一個公曆年有 365 天:
1 common year = 365 days = (365 days) × (24 hours/day)
= 8760 hours
一個日曆閏年有 366 天 - 每 4 年發生一次,當二月有 29 天時:
1 leap year = 366 days = (366 days) / (24 hours/day)
= 8784 hours
一個平均日曆年有 8765.82 小時:
1 mean year = (365+1/4-1/100+1/400) days = (365.2425 days) × (24 hours/day)
= 8765.82 hours
儒略年用於天文計算(光年定義)。
一個儒略年有 8766 小時:
1 year = (365.25 days) × (24 hours/day) = 8766 hours
一個恆星年是地球繞太陽轉一圈所需的時間。
一個恆星年有 8766.15264 小時:
1 year = (365.25636 days) × (24 hours/day) = 8766.15264 hours
一個回歸年是地球完成 4 個季節的一個循環所花費的時間。
一個回歸年有 8765.812536 小時:
1 year = (365.242189 days) × (24 hours/day) = 8765.812536 hours