Hours to Seconds
Type a value in either box to convert between hours and seconds. The factor is 3600.
| Hours | Seconds |
|---|---|
| 1 hr | 3600 s |
| 2 hr | 7200 s |
| 3 hr | 10800 s |
| 5 hr | 18000 s |
| 10 hr | 36000 s |
| 25 hr | 90000 s |
| 50 hr | 180000 s |
| 100 hr | 360000 s |
How to use
- Enter a value in the Hours field.
- The Seconds figure appears immediately — no button to press.
- Typing in the Seconds field converts back to Hours the same way.
- Use the reference table for the values that come up most often.
Hours to Seconds formula
The factor from hours to seconds is 3600.
s = hr × 3600
Put another way, one hour is exactly 3,600 seconds.
Why this factor: the hour and the second are both defined against the second, so dividing one definition by the other gives 3600 directly. Both definitions are set out in full below.
To go the other way, divide by 3600 — or use the Seconds to Hours converter, which is the same calculation reversed.
Worked example
Given 15 hr, multiplying by 3600 yields 54000 s.
15 hr × 3600 = 54000 s
The converter above does this for any value you type, in either direction.
What is an hour?
An hour is sixty minutes — the primary unit of the working day.
Definition: Exactly 3,600 seconds.
Where it is used: Work and billing time, flight durations, and energy quantities such as the kilowatt-hour.
What is a second?
The second is the SI base unit of time and the most precisely realized unit in all of measurement.
Definition: Defined by fixing the caesium-133 hyperfine transition frequency at exactly 9,192,631,770 hertz — the basis of every atomic clock.
Where it is used: Universal, and the reference for all other time units.
Hours vs Seconds
The hour is a specialized unit while the second is an SI unit. That is why the factor between them is not a round number: the two systems were defined independently and only later tied together by exact agreement.
Frequently asked questions
How many seconds are in an hour?
One hour equals 3600 seconds.
What is the formula to convert hours to seconds?
Multiply the number of hours by 3600. To reverse it, divide by 3600 instead.
How do I convert seconds back to hours?
Divide by 3600, which is the same as multiplying by 0.000277777778.
How many seconds are in 10 hours?
10 hr works out to 36000 s.
How is the hour defined?
Exactly 3,600 seconds.