Perpetual Calendar

This Perpetual Calendar was made by the French company Sculptures-Jeux in 1991. It allows you to find out which day of the week an event happened, anywhere between 1600 and 2999. You just need to know the date.

There are 3 cylinders, which you rotate, in order to set the month, the year and the century. You then read off the day of the month on the left, and follow the line across the 3 cylinders, and it will lead you to one of the days of the week on the right.

So, if you want to know what day of the week it was on July 20th, 1969 (which was the day that Neil Armstrong walked on the moon) well, you set the dials, and discover… it was a Sunday. No batteries required, and it can even cope with Leap Years!

19 Responses to Perpetual Calendar

  1. Kairu Hakubi

    Ah but can it tell you when Sozin's Comet passed at the same time as an eclipse?

  2. Jettera Ismabash

    Tim, what's your mother's maiden name? And your 4 digit pin? just asking for resarch… thanks j

  3. Radek S

    wow that pc 😀

  4. Max Hunter

    why one would make it so difficult? we have other issues too to resolve dude

  5. Leo Salvador Buesing

    its good video this the first time to see like you have a video sir how to replicate that.or website how its made.thanks

  6. Tom P

    Lovely, how extraordinary.

  7. Clorox Bleach

    i read the title as "Perpetual Calculator"

  8. Wooktent

    Woah I need that!!!

  9. Suban Grg

    that was kind of my birthday date too

  10. thewuj14

    Hey we have the same birthday. Bill Cosby's birthday is also july 12

  11. bananamaniac2

    is it just me or are half his sentence gibberish

  12. Sora

    i want one of this

  13. Tihai Naaana


  14. Batfan1939

    I want a Matt Parker video on how this works!

  15. Pigeon

    Who was bored enough they created this device?

  16. Tony Flamingo

    omg Tim had the same birthday as me no way!

  17. Thatboywithalife


  18. Snakezombie

    0:19 attack on the mic

  19. Grelgor

    Happy Birthday, Tim

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