Units of time converter
Type a number and pick a unit to see it in every other unit of time at once, from nanoseconds to millennia. Months and years use the average Gregorian calendar lengths (a year of 365.2425 days), which is what most converters use.
Units of time chart
| Unit | Equals |
|---|---|
| 1 millisecond | 1,000 microseconds = 1,000,000 nanoseconds |
| 1 second | 1,000 milliseconds |
| 1 minute | 60 seconds |
| 1 hour | 60 minutes = 3,600 seconds |
| 1 day | 24 hours = 1,440 minutes = 86,400 seconds |
| 1 week | 7 days = 168 hours |
| 1 fortnight | 14 days = 2 weeks |
| 1 month | 28 to 31 days (30.44 days on average) |
| 1 year | 12 months = 52 weeks and 1 day (2 in a leap year) = 365 or 366 days |
| 1 decade | 10 years |
| 1 century | 100 years |
| 1 millennium | 1,000 years |
Why months and years are averages
Calendar months run from 28 to 31 days, and years are 365 or 366 days, so "how many seconds in a month" has no single answer. Converters use the Gregorian average: 97 leap years every 400 years makes the average year 365.2425 days (31,556,952 seconds), and the average month one twelfth of that, 30.436875 days. For exact dates, use the date calculator or time duration calculator.
Where the second comes from
The second is the base unit of time in the International System of Units. Since 1967 it has been defined by atoms rather than the Earth's spin: exactly 9,192,631,770 oscillations of the radiation from a caesium-133 atom. Read more in how a second is defined, or browse the A to Z of time words.
Questions people ask
How many seconds are in a day?
86,400: 24 hours × 60 minutes × 60 seconds.
How many seconds are in a year?
31,536,000 in a 365-day year and 31,622,400 in a leap year. The Gregorian average year is 31,556,952 seconds.
How many weeks are in a year?
52 weeks and 1 day, or 52 weeks and 2 days in a leap year, which is about 52.18 weeks on average.
How many days are in a month on average?
30.436875 days, from the Gregorian average year of 365.2425 days divided by 12.
What is the smallest unit of time?
There is no official smallest unit. Scientists have measured events of a few zeptoseconds (10−21 seconds), and the Planck time, about 5.4 × 10−44 seconds, is often called the shortest meaningful interval in physics.