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Convert seconds, minutes, hours, days, weeks, months and years.
Convert seconds, minutes, hours, days, weeks, months and years.
Enter values above and click Calculate — results will appear here with the formula explained.
Most time units divide cleanly — 60, 60, 24, 7 — until calendar reality interrupts. Months range 28–31 days, so converters adopt the average: 30.44 days (365.25 ÷ 12). Years carry the .25 leap allowance for long-run accuracy.
Treat month/year outputs as planning approximations. A 'six-month' project quoted at 182.6 days will actually land wherever its specific six months fall — check a calendar when precision matters.
Why months refuse to behave: twelve 30-day months total 360, leaving five-plus days orphaned — lunar cycles (~29.5 days) and Roman politics shaped the uneven calendar we inherit. February absorbs the adjustment (28, sometimes 29), while July and August both run 31 by imperial vanity. Any converter must average; this one uses 30.44 days.
Leap machinery explained: every 4th year adds Feb 29, except century years unless divisible by 400 (2000 leap, 1900 not). The 365.25-day year averages this correctly; GPS and financial systems additionally track leap seconds (27 added since 1972, now being retired) — irrelevant here, where day-level granularity rules.
Seconds-scale anchors: 86,400 per day (except leap-second days), 604,800 per week, ~2.63M per average month, 31.56M per year. Millisecond and microsecond conversions serve developers timing code; hour/minute/second splits serve timesheets, races and cooking timers — same factors, different human contexts.
Payroll and billing conventions layer on top: 40-hour weeks, 2,080-hour years (40×52), 173.33-hour months (2,080÷12) for salary math, and billable 6-minute (0.1h) legal increments. These are contractual definitions, not physical ones — confirm which convention a timesheet or invoice uses before converting.
Convert seconds, minutes, hours, days, weeks, months and years. Formula: fixed seconds per unit. Example: 90 minutes equals 1.5 hours or 0.0625 days.
Most time units divide cleanly — 60, 60, 24, 7 — until calendar reality interrupts. Months range 28–31 days, so converters adopt the average: 30.44 days (365.25 ÷ 12). Years carry the .25 leap allowance for long-run accuracy.
Treat month/year outputs as planning approximations. A 'six-month' project quoted at 182.6 days will actually land wherever its specific six months fall — check a calendar when precision matters.
Why months refuse to behave: twelve 30-day months total 360, leaving five-plus days orphaned — lunar cycles (~29.5 days) and Roman politics shaped the uneven calendar we inherit. February absorbs the adjustment (28, sometimes 29), while July and August both run 31 by imperial vanity. Any converter must average; this one uses 30.44 days.
Leap machinery explained: every 4th year adds Feb 29, except century years unless divisible by 400 (2000 leap, 1900 not). The 365.25-day year averages this correctly; GPS and financial systems additionally track leap seconds (27 added since 1972, now being retired) — irrelevant here, where day-level granularity rules.
Seconds-scale anchors: 86,400 per day (except leap-second days), 604,800 per week, ~2.63M per average month, 31.56M per year. Millisecond and microsecond conversions serve developers timing code; hour/minute/second splits serve timesheets, races and cooking timers — same factors, different human contexts.
Payroll and billing conventions layer on top: 40-hour weeks, 2,080-hour years (40×52), 173.33-hour months (2,080÷12) for salary math, and billable 6-minute (0.1h) legal increments. These are contractual definitions, not physical ones — confirm which convention a timesheet or invoice uses before converting.
90 minutes equals 1.5 hours or 0.0625 days. A 90-day trial spans 12.86 weeks — closer to three months minus a few days than 'three months' implies. A 2,080-hour work year is 86.67 twenty-four-hour days of pure labor — the number behind every salary-to-hourly conversion.
Formulas are standard public references (see our methodology). External standards are cited in the text where they apply.
Last reviewed: September 2026 · Report an error