This time converter converts seconds, minutes, hours, days, weeks, months and years in both directions — the unit-shuffling behind timesheets, project plans and “how many seconds is that, really” questions.
The Honest Conventions
Minutes and hours convert exactly (60, 3,600 s); months and years need a stated convention because calendars refuse to be uniform. This converter uses the astronomers’ Julian year (365.25 days, leap years averaged in) and the average month (a year ÷ 12 = 30.44 days) — the right choice for durations, rates and ages, and clearly labeled so date-precise work can use our Date Calculator and Time Calculator instead. Part of our Conversion Calculators collection.
Quick Reference
| 1 unit | = seconds | = minutes | = hours |
|---|---|---|---|
| 1 hour | 3,600 | 60 | 1 |
| 1 day | 86,400 | 1,440 | 24 |
| 1 week | 604,800 | 10,080 | 168 |
| 1 year | 31,557,600 | 525,960 | 8,766 |
Worked Examples (Verified)
- 90 minutes = 1.5 hours — the payroll classic (billing in decimal hours)
- 1 million seconds = 11.57 days — and 1 billion seconds is 31.7 years, the internet’s favorite scale shock
- 10,000 hours (the mastery myth’s number) = 416.7 days of continuous time, or 3.8 years at 50 working weeks × 50 hours — context the slogan omits
Related Tools
- Time Calculator — add and subtract durations
- Date Calculator — real calendar dates
- Conversion Calculators — the full collection
Frequently Asked Questions
How many seconds are in a day?
86,400 — 24 × 60 × 60. (The Earth’s rotation wobbles by milliseconds around it; leap seconds occasionally patch the difference, invisible at converter scale.)
How do I convert minutes to decimal hours?
Divide by 60: 90 minutes = 1.5 hours, 45 minutes = 0.75. Timesheets and billing live on this one division.
How many hours are in a year?
8,766 on the 365.25-day average (8,760 in a common year, 8,784 in a leap year). Salaried “2,080 work hours” is 40 × 52 of those.
Why is a “month” approximate in converters?
Because calendar months run 28–31 days. Converters use the average month (30.44 days); anything contractual or calendrical should be counted in actual dates.
How long is a million seconds, really?
11 days, 13 hours, 47 minutes — versus a million minutes at 1.9 years. Orders of magnitude in time sneak up through exactly these conversions.
Is this time converter free?
Yes — free, instant, no sign-up.