This category of measurement units is defined by the "time" type, which is an SI base quantity.

The SI base unit for time is the second.

You may also want to find out how many days
are between two dates on the calendar. Use the
**date calculator**
to get your age in days or measure the duration of an event.

Convert time zones and get the
**time change** for different countries or cities around the world.

If you are traveling, you can measure your
**travel time**
or compare the
**flight time**
to the
**driving time**
for your next trip.

A second of arc or arcsecond is a unit of angular measurement which comprises one-sixtieth of an arcminute, or 1/3600 of a degree of arc or 1/1296000 (approximately 7.7×10-7) of a circle. It is the angular diameter of an object of 1 unit diameter at a distance of 360×60×60/(2pi) (approximately 206,265 units), such as (approximately) 1 cm at 2.1 km, or, directly from the definition, 1 astronomical unit at 1 parsec.

anomalistic month

anomalistic year

century

day

decade

draconic month

draconic year

fortnight

Gaussian year

Gregorian month

Gregorian year

hour

Julian month

Julian year

lunar year

microsecond

millennium

millisecond

minute

nanosecond

quarter

second

shake

sidereal month

sidereal year

synodic month

tropical month

tropical year

week