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Convert seconds, minutes, hours, days, and weeks in one click.
Convert time spans between seconds, minutes, hours, days, and weeks. Useful for project planning, workout timing, travel itineraries, and answering “how many hours is that, exactly?”
Time conversion is simple at small scales and slippery at large ones. Seconds, minutes, hours, days, and weeks convert with exact factors everyone knows: 60 seconds per minute, 60 minutes per hour, 24 hours per day, 7 days per week. Below the second, milliseconds (10^-3), microseconds (10^-6), and nanoseconds (10^-9) serve computing and science. The slipperiness starts at months and years: a month is 28 to 31 days, so converters use the average month of 30.436875 days (365.25/12), and a year is 365 days — or 365.25 accounting for leap years, the figure astronomers and long-range planners use.
The common conversions: 1 hour = 3,600 seconds; 1 day = 86,400 seconds; 1 week = 604,800 seconds; 1 average year = 31,557,600 seconds (about π x 10^7, a handy approximation physicists love). Going the other way, 100,000 seconds is 27.78 hours — just over a day and three hours — the kind of figure that appears in project estimates and server uptimes.
Practical uses cluster around billing, planning, and payroll: converting 2.5 hours to 150 minutes for a timesheet, turning a 90-day project into 12.86 weeks for a Gantt chart, or expressing a machine's 10,000-hour service interval as 1.14 years of continuous operation (10,000 / 8,766 = 1.141, using 8,766 hours per average year). Note that time zones and daylight saving are offsets, not conversions — this calculator converts durations, not clock times.
Every unit converts through seconds: 1 minute = 60 s, 1 hour = 3,600 s, 1 day = 86,400 s, 1 week = 604,800 s. The result is value × factor[from] ÷ factor[to].
Multiply by 60: 2.5 x 60 = 150 minutes. To seconds: 150 x 60 = 9,000 seconds, or directly 2.5 x 3,600 = 9,000 seconds. This is the timesheet conversion freelancers do daily: 7.5 hours becomes 450 minutes, and a 45-minute meeting is 0.75 hours. For billing at an hourly rate, always convert minutes to decimal hours first — 1 hour 20 minutes is 1.333 hours, and at $60/hour that is exactly $80, with no rounding disputes to slow down invoicing.
Divide by 7: 90 / 7 = 12.857, rounded to 12.86 weeks — about 12 weeks and 6 days (0.857 x 7 = 6 days). Project planners use this constantly: a '90-day' quarter is not 12 weeks but 12.86, and the missing six days explain why quarterly plans always feel tight. In months, 90 / 30.436875 = 2.96 average months — essentially three months, which is why business quarters are defined as three calendar months rather than 90 days.
120 minutes. Enter 2, choose hours → minutes.
7 days, of course — enter 1, choose week → day. Weeks here are exactly 7 × 24 hours, ignoring daylight-saving quirks.
Exactly 86,400 — enter 1, choose day → s. That's 24 × 60 × 60.