
Hour (h)
1 h = 3,600 sDefinition. Exactly 60 minutes (3600 seconds)
History and origin
The hour divides the day into 24 parts, a scheme inherited from ancient Egypt, and equals exactly 60 minutes or 3600 seconds. Fixed-length hours replaced older seasonal hours as mechanical clocks spread.
Current use
Hours structure the working day, schedules and pay, and are read off every clock.
Source: BIPM SI Brochure (2019); the second is defined by the caesium-133 transition
Second (s)
1 s = 0.000277778 hDefinition. The SI base unit of time, defined by the caesium-133 hyperfine transition
History and origin
The second was historically one 86400th of a day, but since 1967 it has been defined by the caesium atom, as 9 192 631 770 oscillations of its radiation. This atomic definition made it far more precise than astronomical timekeeping.
Current use
The second is the SI base unit of time, underlying clocks, timers and all scientific measurement.
Source: BIPM SI Brochure (2019); the second is defined by the caesium-133 transition
Where people use this
Hours: schedules, work and pay. Seconds: timers, physics. 1 hour is exactly 3600 seconds.
Every value is carried to full double precision; the display is rounded.
Both units are defined in BIPM SI Brochure (2019); the second is defined by the caesium-133 transition.
Questions people ask
How many seconds in an hour?
One hour is exactly 3600 seconds.
How many seconds is 2 hours?
2 hours is 7200 seconds.
How many seconds is half an hour?
Half an hour is 1800 seconds.