# In tennis how to find out the service side in the middle of the game?

I am new to tennis, both as a viewer and a player. I hope this is not the wrong place to ask a beginner question.

So what happens is, after serving the ball I am too invested in the game and I don't remember which side I served from last. That means I can't figure out where to serve from next. This is also true for when I am on the receiver end. I can't figure out which side of the court to stand on.

I couldn't find any trick for this on the internet after a quick search. How do you do it? Is there a way to "calculate" the service side from the current score?

The rules of tennis are that:

• The first point of a game is served from the right-hand side of the court.
• After that, sides alternate.

Therefore:

• Anything with an even number of points played (0-0, 15 all, 30 all, deuce, 30-0, 0-30, 40-15 and 15-40) is served from the right-hand side of the court - this is why it is sometimes known as the "deuce court".
• Anything with an odd number of points played (15-0, 0-15, 40-0, 0-40, 30-15, 15-30, 40-30, 30-40 and advantage for either player) is served from the left-hand side of the court - the "advantage court".
• Thank you for your answer! So does that mean players mentally keep track of the number of points played during the game and check whether it is even or odd to pick the side? Or they just look at the score and "calculates" the side? I mean what would be going through the player's mind while in the field? Commented Apr 10, 2021 at 16:28

Consider 40 as 45 as it should be (since it used to be 3/4 of an hour on a clock).

If the two numbers have the same parity (both odd or both even) then you will serve/receive from the right side.

For example,

Score Parity Service
30-15 even-odd left
0-30 even-even right
15-40 odd-odd° right

° because 40 is treated like 45