What Is Deuce in Tennis? Scoring Rules Fully Explained

Deuce is the score 40–40 within a single tennis game, where both players are tied and neither can win on the next point alone. From deuce, one player must win two points in a row to take the game: the first earns “advantage,” and the second closes it out. If they lose that second point, the score goes back to deuce — a cycle that can repeat many times.

How tennis scoring works up to deuce

Within a single game, tennis names points instead of just counting them:

Points Won	Score Name
0	Love
1	15
2	30
3	40
3 (tied)	Deuce (40–40)

Normally four points wins a game. But once both players reach 40 — three points each — a simple four-point finish line no longer applies. That tie is deuce, and it forces the game to keep going until someone builds a clear cushion.

What happens after deuce

From deuce, a player needs a two-point margin to close out the game:

1. Deuce (40–40): The score is level.
2. Advantage: One player wins a point and holds “advantage” (or “ad”).
3. Game: If the player with advantage wins the next point too, the game is over.
4. Back to deuce: If the other player wins that next point instead, the score resets to deuce.

There is no cap on how many times this cycle repeats under traditional scoring. Games that stretch 10, 15 or more points past the first 40–40 do happen at the professional level, occasionally running to 20-plus deuces.

Advantage in vs. advantage out

Two shorthand phrases tell you who is ahead once the game passes deuce:

• Ad in (or “advantage server”): The server holds the advantage.
• Ad out (or “advantage receiver”): The receiver holds the advantage.

They are a quick way for players and spectators to track who is one point from winning the game at any given moment, without waiting for the full umpire call.

The no-ad rule

Some formats skip the deuce cycle entirely using no-ad scoring:

• At 40–40, the very next point — a single deciding point — wins the game.
• There is no advantage point and no bouncing back to deuce.
• The receiving side chooses which half of the court to return from.

No-ad scoring keeps matches from running long, so it is standard in most professional doubles (including the ATP and WTA tours as of 2026) and common in college and recreational leagues. In mixed doubles, the deciding point is served to the receiver of the same gender as the server.

Why is it called deuce?

Most accounts trace “deuce” to the French deux, meaning two — a nod to the two consecutive points required to close out the game from that tied position. A competing theory links it to old English card-game terminology, but the French origin is the one most commonly cited.

Deuce in a tiebreak

Tiebreaks do not use the word “deuce” at all. Points are counted straight up (1, 2, 3…), and once the score reaches 6–6, a player still needs to win by two clear points. It is the same underlying win-by-two idea as deuce, just labelled differently: 6-all, then 7–6, 8–7 and onward until someone opens up that two-point gap.

Related terms and common misconceptions

Deuce is often confused with a tiebreak, but they are separate mechanisms: deuce governs a single game, while a tiebreak decides a tied set. A common mistake is assuming a game must end after four points — deuce exists precisely because a close game cannot end on a single point. Terms worth knowing alongside deuce include “advantage” (the one-point lead after deuce), “break point” (a chance to win the opponent’s service game), and “game point” (any point that would win the game if taken).