What Does 420 Mean? The Real Origin Story (and the Myths)

Updated October 2026

Short answer: 420 started in 1971 with five San Rafael High School students in California, nicknamed the Waldos, who met at 4:20 p.m. by a Louis Pasteur statue to search for an abandoned cannabis patch. The code spread through the Grateful Dead scene and went global after High Times printed a 4/20 flyer in 1991. It is not a police code.

Ask ten people at a sesh what 420 means and you'll get eleven answers. Police radio code. The number of chemicals in weed. Bob Marley's birthday. Something about Hitler. A hotel room at Woodstock. A Bob Dylan math problem.

Almost all of it is wrong. The real story is better anyway: five teenagers, a treasure map, a Grateful Dead connection and one magazine reporter who got handed a flyer in a parking lot. We're a grinder company, so we've personally heard every one of these myths at a trade show booth. Let's settle it.

The real origin: the Waldos of San Rafael High (1971)

In fall 1971, five friends at San Rafael High School in Marin County, California, used to hang out on a wall on campus, which is how they got the name "the Waldos." Their names were Steve Capper, Dave Reddix, Jeffrey Noel, Larry Schwartz and Mark Gravich.

According to the Waldos' own account to KQED, they got their hands on a hand-drawn map to a cannabis patch near Point Reyes. The grower, a member of the Coast Guard and the older brother of a friend, was ready to abandon it rather than risk getting caught. Free weed, if you could find it.

So the Waldos set a meeting time and place: 4:20 p.m., at the statue of Louis Pasteur on campus. That was right after classes and football practice, so everyone could make it. They'd meet, light up, and drive out to Point Reyes to search.

They never found the patch. But "420" stuck as their private code word for cannabis. "Got any 420?" could be said in front of parents and teachers without anybody catching on. It was, in Reddix's words, "our own little secret code."

How we know it's true

Lots of people claim to have invented things. The Waldos kept receipts: postmarked letters and other 1970s documents using "420," which they've shown to journalists and keep in a bank vault. The Oxford English Dictionary now credits students in San Rafael with the term, per KQED's reporting. It's the only origin story with paper evidence behind it.

How 420 escaped San Rafael: the Grateful Dead connection

A secret code among five teenagers doesn't go global by itself. It needed a very large, very touring, very cannabis-friendly network. Enter the Grateful Dead.

The Dead were based in Marin County, and the Waldos had connections. Dave Reddix's older brother was close with Dead bassist Phil Lesh, and Reddix himself later worked as a roadie for Lesh. Mark Gravich's father helped the band with real estate. The Waldos hung around rehearsals, the word "420" got around the band's circle, and from there it spread through Deadheads following the tour from city to city.

By the late 1980s, "420" was common slang among Deadheads, even if most of them had no idea where it came from.

How High Times made 4/20 a holiday

On December 28, 1990, High Times reporter Steve Bloom was walking around the parking lot before a Grateful Dead show at the Oakland Coliseum when somebody handed him a flyer. In Bloom's own account, it called April 20 "the grand master of all holidays" and invited everyone to meet "at 4:20 on 4/20 for 420-ing in Marin County" on Mount Tamalpais.

High Times printed the flyer in its May 1991 issue. The magazine kept using the number, and editor Steven Hager pushed 4:20 as the official time to light up. Once one of the biggest cannabis publications in the world adopts a number, everybody adopts the number.

One problem: the flyer also said 420 was police code. It wasn't, and Bloom later acknowledged that part was wrong. When the Waldos came forward with their evidence, High Times credited them as the inventors of 420. If you want the bigger picture of where High Times fits in cannabis history, check our cannabis history timeline.

420 myths, debunked

Things that sound like myths but are real

• California Senate Bill 420. In 2003, California passed SB 420, which set up its medical marijuana identification card program. Yes, really.
• Mile marker 419.99. The Colorado Department of Transportation got tired of people stealing its mile marker 420 sign and replaced it with a 419.99 sign around 2014. Idaho and Washington have dealt with the same problem.

How 4/20 became a worldwide holiday

Once High Times was on board, 4/20 spread fast through the '90s and 2000s. College campuses held smoke-outs at 4:20 p.m. Activists used the day for legalization rallies. Some of the best known gatherings over the years include Hippie Hill in San Francisco's Golden Gate Park, Civic Center Park in Denver, the University of Colorado Boulder campus and the Vancouver Art Gallery in Canada. Ann Arbor's long-running Hash Bash is in the same spirit, usually held in early April.

Today 4/20 is part protest, part festival, part marketing calendar. Dispensaries run their biggest sales of the year around it. Brands drop limited editions. And plenty of people just quietly mark 4:20 p.m. with a bowl and a nod to five teenagers who never found their treasure.

How to celebrate 4/20 legally

• Check your local law first. Adult-use rules vary a lot by state and city, and public consumption is banned in most places even where cannabis is legal. Federal law still treats adult-use marijuana as Schedule I.
• 21+ only. No exceptions, no "it's a holiday" loophole.
• Stay put. Don't drive high, don't fly with cannabis and don't carry it across state lines. If you're traveling for 4/20, read our cannabis travel guide first.
• Find a legal spot to consume. In some states, licensed lounges are an option. Our guide to cannabis consumption lounges covers where they exist and the etiquette.
• Host at home. Honestly the best option. Your couch, your music, your movie. Our best stoner movies list and stoner playlist have you covered.
• Buy from licensed shops. 4/20 deals are real, but so is sketchy product. Licensed, lab-tested flower is worth it.

The 4:20 sesh ritual: grind, roll, light at 4:20

The whole point of 420 was a meeting time. Show up, light up, go. So treat 4:20 like the Waldos did, and have everything ready before the clock hits it.

1. Grind at 4:15. Break flower into pea-sized pieces, pull the stems, load it loosely around the teeth. A few short twists back and forth, then a tap. Our grind guide shows how fine to go for joints, bowls and vapes.
2. Roll at 4:18. A medium-coarse grind rolls and burns evenly. A grinder with a built-in paper dispenser means nobody is hunting for papers at 4:19.
3. Light at 4:20. Pass it left. Toast the Waldos.
4. Save the kief. A 4 piece grinder's screen collects it all session long, so by the end of the night you've got a little bonus to sprinkle on the next bowl.

If you want to turn the sesh into an actual ritual instead of a rushed one, read how we think about mindful sessions.

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The 4/20 host grinder: 1 1/4 papers in the lid, an ashtray and rolling dish on top, and room for the whole circle.
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FAQ

What does 420 mean?

420 is slang for cannabis and for the time (4:20 p.m.) or date (April 20) people celebrate it. It started in 1971 with five San Rafael High School students who met at 4:20 p.m.

Is 420 a police code?

No. That claim came from a 1990 flyer and has been debunked. There's no police code 420 for marijuana.

Who invented 420?

The Waldos: Steve Capper, Dave Reddix, Jeffrey Noel, Larry Schwartz and Mark Gravich, students at San Rafael High School in California in 1971.

Why is April 20 weed day?

Because 4/20 matches the code. Deadheads promoted April 20 as a gathering day in a 1990 flyer, High Times printed it in 1991, and it grew into a worldwide holiday.

What time is 420?

4:20 p.m. That's the original Waldo meeting time, right after football practice let out.

Five kids never found their weed patch, and the whole world got a holiday out of it. Grind one up at 4:20 and raise a joint to the Waldos.

Keep reading

• The history of cannabis: a timeline from ancient hemp to legal weed
• How to roll the perfect joint
• Cannabis events and trade shows worth your time