This year, 5779, is the longest possible year on the Jewish calendar. Not only is it a leap year, but Cheshvan and Kislev both have 30 days, for a total of 385 days. How often does that happen?

1 Answer 1


It happens in 1371/8512 years, which is about 16.1%.

  • 5
    Could you add something about how you arrived at (or sourced) that number? Mar 3, 2019 at 2:01
  • Where do you get 1371/8512 from? My reading of the Tur’s chart gives 40/247, which is slightly off but still rounds to 16.1%. Where does the difference come from? (And what does 8512 represent? I know of 19 year cycles, 247 year cycles, and over 600K year cycles, but 8512 is new to me.)
    – DonielF
    Mar 3, 2019 at 2:51
  • @doni the difference is from judaism.stackexchange.com/q/64074/759 and see edits
    – Double AA
    Mar 3, 2019 at 3:07

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