# How many Hours are in a Year?

## Hours in a year calculation

### Gregorian calendar year

One calendar common year has 365 days:

1 common year = 365 days = (365 days) × (24 hours/day)
= 8760 hours

One calendar leap year has 366 days - occures every 4 years, when February has 29 days:

1 leap year = 366 days = (366 days) / (24 hours/day)
= 8784 hours

One mean calendar year has 8765.82 hours:

1 mean year = (365+1/4-1/100+1/400) days = (365.2425 days) × (24 hours/day)

= 8765.82 hours

### Julian year

Julian year is used for astronomical calculations (light year definition).

One Julian year has 8766 hours:

1 year = (365.25 days) × (24 hours/day) = 8766 hours

### Sidereal year

One sidereal year is the time it takes the Earth to do a single rotation around the sun.

One sidereal year has 8766.15264 hours:

1 year = (365.25636 days) × (24 hours/day) = 8766.15264 hours

### Tropical year

One tropical year is the time it takes the Earth to complete a single cycle of the 4 seasons.

One tropiical year has 8765.812536 hours:

1 year = (365.242189 days) × (24 hours/day) = 8765.812536 hours