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 is used for astronomical calculations (light year definition).
One Julian year has 8766 hours:
1 year = (365.25 days) × (24 hours/day) = 8766 hours
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
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