Tennis Court Dimensions, and the Numbers Nobody Quotes

Most pages on this subject give you the two headline numbers and stop. The two headline numbers are not what anyone actually needs, because the court is a rectangle drawn inside a much larger rectangle, and the larger one is the one that decides whether a court fits.

Every figure below is from the ITF Rules of Tennis, Rule 1, or from Tennis Australia's court and enclosure guidance.

What are the dimensions of a tennis court?

Measurement	Imperial	Metric
Length, baseline to baseline	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
Service line from the net	21 ft	6.40 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, outside the court	3 ft	0.914 m
Center mark on the baseline	4 in	10 cm

That is the entire court. Nine numbers, unchanged for well over a century, and the two most important ones were fixed in 1877 when a three-man subcommittee at the All England Club settled on a rectangle 78 feet by 27 feet for their first championship.

Why is the doubles court wider but not longer?

Because two players cover side to side better than they cover forward and back. Adding width is what makes the extra player worth having. Adding length would just make the rally longer for everyone.

The extra strip on each side is the doubles alley, 4 feet 6 inches wide. Nine feet of total width, split evenly, converts a singles court into a doubles court without moving a single other line.

This is why one set of markings serves both games, and why almost every court built is marked for doubles. Tennis Australia puts it plainly: for practical purposes the vast majority of courts are built to doubles dimensions.

How high is the net, and why does it sag?

Three feet six inches at the posts, three feet at the center, held down tightly by a strap. The dip is not slack rope. It is specified.

The effect is that the cheapest shot over the middle is also the lowest-percentage target, because the net is at its highest where the court is widest, and lowest where the angles are worst. Six inches of difference quietly shapes the whole geometry of a rally.

The posts sit 3 feet outside the doubles court on each side. If a doubles net is used for a singles match, two singles sticks prop it up at 3 feet 6 inches, placed 3 feet outside the singles sidelines, so the profile stays correct for the narrower court.

Where are the service lines?

Twenty-one feet from each side of the net, drawn only between the singles sidelines. That last detail is the one people get wrong: the service lines do not extend into the doubles alleys, which is why a serve landing in the alley is out in both games.

The area between the service line and the net is then split into two equal service boxes by the center service line, drawn parallel to the singles sidelines and halfway between them.

Each baseline carries a center mark 4 inches long, drawn inside the court. It is a small thing that exists solely so the server knows which half they are serving from, and it is why foot faults are judgeable at all.

How wide are the lines, and does it matter?

It matters more than almost anything else in Rule 1. Lines are between 1 and 2 inches wide, except the baselines, which can be up to 4 inches, and the center service line and center mark, which are 2 inches.

Then the rule that makes the widths load-bearing: all court measurements are made to the outside of the lines. The line is inside the court it bounds.

That is the entire reason a ball clipping the outer edge of a baseline is in. The court legally ends at the far edge of the paint, so up to 4 inches of baseline is playable surface. Over a season that is a meaningful amount of tennis.

How much space do you actually need?

Considerably more than 78 by 36 feet, and this is the figure nobody quotes. Players run past the baseline, so run-off is not optional space, it is part of the court.

Requirement	Club or recreation	ITF level	Stadium court
Total area	34.77 by 17.07 m	36.6 by 18.3 m	40.23 by 20.11 m
Run-off behind the baseline	5.48 m	6.4 m	8.23 m
Run-off at the side, to the fence	3.05 m	3.66 m	4.57 m
Minimum gap between unfenced courts	3.66 m	5.48 m	not applicable

So a club court needs roughly 594 square meters of ground for 261 square meters of playing surface. More than half the site is space to stop in.

Tennis Australia also gives a recommended total playing area of 36.57 by 18.29 meters, which is a neat 120 by 60 feet, with an absolute minimum of 34.75 by 17.07. If a site cannot take 114 feet of length, it cannot take a court.

Which way should a court face?

North to south, wherever possible. The stated aim is that the sun inconveniences players as little as possible, and the right answer depends on the time of day and year when the court will actually be used.

An east-west court puts the low sun directly behind one baseline for part of every day, which makes one end of the court unplayable at exactly the hours most people want to play. It is the single cheapest decision on the whole build and the most expensive one to reverse.

Is a tennis court flat?

No, and it is not supposed to be. Outdoor courts are built with a slope for drainage, generally around one percent or less, with the exact gradient depending on whether the base is permeable and the water drains down, or impermeable and it runs off the surface.

One percent over 78 feet is nearly 10 inches of fall, which is a lot more than it sounds and completely invisible to anyone playing. A court that looks perfectly level is doing quiet work every time it rains.

What else does Rule 1 specify?

More than you would expect for a rectangle. The net cord can be at most a third of an inch thick. The strap can be at most 2 inches wide. The band across the top is between 2 and 2.5 inches deep on each side, and the strap and band must be completely white.

Net posts may not exceed 6 inches square or in diameter; singles sticks may not exceed 3 inches; and neither may rise more than 1 inch above the net cord. Every line must be the same color, clearly contrasting with the surface.

And no advertising is permitted on the court, net, strap, band, posts or singles sticks, outside the narrow exceptions the rules set out. Whatever else tennis has sold, the playing surface itself is still protected.

Why does the geometry make good wall art?

Because it is one of the few sports diagrams that reads as pure design. A tennis court is nested rectangles, one line of symmetry, two colors. Drawn accurately it looks like something a modernist designed on purpose, which is why court plans hang well in rooms that have nothing to do with sport.

1. A court plan is wide, not square. Give it a run of wall: above a console, a sideboard or a bed.
2. Overhead plan views suit a hallway. Ground-level court photography needs a room people sit in.
3. Clay, grass and hard courts give three completely different palettes. Pick the one that matches the room, not the one you play on.
4. Keep it away from other line-heavy art. Two diagrams on one wall cancel each other out.

The full range is in the tennis wall art collection, the wider category is covered in choosing sports wall art, and the sizing logic is in the canvas size guide.