How Many Dominoes in a Standard Set?

A standard double-six set contains 28 dominoes.

Math

Each domino has two ends (0–6). Number of unique unordered pairs with repetition:

(n+1)(n+2)/2 where n=6 → 7×8/2 = 28.

Other Common Sets

• Double-nine: 55 tiles
• Double-twelve: 91 tiles
• Double-fifteen: 136 tiles
• Double-eighteen: 190 tiles

Double-six is the classic for most family games.