Look at the middle of a tennis court’s baseline and you’ll see a short line pointing toward the net. That small mark helps players tell which side of the court they should serve from—and gives officials a clear reference when checking a foot fault.
The tennis court center mark is easy to confuse with the center service line, but the two have different locations and jobs. Here’s how to spot the center mark, what its official size is, and how it matters during a match or when laying out court lines.
What Is the Tennis Court Center Mark?
The center mark is a short line at the midpoint of each baseline. It points inward from the baseline, toward the net, and splits the space behind the baseline into two halves: the deuce side and the ad side.
Its main purpose is to help the server line up on the correct side of the court. Players serve from the deuce court when the score is even and from the ad court when it is odd. The center mark also helps define the server’s legal position behind the baseline.
Official Center Mark Size and Position
Under the standard Rules of Tennis, the center mark is 4 inches (10 cm) long and 2 inches (5 cm) wide. It is placed at the center of the baseline and extends into the court, perpendicular to the baseline. Its direction is parallel to the sidelines.
There is a center mark on both baselines, so players can use the same reference whichever end they are playing from. The mark is part of the court layout, but it is not a separate serving box or boundary line that runs all the way to the net.
Center Mark vs. Center Service Line
These two lines are easy to mix up because both sit near the middle of the court. The simplest way to tell them apart is by where they are:
| Line | Where to find it | What it does |
|---|---|---|
| Center mark | At the midpoint of each baseline | Shows the division between the two serving positions behind the baseline |
| Center service line | Between the net and the service line | Divides each service area into left and right service courts |
The center service line is much longer. It helps define where a serve must land. The center mark is just a short guide at the baseline. For example, a serve can land in the correct service box even if it crosses the net far from the center mark; the mark does not determine whether the serve is in.
How Players Use the Center Mark
Choosing the correct serving side
At the start of a standard game, the first serve comes from the deuce side—the server’s right when facing the net. Players then alternate sides after each point. A quick glance at the center mark helps a server find the halfway point of the baseline and avoid starting from the wrong side.
That reference is especially useful during a tense game, when players may be thinking about the score, the wind, or their serving routine. A player who regularly serves wide on the deuce side or toward the body on the ad side may also use the mark to keep a consistent starting position.
Checking foot faults
The server must stay behind the baseline and within the imaginary extensions of the sideline and center mark until striking the ball. A foot touching the baseline during the service motion can be a foot fault, as can stepping across the wrong side of the center mark. The server may move around behind the line, but cannot gain an unfair advantage by stepping into the court or beyond the permitted area before contact.
In a match without a chair umpire, players may not notice every small foot fault. Still, the center mark gives both players a visible reference if the server appears to be crossing too far toward the other half of the baseline.
Finding the Center Mark on a Court
Stand behind either baseline and look for the short line at its exact midpoint. On a court with clearly painted lines, it should be easy to spot. On a faded public court, check the middle of the baseline for a small perpendicular stripe; worn paint can make it hard to distinguish from cracks or surface scuffs.
On a doubles court, the baseline is the same for singles and doubles, so the center mark stays in the same place. It does not move when players switch from singles to doubles. If the mark is missing or badly worn, players can estimate the midpoint between the two sidelines, but a properly marked court should have the line at the baseline’s center.
Marking or Repainting a Center Mark
For a new or repainted court, accuracy matters more than the mark’s small size might suggest. Measure the baseline’s midpoint carefully, then lay out a 4-inch-long by 2-inch-wide mark perpendicular to the baseline, pointing into the court. Keep the edges straight and use paint intended for the court surface.
Before painting, confirm the court’s full layout and follow the surface maker’s instructions. A misplaced center mark can confuse serving positions, while an overly long mark may be mistaken for another court line. For a shared public court, use a qualified court contractor if the baseline or other markings also need repair.
Frequently Asked Questions
How long is a tennis court center mark?
The official center mark is 4 inches (10 cm) long and 2 inches (5 cm) wide. It sits at the midpoint of the baseline and extends into the court.
Does the center mark affect whether a serve is in?
No. The center mark does not define the service box or determine whether the ball lands in. The center service line and the other service-court boundaries are used to judge the serve’s landing spot.
Can a server stand on the center mark?
A server must remain behind the baseline and on the correct side of the center mark until hitting the ball. Stepping across the mark or touching the baseline before contact can result in a foot fault.
Is there a center mark on both ends of the court?
Yes. Each baseline has a center mark, giving the server a reference point at either end of the court.
Final Thoughts
The tennis court center mark is a small but useful part of the court layout. Found at the midpoint of each baseline, it helps players choose the correct serving side and provides a reference for the server’s position. Remember the key distinction: the center mark is at the baseline; the longer center service line divides the service boxes.
