CoinFlipFree

A short history of the coin toss

People have been settling arguments with a flipped coin for around two thousand years.

A gentleman in a bowler hat points at a giant coin flipping through the air
A coin toss gives each side exactly the same chance.

Ship or head

The earliest known version comes from ancient Rome, where children and adults played a game called navia aut caput, "ship or head". Roman coins carried a ship on one side and the head of a ruler on the other. The modern words "heads" and "tails" come from the same idea: the obverse of most coins shows a head, and the reverse is the "tail" end.

Coin tosses that decided real outcomes

Coin tosses in sport

Almost every team sport that has ends, serves or a first turn uses a coin toss to start: football, cricket, rugby, hockey and American football all do. Its value is simple: it is quick, everyone understands it, and neither side can influence the result.

From pocket change to pixels

Today, many coin tosses happen on a phone. A well-built digital flip uses a cryptographic random number generator rather than a physical coin, which removes the tiny bias of a hand-flipped coin. You can try one on our flip a coin page, or read about the maths in is a coin flip really 50/50?

More free tools