Convert hours to seconds
Convert hours to seconds instantly. 1 h = 3,600 s. Formula, worked examples and a quick reference table.
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One hour equals 3,600 seconds. To convert any number of hours to seconds, multiply by 3,600.
The converter above works in both directions and updates as you type. Below you will find the formula, a worked example and a reference table of common values.
Time conversions are exact down to the day and approximate above it. Seconds, minutes, hours and days have fixed ratios, but a month has no fixed length and a year has two — 365 days in the calendar and 365.25 in the astronomical convention used here. For anything with legal or contractual weight, count the actual calendar dates rather than converting a duration, because the difference accumulates precisely where it is least welcome.
hours to seconds formula
To go the other way, use hour = second ÷ 3,600.
About these units
The hour is 3,600 seconds. Its length is arbitrary in physical terms: it descends from dividing daylight into twelve parts, which meant the hour changed with the seasons until mechanical clocks fixed it.
The second is defined by the caesium atom: 9,192,631,770 oscillations of a particular transition. Every other time unit is now derived from it.
Hour is also written hours, hr and hrs. Second is also written seconds, sec and secs.
Sources
hours to seconds conversion table
| Hour | Second |
|---|---|
| 1 h | 3,600 s |
| 2 h | 7,200 s |
| 3 h | 10,800 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 |
Frequently asked questions
How many seconds are in a hour? +
There are 3,600 seconds in one hour.
What is 10 h in s? +
10 h equals 36,000 s. Multiply 10 by 3,600.
How do I convert second back to hour? +
Use hour = second ÷ 3,600. The converter above handles both directions, or see our dedicated seconds to hours page.
How accurate is this hour to second conversion? +
The factor used is 3,600, carried at full double precision. Where a unit has an exact legal definition the factor is exact rather than approximate. Rounding is applied only to the displayed result, so the answer is never a calculation done on an already-rounded number.
Is there a quick way to estimate h to s in my head? +
The factor is exactly 3,600, which is short enough to apply directly without an approximation.