Beginner

Deuce and Advantage

Also known as: deuce, ad in, ad out

Definition

Deuce is a tied score of 40-40 in a game. From there, a player must win two points in a row: the first for advantage, the second for the game.

When a game reaches 40-40, standard scoring requires a player to win by two points rather than simply winning the next point. Winning the point right after deuce gives that player "advantage" in the game. Informally, it is "ad in" if the server has the advantage, or "ad out" if the returner does. If the player with the advantage wins the following point, they win the game. If they lose it, the score returns to deuce. The sequence repeats until someone wins two points in a row. In theory, this lets a single game extend indefinitely. Long deuce battles with many advantages back and forth do occur, though they are relatively rare.

The deuce-and-advantage structure is one of the defining features of traditional tennis scoring. No-ad formats settle the game on a single point instead. Deuce and advantage rewards players who can perform well under repeated close-game pressure. Commentators and coaches often discuss momentum within a deuce sequence. A player who has just saved several advantage points may carry a psychological edge into the next one, even though each point technically starts even.

Example

At 40-40, the server wins the next point to go up advantage. The returner then wins the following point to bring it back to deuce. The game continues until one player wins two points in a row.

Why it matters

Deuce situations are recurring high-pressure moments within a match. How a player performs in extended deuce games is a useful signal, separate from their overall point-winning percentage.

Frequently asked questions

Can a game go on forever at deuce?

In theory, yes — there's no cap on how many times the score can return to deuce, since a player must win by two clear points. In practice, most games resolve within a few deuce exchanges.

What's the difference between "ad in" and "ad out"?

"Ad in" means the server has the advantage; "ad out" means the returner does. Both describe the same 40-40-plus-one-point score from different perspectives.