What is the probability of getting heads in a coin toss?

If you answered 50%, you wouldn’t be as smart as 9 year old me.  You see research has come out that essentially says that we all pretty much toss a coin the same way every time.  So there is actually a 51% chance that the coin will turn up the same side that you initially have the coin.

But the metaphor of a coin flip for randomness remains unquestioned. We use coin tosses to settle disputes and decide outcomes because we believe they are unbiased with 50-50 odds.Yet recent research into coin flips has discovered that the laws of mechanics determine the outcome of coin tosses: The startling finding is they aren’t random. Instead, for natural flips, the chance of a coin coming up on the same side as it started is about 51 percent. Heads facing up predicts heads; tails facing up predicts tails.

Personally I noticed this phenomena as a kid and could land a coin that was tails up back to tails after a flip about 75% of the time.  Naturally I used this to my advantage when doing coin tosses for playing football or other “who goes first” activity.

I would always start with tails up because more often than not when you flip a coin, people  seem to always say “heads”.


Too bad I wasn’t smart enough to publish my research.

20 Responses to “What is the probability of getting heads in a coin toss?”

  1. Time to win some coin toss bets 😀

  2. Tails never fails. 😀

  3. I always have better luck with tails.

  4. I always call tails and seem to win more than I lose, but the real test to this will be if NFL teams start to only call heads.

  5. The probability of me getting head is close to nil.

    Oh, wait! Different blog. I read it wrong. Sorry for the confusion.

  6. Well it just goes to show that you can argue with me but you can’t argue with research

  7. spilledinkguy Says:

    I always call the edge … I know that some day it’s really gonna’ happen! 🙂

  8. Know your audience. If your buddy tries to outthink you and call tails then start with heads up.

  9. Ah, the joys of growing up with mathematicians. Nobody was allowed to “choose” which way up the coin started either, or it wouldn’t be “random.”

  10. So Bearman, whats the odds of scissors, paper, rock?

  11. I prefer the “what number am I thinking of” method, because I always seem to win.

  12. So what about rock, paper, scissors, huh?

  13. […] Bearman Cartoons A Hack Cartoonist’s View of the World « What is the probability of getting heads in a coin toss? […]

  14. Howard Hendrickson Ph.D. Says:

    You all have neglected one other possible outcome. A coin can land on it’s edge. I have seen it happen, and even “called” it. Thought for food: ergo: the probabilty of a coin toss is NOT 50/50! Think about this for a minute and you will understand why: A cylinder is also a disc, and vice-versa. The formula for caluating volume and surface area is exactly the same. A disc is a cylinder which has less height…Have a nice day!

    • Howard I am buying the fact that a coin CAN land on it’s edge but unless you call “edge” everytime, I am not seeing how you could have “called it” Show me the youtube video..haha Thanks for stopping by.

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