How to Convert Hours to Seconds (h to s)
Time conversions help with project planning, payroll hours and working out how long a loan or COE period really is. This guide shows how to convert hours into seconds by hand, with examples and a quick-reference table.
The conversion
To convert hours to seconds, multiply the value by 3,600. To go the other way, divide by the same number (or multiply by 0.0002777778). For a quick estimate, multiply by about 3,600.
Seconds = hours × 3,600
Worked examples
- 3 h = 10,800 s
- 12.5 h = 45,000 s
- 75 h = 270,000 s
Hours to Seconds table
| Hours | Seconds |
|---|---|
| 1 h | 3,600 s |
| 2 h | 7,200 s |
| 5 h | 18,000 s |
| 10 h | 36,000 s |
| 20 h | 72,000 s |
| 25 h | 90,000 s |
| 50 h | 180,000 s |
| 100 h | 360,000 s |
| 250 h | 900,000 s |
| 500 h | 1,800,000 s |
| 1,000 h | 3,600,000 s |
Common questions
Is h to s exact?
The factors used here are the internationally defined values where they exist; results are rounded for display only.
How do I convert back?
Use the Seconds to Hours converter.
Mistakes to avoid
Rounding the factor too early
Using 3 instead of 3.28 for feet per metre introduces an error of almost 9% before you have started.
Multiplying when you should divide
Converting to a smaller unit gives a bigger number, and converting to a larger unit gives a smaller one. If your answer moves the wrong way, you have inverted the factor.
Dropping the units
A bare number without a unit is easy to misread later. Always write the unit with the result.
Background
For everyday use, three or four significant figures are usually enough. Engineering, science and trade documents may need more, and rounding should happen only at the end of a calculation.
Unit conversion is simply multiplication by a fixed ratio. The ratio between two units of the same quantity never changes, so once you know it you can convert any value in either direction.
Writing the units next to every number while you work is the simplest way to avoid mistakes. If the units do not cancel to leave the one you want, the calculation is set up wrongly.
For any value, use the Hours to Seconds Converter or browse all time converters.
Run your own numbers: Hours to Seconds Converter