Tennis court dimensions: every measurement explained

Full-size tennis court dimensions are 78 feet (23.77 m) long by 27 feet (8.23 m) wide for singles, widening to 36 feet (10.97 m) for doubles. The net stands 3 feet 6 inches (1.07 m) at the posts and 3 feet (0.914 m) at the center.

Tennis court dimensions in feet and meters

Tennis court size is fixed by the ITF Rules of Tennis, the same layout for a public park court and a Grand Slam show court. The length never changes between formats. Only the width does, and only because two strips down the outside switch from out to in.

Measurement	Feet / inches	Meters
Court length (singles and doubles)	78 ft	23.77 m
Width, singles	27 ft	8.23 m
Width, doubles	36 ft	10.97 m
Doubles alley, each side	4 ft 6 in	1.37 m
Baseline to net	39 ft	11.89 m
Service line to net	21 ft	6.40 m
Baseline to service line	18 ft	5.49 m
Service box, each	21 x 13 ft 6 in	6.40 x 4.11 m
Net height at the posts	3 ft 6 in	1.07 m
Net height at the center	3 ft	0.914 m
Net post center, outside the sideline	3 ft	0.914 m
Net length, doubles court	42 ft	12.80 m
Playing surface, singles	2,106 sq ft	195.6 sq m
Playing surface, doubles	2,808 sq ft	260.8 sq m

Tennis court markings and lines explained

Here's one half of the court, from the baseline down to the net. The other half mirrors it exactly.

   |<---------- 36 ft / 10.97 m  DOUBLES ----------->|
             |<- 27 ft / 8.23 m  SINGLES ->|
   +---------+-----------------------------+---------+  <- BASELINE
   |         |                             |         |       ^
   | doubles |        no-man's-land        | doubles |       | 18 ft
   |  alley  |          (no lines)         |  alley  |       | 5.49 m
   |  4.5 ft |                             |  4.5 ft |       v
   |         +--------------+--------------+         |  <- SERVICE LINE
   |         |              |              |         |       ^
   |  1.37 m |   service    |   service    |  1.37 m |       | 21 ft
   |         |     box      |     box      |         |       | 6.40 m
   |         |  13 ft 6 in  |  13 ft 6 in  |         |       v
   +---------+--------------+--------------+---------+  <- NET
                            ^
                   center service line

Baselines close each end of the court, 78 feet apart, painted the full 36-foot width so they serve both formats. You serve from behind one.

Sidelines come in pairs. The inner pair, 27 feet apart, bounds the singles court. The outer pair, 36 feet apart, bounds the doubles court. The 4-foot-6-inch strip between them on each side is the doubles alley, or tramline.

Service lines sit 21 feet from the net on each side and run only the 27-foot singles width. They never extend into the alleys.

The center service line splits that 27-foot span into two service boxes 13 feet 6 inches wide. It runs from the net to the service line and stops there.

The center mark is a 4-inch stub on each baseline, pointing into the court. It marks the halfway point, and you have to serve from one side of it or the other — the detail most casual players ignore until someone calls a foot fault. Our guide to tennis serve rules covers what happens when you cross it.

There is no line between the service line and the baseline. That 18-foot strip is no-man's land — real, playable court that simply isn't marked.

Singles and doubles on the same court

Nobody repaints anything between formats. In singles the ball must land inside the 27-foot width, so a shot in the alley is out. In doubles the alleys are live and the same shot is good. The service boxes are identical in both, so a serve into the alley is a fault no matter how many people are on court.

That's the whole geometric difference. Serving order, court positioning, and the way tennis scoring rules play out are what actually change. If you're tracking a match, Tennis Scoreboard is a tennis scoreboard app for iPhone and Apple Watch that tracks match scores, and it keeps singles and doubles as separate match formats so the serve rotation follows the right one from the first point.

Tennis net height and post placement

The net is 3 feet 6 inches (1.07 m) at the posts and 3 feet (0.914 m) at the center, where a strap holds it down. A net measuring 3 feet in the middle isn't sagging — that dip is written into the rules, and it's why the middle of the net is the safest place to hit.

Post centers go 3 feet (0.914 m) outside the sideline. On a doubles court that puts them 3 feet beyond the 36-foot width, giving a net 42 feet (12.80 m) long. A court built for singles only puts them 3 feet outside the 27-foot width, for a 33-foot (10.06 m) net.

When singles is played on a court set up for doubles, singles sticks prop the net to 3 feet 6 inches at points 3 feet outside each singles sideline. Without them the net runs lower across the singles width than the rules intend. Net posts may be up to 6 inches (15 cm) square or in diameter and singles sticks up to 3 inches (7.5 cm), and neither may stand more than an inch (2.5 cm) above the net cord.

Line widths and run-off space

Baselines may be up to 4 inches (10 cm) wide. Other lines run 1 to 2 inches (2.5–5 cm), except the center service line and center mark, which are fixed at 2 inches (5 cm). Measurements are taken to the outside of the lines, and the lines are part of the court: a ball touching any part of one is in.

The playing lines are not the whole footprint. Club and recreational facility guidance puts the minimum run-off at 18 feet (5.5 m) behind each baseline and 10 feet (3.05 m) at each side, which fences an area of roughly 114 x 56 feet (34.75 x 17.07 m). For ITF-level competition the margins rise to 21 feet (6.40 m) behind and 12 feet (3.66 m) at the sides, about 120 x 60 feet (36.58 x 18.29 m).

Squeeze the run-off and the court still measures correctly, but wide balls become unplayable and players start hitting fences. It's the number most backyard installs get wrong.

FAQ

How big is a tennis court in feet?

78 by 27 feet for singles and 78 by 36 feet for doubles. Length is the same in both. The extra 9 feet of width in doubles comes from two 4-foot-6-inch alleys, one on each side.

What are the dimensions of a tennis service box?

Each service box is 21 feet deep from the net to the service line and 13 feet 6 inches wide, or 6.40 by 4.11 meters. There are four of them, two per side, divided by the center service line.

How high is a tennis net in the middle?

3 feet (0.914 m) at the center strap and 3 feet 6 inches (1.07 m) where it meets the posts. Measure at the center — that's the one that drifts, since straps loosen and nets stretch over a season.

Is the doubles alley in or out?

Out in singles, in for doubles. The alley is only live once four players are on court, and even then never on the serve, which has to land in a service box.

How much space do you need to build a tennis court?

Plan for about 114 x 56 feet for a recreational court: the 78 x 36 playing area plus 18 feet of run-off at each end and 10 feet at each side. Competition venues want closer to 120 x 60 feet, using 21-foot and 12-foot margins.