Time Converter
Convert between 11 units of time — from nanoseconds to decades. Includes seconds, minutes, hours, days, weeks, months, and years.
Quick conversions
All units
About the Time Converter
Time is one of the seven fundamental SI base quantities. The SI unit is the second, defined since 1967 by 9,192,631,770 oscillations of the caesium-133 atom. Larger units (minutes, hours, days) are derived from astronomical cycles and are not decimal, making time conversion slightly unusual compared to other unit systems.
Quick facts
- ›The second is defined by the caesium atomic clock, accurate to 1 second in 300 million years
- ›A tropical year (Earth's orbit around the Sun) is 365.2422 days — not exactly 365
- ›A leap second is occasionally added to UTC to stay in sync with Earth's rotation
- ›Light travels approximately 299,792 km in one second
Common uses: Science, engineering, project management, astronomy, programming, physics