Flip a fair coin. Track your heads vs. tails statistics.
This tool uses your browser's cryptographic random number generator to produce a fair 50/50 coin flip. Each flip is completely independent of previous flips, with exactly equal probability of heads or tails. The simulator tracks your flip history, running totals, and current streak. You can flip a single coin or multiple coins simultaneously.
Click "Flip" for a single coin toss. The coin animates and lands on heads or tails. The history panel shows all previous flips, the running percentage of heads vs. tails, and the longest streak. You can flip multiple coins at once (2, 5, 10, or 100) to see distributions in action. For more complex probability questions, use the Probability Calculator.
A fair coin has exactly a 50% probability of landing heads and 50% tails on any single flip. However, real coins are not perfectly fair due to slight asymmetries in weight distribution. Research by Persi Diaconis at Stanford found that a coin is approximately 51% likely to land on the same side it started on, a phenomenon caused by precession during the flip. For practical purposes, this bias is negligible.
Common probability misconceptions arise with coin flips. The Gambler's Fallacy is the belief that after a streak of heads, tails becomes "due." Each flip is an independent event with no memory of previous results. The probability of getting 10 heads in a row is (1/2)^10 = 1/1024, but after flipping 9 heads, the probability of the next flip being heads is still exactly 50%.
Research by economist Steven Levitt (University of Chicago) found that people who made important life decisions by coin flip reported being happier six months later than those who maintained the status quo, regardless of which side the coin landed on. The act of committing to a decision may matter more than the specific choice. The Decision Maker offers more structured approaches to difficult choices, and the Probability Calculator can model complex probability scenarios.
Coin flipping has decided consequential events throughout history. The 1903 Wright brothers used a coin flip to determine that Wilbur would attempt the first powered flight (he crashed; Orville succeeded three days later). Portland, Oregon was named via coin flip in 1845 (the alternative was Boston). Professional sports use coin tosses to determine possession, draft order, and overtime advantages. In the NFL, the coin toss winner in overtime wins the game approximately 52% of the time under current rules, a slight but statistically significant advantage that has prompted multiple rule changes over the decades.
Coin flips illustrate core probability concepts. With a fair coin, the probability of heads on any single flip is always exactly 50%, regardless of previous results. This independence of events is a key concept: getting 10 heads in a row does not make tails more likely on the 11th flip (the "gambler's fallacy"). The probability of getting all heads in N flips is (1/2)^N: 25% for 2 flips, 12.5% for 3, 0.1% for 10, and about 1 in a million for 20. A coin flip is widely used as a fair randomization method in sports (NFL overtime, cricket innings), dispute resolution, and even political tie-breaking. Several U.S. election ties have been resolved by coin toss.