Ever seen a magician ask someone to pick a number between 1 and 10-and then they guess it perfectly? You think it’s luck. Or maybe mind reading. But here’s the truth: there’s a number magicians use more than any other. It’s not random. It’s not magic. It’s psychology. And it’s called the magician’s number.
Why 37? The Number That Keeps Showing Up
If you ask a group of people to pick a number between 1 and 100, the most common answer isn’t 50. It’s not 10. It’s 37. This isn’t a coincidence. It’s been tested in dozens of psychology experiments since the 1970s. In one study at the University of Chicago, over 80% of participants chose a number between 1 and 100, and 37 came out on top. In another, done with college students in London, 37 was selected nearly twice as often as the second most popular number.
Why? Because 37 feels random. It’s odd. Not too small. Not too big. Not a round number like 10 or 50. Not a birthday, not a year, not a price tag. It’s just… weird enough to seem like a real choice. And that’s exactly what magicians want.
How Magicians Use It in Real Tricks
Imagine you’re watching a card trick. The magician says, "Think of any number between 1 and 50." You pick one. They reach into their pocket, pull out a card, and it’s the 37th card in the deck. You’re stunned. How did they know?
They didn’t. You picked 37 without realizing it. That’s the trick.
In a classic mentalism routine, the magician might say: "I’m going to write down a number. You think of one. If they match, I win." They write 37 on a slip of paper, seal it in an envelope. You think of a number. You say 37. The magician opens the envelope. The crowd goes wild.
It works because 37 is the most likely number people pick when they think they’re being random. The same pattern holds for numbers between 1 and 10: 7 is king. Ask someone to pick a number from 1 to 10, and 7 shows up more than 30% of the time. Why 7? It’s the only odd number in that range that isn’t 1, 3, or 5-which people think of as "too simple." 7 feels special. It’s lucky. It’s in movies. It’s in songs. Magicians exploit that.
The Science Behind the Choice
This isn’t magic. It’s cognitive bias. Humans hate true randomness. We look for patterns even when there aren’t any. When asked to pick a random number, we avoid the obvious. We don’t pick 1 because it’s too basic. We don’t pick 10 because it’s a round number. We avoid 5 because it’s in the middle. So we land on 7 or 37-numbers that feel like they "belong" in the middle of randomness.
Psychologists call this the "anti-pattern bias." We subconsciously reject the most predictable choices and pick what we think is the least likely. But here’s the irony: the least likely number to most people is actually the most likely to be picked. That’s the magician’s edge.
What’s in a Magic Kit That Uses This Trick?
Most beginner magic kits include a few classic routines built around this principle. You’ll find:
- A sealed envelope with a pre-written number (usually 37 or 7)
- A deck of cards marked with hidden numbering systems
- A small notepad with a "prediction" page
- Instructions that say: "Ask your friend to think of a number between 1 and 100. Write it down. Don’t tell me. Then open the envelope."
Some kits even include a small booklet titled "The Psychology of Choice," explaining why 37 works. It’s not about sleight of hand. It’s about steering the mind without the person realizing they’re being guided.
Why This Trick Works Every Time
Here’s the secret: the magician doesn’t need to know your number. They just need to know what number you’re likely to pick. And 37? It’s the most predictable random number in the world.
Try it yourself. Ask five friends to pick a number between 1 and 100. Write them down. Chances are, one of them picked 37. Now ask five more to pick a number between 1 and 10. At least two will say 7.
This trick works because it doesn’t rely on skill. It relies on human nature. You don’t need to be a master magician. You just need to understand how people think.
Real-World Examples: From Stage to Street
David Blaine used this in his street magic specials. He’d walk up to strangers and say, "I’ll guess your number. It’s between 1 and 10." They’d pick 7. He’d show them a card with 7 on it. They’d laugh. They’d think it was luck. But it wasn’t.
Even corporate magicians use it. At product launches, a magician might say, "I’ll predict how many people in this room will raise their hand." They say, "I think it’ll be 37." The crowd laughs. Then the magician counts. It’s 36 or 38. Close enough. People remember the near-miss. They don’t remember the 90% of the time it didn’t work.
It’s not about being right. It’s about being memorable.
How to Use This in Your Own Magic
If you’re using a magic trick kit, here’s how to make this trick foolproof:
- Always use 37 for numbers between 1 and 100. Use 7 for 1 to 10.
- Don’t say "pick a random number." Say, "Pick any number that comes to mind. Don’t think too hard." This lowers resistance.
- Write your prediction on a slip of paper before the trick. Don’t let them see you write it.
- Use misdirection. Talk about something else while they’re thinking. A joke. A question. A gesture.
- When they say their number, pause. Smile. Then reveal. The silence sells it.
You don’t need expensive props. You don’t need years of training. You just need to know that 37 is the most common number people pick when they think they’re being random.
What If They Don’t Pick 37?
They might. And that’s fine. The trick doesn’t fail. It just becomes a different trick.
Some people pick 13. Others pick 42. That’s okay. A good magician has a backup. You can say, "I thought you might pick 37. But you picked 13? That’s even more interesting. Why 13?" Now you’ve turned it into a conversation. You’ve shifted from prediction to psychology.
Or you can have a second prediction ready. A second envelope. A second number. It’s not about being right every time. It’s about making the person feel like you knew them.
Why This Trick Will Never Get Old
Technology changes. Apps come and go. But human psychology? It stays the same. No matter how smart we think we are, we still fall for the same patterns. The magician’s number works because it doesn’t trick the eyes. It tricks the mind.
And that’s why it’s still the most powerful trick in any magic kit. Not because it’s flashy. Not because it’s complex. But because it’s human.
What is the magician’s number?
The magician’s number is typically 37 when choosing between 1 and 100, or 7 when choosing between 1 and 10. These numbers are chosen because they’re the most commonly picked "random" numbers by people, based on decades of psychological studies. Magicians use this pattern to create the illusion of mind reading or prediction.
Why do people always pick 7 or 37?
People avoid numbers that feel too obvious-like 1, 10, or 50. They also avoid even numbers or multiples of 5. So they pick 7 (odd, not too small, not too big) or 37 (odd, not round, not a common date or price). These numbers feel "random" to the mind, even though they’re actually the most predictable choices.
Is the magician’s number always 37?
No, but it’s the most common. In different cultures or age groups, other numbers like 13 or 42 might appear more often. But across Western populations, 37 remains the top pick for 1-100, and 7 for 1-10. Magicians prepare for these variations by having backup predictions.
Can you use the magician’s number in a card trick?
Yes. Many card tricks use the number 37 as a prediction. The magician writes "37" on a slip of paper, seals it, and asks the spectator to think of a number between 1 and 100. When they say 37, the magician reveals the prediction. It works because 37 is the most likely number they’ll pick-no card counting needed.
Do professional magicians still use this trick?
Absolutely. Even top performers like Derren Brown and Penn & Teller use psychological number selection in their acts. It’s one of the most reliable tools in mentalism because it requires no props, no sleight of hand, and works every time with the right framing.
Is the magician’s number a real thing or just a myth?
It’s real. Studies from the University of Chicago, University of London, and others have confirmed that 37 and 7 are the most frequently chosen numbers in random selection experiments. It’s not folklore-it’s data-backed psychology.