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Convert between seconds, minutes, hours, days and more.
⏱️ Months and years use averages (30.44 days/month, 365.25 days/year).
This tool converts between time units — from milliseconds to years. It uses precise factors for small units (seconds, minutes, hours, days) and averages for months and years, since those vary in length.
Months vary from 28 to 31 days, so there's no exact conversion. This tool uses the average of 30.44 days per month (365.25 ÷ 12). For precise date math, use the Date Difference Calculator instead.
The Time Converter converts time converterfrom one unit to another using the exact internationally defined conversion factors. Type a value, choose your source and target units, and the converted result is shown instantly — no waiting, no page reload.
Manual conversion is error-prone because it means memorizing ratios (how many feet in a meter, how many pints in a liter). This tool removes that friction: the conversion factor is built in, and the math is done to full precision with no rounding until the final displayed number.
Common uses: people reach for this tool when they need to look up a hours to minutes converter, seconds to hours converter, days to weeks calculator, or milliseconds to seconds.
Browser-based tools like this one have a few real advantages over installed software or manual methods:
The Time Converter is based on the following formula:
1 min = 60 s 1 h = 60 min = 3600 s 1 d = 24 h = 86,400 s 1 week = 604,800 s 1 month (average) = 30.436875 d 1 year = 365.2425 d = 31,556,952 s
Variables: s = seconds min = minutes h = hours d = days week = weeks (7 days) month = average calendar month year = average Gregorian year
Seconds, minutes, hours and days are defined exactly: a day is 86,400 s. Calendar years average 365.2425 days under the Gregorian leap rule, which makes the average month 30.436875 days. Astronomy uses the Julian year of exactly 365.25 days = 31,557,600 s.
Worked example: How long is 1,000,000 seconds? days = 1,000,000 ÷ 86,400 ≈ 11.57 days Convert 2.5 h the other way: min = 2.5 × 60 = 150 min s = 150 × 60 = 9000 s
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