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Convert between hours, minutes, seconds, days, weeks, and milliseconds with quick reference tables.
Time conversion is the process of translating a duration from one unit of measurement to another — such as hours to minutes, days to seconds, or weeks to milliseconds — using fixed mathematical relationships.
| Time Period | Hours | Minutes | Seconds |
|---|---|---|---|
| 1 minute | 0.0167 | 1 | 60 |
| 1 hour | 1 | 60 | 3,600 |
| 1 day | 24 | 1,440 | 86,400 |
| 1 week | 168 | 10,080 | 604,800 |
| 30 days | 720 | 43,200 | 2,592,000 |
| 1 year (365d) | 8,760 | 525,600 | 31,536,000 |
Multiply by 60 to convert hours to minutes.
min = h × 60
Multiply by 60 to convert minutes to seconds.
s = min × 60
Multiply by 24 to convert days to hours.
h = d × 24
Formula
1 day = 24 h = 1,440 min = 86,400 s = 86,400,000 mss (second) = SI base unit of time — defined as 9,192,631,770 cycles of Caesium-133 hyperfine transition
min = 60 seconds — derived from Babylonian sexagesimal (base-60) number system
h (hour) = 3,600 seconds or 60 minutes
ms = millisecond = 1/1,000 s — used in computing, networking, and sports timing
Worked Example
How many seconds are in 2.5 days?
Did you know? The second was historically defined as 1/86,400 of a mean solar day, but Earth's rotation is slightly irregular. Since 1967, it is defined by atomic resonance — making atomic clocks accurate to within 1 second in 300 million years.
Sources
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