The FAQ is currently in the process of being updated in the new system. We apologize for any inconvenience, and will be updating this page as soon as possible.

There are a variety of explanations besides the most common and the most elaborate, all much more interesting than "police code", and many plausible.

• Known Myths: It isn't police code. It isn't the number of chemicals in marijuana (315, not 420). And it isn't tea time in Amsterdam (that's 5:30). (Gerhard den Hollander).
• Length of buzz: In a study reportedly conducted on the effects of cannabis, one of the conclusions was that the effects last for 4 hours and 20 seconds, with onset in the first ten minutes, "coming up" for 5-10 minus, a plateau for 15-30, "coming down" for 45-60 minutes, and "after effects" for 30-60 minutes, with this graphic summarizing the high: (Cole Smith)
  
• Sixties Songs: For instance, Bob Dylan's famous "Rainy Day Women #12 and 35" is a possible reference, or source -- 12x35=420. And Stephen Stills wrote (and Crosby Stills Nash & Young performed) a song "4+20" (first recorded 7/16/69, released on Deja Vu 3/11/70) about an 24-year-old poverty-stricken man who started and finished with nothing. (Thanks to Sherry Keel 12/6/98; and Matt Cantor, 2/12/03.) Dylan aslo mentions "4 and 20 windows" in "The Balland of Frankie Lee and Judas Priest" (on John Wesley Harding).
• Older Verse: But 420 in poetry is older than that...
  • Greg Keller notes the old nursery rhyme line, "four and twenty black birds baked in a pie".
  • Revelation 5:14 (in the King James Version of the Christian Bible) reads, "And the four beasts said 'A-Men.' And the four and twenty elders fell down and worshipped him that liveth for ever and ever." (Travis Spurley 2/15/99) Mark 4:20 (which was printed on t-shirts in the late 1980s) reads ""Others like seed sown on good soil, hear the word, accept it, and produce a crop - thirty, sixty, or even a hundred times what was sown." (Althea Toldme) See also, 420 in the Bible.
  • In Midnight's_Children, Salman Rushdie wrote, "Inevitably, a number of these children failed to survive. Malnutrition, disease and the misfortunes of everyday life had accounted for no less than four hundred and twenty of them by the time I became conscious of their existence; although it is possible to hypothesize that these deaths, too, had their purpose, since 420 has been, since time immemorial, the number associated with fraud, deception and trickery." (Comet 2/14/98) Comet's "best guess is that this refers to something in Indian mythology or numerology, since the book is set in India and frequently involves Indian history, culture, and religion. Given the high interest in Eastern religion among the phish/dead community, this seems a likely origin of 420's current significance."
• Temporal Significance: "Hands on analog clock at 4:20 look like position of doobie dangling from mouth" "Larry in Tuscan" and Alex Mack 5/19/99). Disruptive students are out of detention and safetly away from school by 4:20, also rumored to be "the time that you should dose to be peaking when the Dead went on stage" Hart. "The Waldos" were a group of teens back in the 70's that lived in San Rafael, CA. 420 was the way they talked about pot in front of teachers, non-smoking family members etc. Also it was the time of day they could just go relax, and get baked." ("PhunkCellar") Jamaicans purportedly "worked till 4 then walked home then lit up. They would talk 420 like our parents talked about after 5. That's when partying began" "Larry in Tuscan"). Albert (not Abbie) Hofmann supposedly first encountered LSD at 4:20 p.m. on 4/19/1943 (Bart Coleman citing Storming Heaven by Jay Stevens, recommended by Mickey Hart in Planet Drum). Surrealist painter Miro was born April 20, 1893. And www.filmspeed.com says the propoganda film Reefer Madness has a copyright date of April 20, 1936 (i.e. 4/20). (PW)
• Misc: Could be that it comes from hydroponics, the practice of cultivating plants in water often used by indoor marijuana cultivators, since 4 is used for H on a calculator (420/H20). (Nick Lowe 3/30/00) The number 80 (eight) is "quatre vingt" (pronounced "cah-truh vahn"), meaning "four (times} twenty". Dan Nijjar 1/27/00 (No connection yet between the number 80 and pot. A quarter pound is roughly 120 grams, rounding quarter-ounces to 7.5.) The titanic was supposed to arrive 4/20/1912. (Thanks to RB.) Perhaps the heavy use of vt420 terminals in the Berkeley area is to blame? (BTW, 420 in binary code is 110100100.)

Related FAQ pages: