Year (yr)

Definition

A conventional average of 365.25 days (the Julian year); a common calendar year is 365 days, a leap year 366.

History

The year is the time the Earth takes to orbit the Sun, about 365.24 days. The calendar keeps step with 365-day common years and 366-day leap years, which average to 365.25 days over a four-year cycle.

Where it is used

Years measure age, long durations, interest and anything counted across seasons.

Typical uses include age, long durations, interest.

Conversion pages

These pages convert year to or from another unit in time.

No conversion pages use this unit yet.

Other Time units

• Second (s)
• Minute (min)
• Hour (h)
• Day (d)
• Week (wk)
• Month (mo)

Sources

• Julian year (IAU/ISO) IAU/ISO 80000-3 Julian year: 1 a = 365.25 d exactly, a convention for expressing durations. The average month here is that year divided by 12. Neither is an SI unit. · Dataset reviewed Sep 18, 2026