Game
The 60% coin
A coin lands heads 60% of the time. You start with $25 in play money and bet on heads every flip. You pick only how much to bet.
The game needs script to flip. The results of 2,000 games at each bet size are below.
How much of your balance do you bet on the next flip?
$25.00your balance
Your game: your balance after each flip.
A 20% bet is $5.00 right now. Change it between flips if you like.
Finish one game. Then see how each bet size does over 2,000 games.
The same bet, 2,000 times
Betting 20% on every flip hit the cap in 91% of games and went bust in 7%. The middle game ended at $250.
As of 11 Oct 2026Source computed on this page, a fair 60% coin, 2,000 seeded games per bet size
What this shows
Every bet size faces the same 60% coin. The bars show how 2,000 simulated games ended at each size.
At 10% a flip, 94% of games hit the cap and 0% went bust. At 20% the balance grows fastest, and 7% went bust. At 40% the losses bite harder than the wins help: 49% went bust. At 100% one tails ends the game, and 87% went bust.
The 20% is not a guess. For an even-money bet, the size that grows a balance fastest is the chance of winning minus the chance of losing. Here that is 60% minus 40%. Traders call the question position sizing.
People played this for real money
In a study by Haghani and Dewey, 61 people played this game for real money. Most were finance and economics students or young finance professionals. They had $25 and 30 minutes. 28% went bust and were paid nothing. 21% reached the $250 cap.
Source Haghani and Dewey, arXiv 1701.01427. Figures checked against the paper.
How it is played
Each flip bets a share of your balance. Heads adds the bet. Tails takes it. You can change the share between flips.
A game is up to 300 flips. It stops early at the $250 cap. Under $2 counts as bust.
Your own game is new every time. The bars come from 2,000 games per bet size with a fixed seed, so every visit shows the same bars.
Source computed on this page, a fair 60% coin