Convert between seconds, minutes, hours, days and weeks instantly.
This converts between seconds, minutes, hours, days, weeks, months and years. The first four are exact; the last three are not, and the difference is worth understanding before you rely on a result.
| Unit | Seconds | Minutes | Hours | Days |
|---|---|---|---|---|
| 1 minute | 60 | 1 | 0.0167 | 0.000694 |
| 1 hour | 3,600 | 60 | 1 | 0.0417 |
| 1 day | 86,400 | 1,440 | 24 | 1 |
| 1 week | 604,800 | 10,080 | 168 | 7 |
| 1 month (30 d) | 2,592,000 | 43,200 | 720 | 30 |
| 1 year (365 d) | 31,536,000 | 525,600 | 8,760 | 365 |
A useful figure to carry around: there are 525,600 minutes in a year, and a nanosecond-to-century span is easier to reason about once you know a year is roughly pi times ten million seconds — 31.5 million against a true 31.4 million, accurate to half a percent.
A month has no fixed length. It ranges from 28 to 31 days, and the average across a Gregorian year is 30.437 days. This tool uses 30 days for a month and 365 days for a year, which is the common convention, but it means a result in months is an estimate rather than an exact conversion.
Years are almost as slippery. The Gregorian calendar year averages 365.2425 days, achieved by adding a leap day in years divisible by 4 except centuries not divisible by 400. The astronomical tropical year is about 365.2422 days, and the difference means the calendar drifts by roughly one day every 3,200 years.
For anything requiring precision — contract terms, interest accrual, age — count actual calendar dates rather than converting through an average month. Our date difference calculator does that properly.
Even the day is not perfectly constant. The Earth's rotation is gradually slowing and varies irregularly, so leap seconds have been inserted into Coordinated Universal Time since 1972 to keep atomic time aligned with astronomical time. Twenty-seven have been added to date, always on 30 June or 31 December, producing a minute with 61 seconds.
They cause real trouble in computing, since a great deal of software assumes every minute has exactly 60 seconds. Several significant outages have been traced to leap second handling. The international body responsible has voted to abandon the practice by 2035, allowing UTC to drift from solar time instead.
Timesheets and invoices frequently need decimal hours rather than hours and minutes. Divide the minutes by 60:
The reverse trips people up: 3.5 hours is 3 hours 30 minutes, but 3.30 hours is 3 hours 18 minutes. Reading a decimal as though it were minutes is a common billing error. Useful anchors are that 15 minutes is 0.25, 20 minutes is 0.33, 40 minutes is 0.67 and 45 minutes is 0.75.
Some scales worth having: a standard working year is about 2,080 hours (40 hours over 52 weeks), a working month roughly 173 hours, and one million seconds is about 11.6 days while one billion seconds is nearly 32 years.
31,536,000 for a 365-day year, and 31,622,400 for a leap year. A memorable approximation is pi times ten million, which is accurate to about half a percent.
30 days, which is the usual convention for unit conversion. Real months run from 28 to 31 days and average 30.437, so any result expressed in months is an approximation. Use a date calculator when exact calendar dates matter.
Divide the minutes by 60 and add. So 2 hours 45 minutes is 2.75 hours. Going back, 0.25 is 15 minutes, 0.5 is 30 and 0.75 is 45 — but 3.30 hours is 3 hours 18 minutes, not 3 hours 30.
An extra second inserted into UTC to keep atomic time in step with the Earth's slightly irregular rotation. Twenty-seven have been added since 1972, always at the end of June or December. The practice is due to be discontinued by 2035.
About 2,080 for a standard 40-hour week over 52 weeks, before subtracting holidays and leave. After typical annual leave and public holidays, 1,800-1,900 hours is a more realistic figure.