When to flip a coin
Coin flipping is one of humanity's oldest methods of random decision making, dating back to ancient Roman times when it was called "navia aut caput" (ship or head). It's a fair, unbiased way to make a 50/50 decision when you simply cannot choose between two options. Whether deciding who pays for dinner, who goes first in a game, or which of two paths to take — a coin flip provides an instant, impartial verdict.
Is a coin flip truly random?
Physical coin flips can actually be biased — research suggests a coin is slightly more likely to land on the same side it started on. This digital coin flip uses Math.random(), which in modern browsers is based on cryptographically secure pseudo-random number generation. Each flip is completely independent, with exactly a 50% probability of heads and 50% probability of tails.
Tracking your flips
The heads and tails counters track your flip session. Over a small number of flips you'll often see streaks and uneven distributions — this is normal and expected from random processes. Over hundreds of flips, the counts will converge toward 50/50. This is a great illustration of the Law of Large Numbers in probability theory. Use "Reset Stats" to start a fresh counting session.
Other uses
Coin flips are used in sports (deciding possession at kickoff), games (determining turn order), teaching probability concepts, and resolving deadlocks in group decision making. Some people use repeated coin flips to add randomness to choices where a single flip feels too consequential — for example, flipping three times and going with the best of three.