A court can look close to regulation and still play strangely if a baseline is a few inches out of place. Whether you’re laying out a new court, checking an old one, or marking temporary lines, the key is to measure from consistent reference points and square the corners before you paint or tape anything down.
Official tennis court dimensions
A regulation court is 78 feet long. The doubles court is 36 feet wide, while the singles court is 27 feet wide. Singles is not a separate, narrower rectangle: it uses the same baselines and a pair of inner sidelines. The strips between the singles and doubles sidelines are the doubles alleys.
| Part of the court | Regulation measurement |
|---|---|
| Overall length | 78 feet |
| Doubles width | 36 feet |
| Singles width | 27 feet |
| Each doubles alley | 4.5 feet wide |
| Net to each service line | 21 feet |
| Service-box width | 13.5 feet |
The net divides the court in half, leaving 39 feet from the net to each baseline. Each service line is 21 feet from the net, or 18 feet from its baseline. The center service line divides the space between the net and service line into two equal service boxes on each side.
What you’ll need
- A long measuring tape, ideally 100 feet or more, or a surveyor’s tape
- Stakes, cones, or weights to hold reference points
- String or chalk line for straight edges
- A carpenter’s square, laser, or a second tape for checking right angles
- Chalk or removable tape for a temporary layout
A helper makes the job easier, especially when stretching a long tape or string. Measure on a flat surface if possible. On a sloped or uneven area, a tape following the ground can give a different result from a true horizontal measurement, so use a laser or get help from someone who lays out courts professionally.
How to lay out the court
1. Choose your reference point and centerline
First decide where the court will sit, leaving room beyond the lines for players to run safely. The playing dimensions do not include that extra space. For a new build, check local facility requirements before settling on the overall site size; the safe area around the court matters just as much as the painted rectangle.
Mark the center of the planned net, then establish a straight line running lengthwise through the court. This is your centerline reference. Measure 39 feet in each direction from the net center to locate the two baselines. Check that the full distance between baseline reference points is 78 feet.
2. Mark the court’s width and square the corners
At each baseline, mark 18 feet to either side of the centerline for the doubles sidelines. Those marks create a 36-foot-wide court. For singles, measure 13.5 feet to either side of the centerline to locate the inner sidelines.
Before fixing the lines, confirm that the corners form right angles. One simple field check is the 3-4-5 method: measure 3 feet along one side from a corner and 4 feet along the adjoining side. The distance between those two marks should be 5 feet. You can use multiples—6, 8, and 10 feet, for example—for a more precise check. Another useful check is to compare the diagonals of the full doubles rectangle: each should be about 85 feet 11 inches. If the diagonals differ, adjust the layout until they match.
3. Add the service lines and center service lines
Measure 21 feet from the net toward each baseline and mark the service lines. They run across the court from one singles sideline to the other, so each is 27 feet long. Then mark the center service line between the net and each service line, dividing that area in half. It runs perpendicular to the net and is 21 feet long.
Finally, add a center mark at the midpoint of each baseline. It extends 4 inches into the court and helps players position themselves when serving. Once these internal lines are in place, check that they meet their intended reference points rather than relying on visual alignment alone.
Measure the lines consistently
Line width is part of the layout, not an afterthought. Under tennis rules, lines are generally between 1 and 2 inches wide, while the baseline may be up to 4 inches wide. The center service line and center mark are 2 inches wide. Use the same width throughout the layout and make sure the lines are clearly visible.
When marking a court, keep the official playing dimensions consistent with the outer edges of the boundary lines. In practice, court-installation plans may specify exactly which edge or line center to use as a reference, so follow the plan for the surface and marking system you’re working with. If you are repainting an existing court, measure its lines before covering them; otherwise, it’s easy to shift the boundaries unintentionally.
Common measuring mistakes
- Using the wrong width: The doubles court is 36 feet wide. The 27-foot singles court is defined by the inner sidelines.
- Placing the service line from the baseline: It is 21 feet from the net, not 21 feet from the baseline.
- Skipping the diagonal check: A rectangle can have the correct side lengths and still be skewed if its corners are not square.
- Forgetting line width: A line painted over a measurement can make the usable court slightly different from the intended dimensions.
- Confusing the court with the whole playing area: The 78-by-36-foot measurement covers the marked doubles court only. Players need clear space outside it.
These details affect play. A service line placed too close to the net changes the depth of the service box, while a narrow or crooked alley can make doubles feel cramped. It’s worth taking a few extra minutes to check the measurements before the lines become permanent.
Frequently Asked Questions
How many feet is a regulation tennis court?
The marked court is 78 feet long. It is 36 feet wide for doubles and 27 feet wide for singles, using the inner sidelines.
How far is the service line from the net?
Each service line is 21 feet from the net. Since the net is 39 feet from the baseline, the service line is also 18 feet from the baseline.
Can I measure a court with a regular tape measure?
Yes, if the tape is long enough and you can keep it straight and taut. A long surveyor’s tape is more convenient, and a helper can hold the far end steady. Check long measurements twice before marking.
Does the 78-by-36-foot size include space around the court?
No. Those are the playing dimensions for the doubles lines. The area beyond the baselines and sidelines is extra clearance, and the amount needed depends on the site and the facility’s requirements.
Final Thoughts
Start with the 78-by-36-foot doubles rectangle, find the singles sidelines inside it, and place each service line 21 feet from the net. Then square the corners, check the diagonals, and account for line width before making permanent marks. Careful measuring gives you a court that looks right and, more importantly, plays right.
