A standard tennis doubles court is 36 feet wide and 78 feet long (10.97 by 23.77 metres). That makes it 9 feet wider than a singles court, while the length stays the same. The extra width comes from the two strips along the sides called doubles alleys.
Those alleys are important during rallies, but they are not part of the service boxes. Knowing which lines count on a serve—and which count once the rally begins—makes the court easier to read, whether you’re playing doubles or setting up a court of your own.
Standard Tennis Doubles Court Dimensions
| Part of the court | Dimensions |
|---|---|
| Full doubles court | 36 × 78 feet (10.97 × 23.77 metres) |
| Singles court | 27 × 78 feet (8.23 × 23.77 metres) |
| Each doubles alley | 4.5 feet (1.37 metres) wide |
| Service box | 21 × 13.5 feet (6.40 × 4.11 metres) |
| Net height at the centre | 3 feet (0.914 metres) |
| Net height at the posts | 3.5 feet (1.07 metres) |
The court is 78 feet long from baseline to baseline. The net sits halfway along that length, so each side extends 39 feet from the net to its baseline. The service line is 21 feet from the net on each side.
What the Doubles Alleys Are For
The full doubles court is 36 feet wide. A singles court is 27 feet wide, so the difference is 9 feet in total: one 4.5-foot alley on each side. The alleys are sometimes called tramlines.
During a doubles rally, a ball that lands in either alley is in. That extra width gives players more room to angle shots away from their opponents, but it also means the team covering the middle has more ground to protect. Partners often need to communicate clearly about who will take a ball hit between them.
The alleys do not count when judging whether a serve is good. A legal serve must land in the diagonally opposite service box, between the singles sideline and the center service line, and between the net and service line. If it lands in the alley, it is a fault—even in doubles.
How the Service Boxes Are Measured
Each service box is 21 feet long and 13.5 feet wide. The center service line divides the service area into left and right halves, while the singles sidelines mark its outer edges. The doubles alleys sit outside those sidelines and do not widen the service boxes.
For example, when serving from the deuce court, the server aims diagonally into the receiver’s deuce-side service box. The serve can land anywhere inside that box, including on its boundary lines, but a ball landing beyond the singles sideline is out even if it touches the doubles alley.
Net Dimensions and Posts
The net is 3 feet high at its centre and 3.5 feet high at the posts. In a standard doubles setup, the net posts sit 3 feet outside the doubles sidelines. This keeps the net supported beyond the playing area while leaving the full court width available for rallies.
When singles are played on a court fitted with a doubles net, singles sticks are used to support the net at the correct position for singles. They are placed 3 feet outside the singles sidelines. This helps keep the net at the proper height for singles play rather than leaving it supported only at the wider doubles posts.
Why the Court Width Changes Doubles Tactics
The extra 9 feet can change the shape of a rally. A crosscourt shot has more room to travel into the alley, and a wide serve can pull the receiver farther from the centre. The server’s partner can then look for a volley into the open space.
That space comes with a trade-off: the wider court can leave a bigger gap between partners. Teams often use a simple rule—one player takes balls in the middle when they can reach them comfortably, while the other covers the outside. Good communication matters, especially when both players can attack the same ball.
The alleys also affect positioning. If both players crowd the centre, a well-placed shot down the line may reach the alley. If they spread too far apart, an opponent may find a gap between them. Doubles teams adjust their spacing based on the ball, their opponents’ positions and whether they are serving or returning.
Markings and Measuring the Court
Court dimensions are measured to the outside edges of the boundary lines. In practice, that means a ball touching a boundary line is considered in. The baselines run across the full width of the court, while the doubles sidelines mark its outer edges. The singles sidelines sit 4.5 feet inside them on each side.
If you are checking a court layout, start with the full outer rectangle: 36 feet wide by 78 feet long. Then measure 4.5 feet inward from each doubles sideline to find the singles sidelines. The service lines go 21 feet from the net, and the center service line divides each service area into two boxes.
These measurements describe the playing lines, not the extra space around the court. A facility needs additional room beyond the baselines and sidelines for players to move safely, but the amount available can vary between clubs and venues.
Frequently Asked Questions
How wide is a tennis doubles court?
A standard doubles court is 36 feet wide, or about 10.97 metres. It is 9 feet wider than a singles court, with a 4.5-foot alley added on each side.
How long is a doubles tennis court?
A doubles court is 78 feet long, or about 23.77 metres. It has the same length as a singles court.
Are the doubles alleys in during a serve?
No. A serve must land in the diagonally opposite service box, which ends at the singles sideline. The doubles alleys count once the serve is returned and a rally is underway.
How big is a doubles service box?
Each service box measures 21 feet long by 13.5 feet wide. The doubles alley is not included in that width.
Final Thoughts
A tennis doubles court measures 36 by 78 feet, with a 4.5-foot alley along each side. The court is wider than a singles court, but the service boxes stay within the singles sidelines. Remember that distinction and the lines become much easier to follow: the alleys are in during rallies, but out for serves.
