Time Converter
Convert any time duration between milliseconds, seconds, minutes, hours, days, weeks, months, and years.
Enter a value above to see the conversion.
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How Time Conversion Works
All time units are expressed as a fixed ratio to seconds — the SI base unit of time. To convert from unit A to unit B, the value is multiplied by the second factor of A, then divided by the second factor of B.
result = value × (A_to_s / B_to_s)
Example: 2 hr → min = 2 × (3600 / 60) = 120 min
Reference Values
- 1 min = 60 s
- 1 hr = 3,600 s
- 1 day = 86,400 s
- 1 wk = 604,800 s
- 1 mo ≈ 2,629,746 s (365.25/12 d)
- 1 yr = 31,557,600 s (365.25 d)
Exact vs Average Time Units
Milliseconds through weeks are exact and universally consistent. A second is defined by the SI as the duration of 9,192,631,770 periods of radiation of the caesium-133 atom. Minutes, hours, and days all derive directly from this.
Months and years are inherently approximate because calendar months range from 28 to 31 days, and years are 365 or 366 days. This converter uses the Gregorian average — 365.25 days per year, and 365.25 ÷ 12 ≈ 30.4375 days per month — which is accurate for general duration calculations but may differ from specific calendar dates.