Two people arrive at a public court, four show up for the next game, and someone points to the extra strips of court along each side. Do those lines change how the game is played? The short answer: singles and doubles use the same court, but the outer side lanes—the doubles alleys—count only in doubles rallies.
Knowing which lines are in play clears up close calls and helps you make better use of whatever court you’ve booked. Here’s how the boundaries, net setup, and a few key rules differ.
One court, two sets of side boundaries
A standard tennis court is 78 feet long. Between the outer doubles sidelines, it is 36 feet wide; between the inner singles sidelines, it is 27 feet wide. The extra 4½ feet on each side make up the doubles alleys.
| Feature | Singles | Doubles |
|---|---|---|
| Length | 78 feet | 78 feet |
| Width in a rally | 27 feet, between the singles sidelines | 36 feet, including both doubles alleys |
| Side boundary for rallies | Singles sideline | Outer doubles sideline |
| Legal serve target | Diagonal service box | Diagonal service box, not the doubles alley |
The baselines at the ends are the same for singles and doubles. It’s the side boundary that changes: a ball landing on the singles sideline is in for either format, while a ball landing in a doubles alley is in only during a doubles rally. In singles, that same alley is out.
Which lines count on a serve?
In both formats, the server must hit the ball diagonally into the service box opposite them. The service boxes are the same size in singles and doubles, and their outside boundary is the singles sideline—not the doubles sideline. So a serve that lands in the alley is out, even in doubles.
That catches players who assume the wider doubles court means a wider target from the first shot. It doesn’t. The alleys become available only after the serve has landed in the correct service box and the rally is underway. If the serve clips the line of the service box, it’s good.
Net setup on a public court
The net’s center should be 3 feet high. At the posts, it is 3 feet 6 inches high. On a properly equipped court, the net posts are set at the doubles sidelines. When playing singles on that wider court, the rules call for singles sticks to support the net at the right points, 3 feet outside the singles sidelines.
Many public courts don’t have singles sticks, so casual players often use the net as it stands. If you’re playing a friendly match, agree on that before starting. For a competition played under official rules, use singles sticks when required and available. In either case, don’t move the net posts or try to improvise a support that could damage the court or equipment.
How the extra width changes the game
The alleys add room for angles. In doubles, a player can pull opponents wide with a crosscourt shot or target the space beside a player at the net. That extra width also gives the defending team more court to cover, which is why doubles partners often communicate and shift together rather than treating the court as two separate halves.
Singles is narrower, but it can still demand plenty of running. Players often use crosscourt shots to move an opponent away from the middle, then look for a shorter ball to attack. A shot that lands in the alley might be a smart winner in doubles; in singles, it gives away the point. When you’re unsure, picture the singles sidelines as your rally boundaries.
A simple practice drill helps: have a friend call “singles” or “doubles” before each feed. Play the point using the called boundaries. It trains you to see the correct lines quickly instead of deciding after the ball bounces.
What stays the same—and what changes
Most of the basic rules don’t change with the number of players. The court length, service-box dimensions, scoring system, and one-bounce limit are the same. A ball that lands on a boundary line is in when that line marks the edge of the court being used.
Doubles has additional rules for serving and receiving. Partners take turns serving within their team’s service order, and the receiving team also follows a set order during a set. Partners can stand wherever they like on their own side, though they commonly choose positions that let one player cover the net and the other cover more of the baseline. Singles has no partner rotation to manage.
On a public court, those details matter less than agreeing on the format and keeping the game moving. Before a close match, confirm the score, serving order, and whether you’re using singles sticks if you’re playing singles. If there’s a dispute about a line call, make the call promptly and generously when you’re unsure.
Public-court tips for switching between formats
- Check the court before playing. Find the singles and doubles sidelines, service lines, and center service line. Faded paint can make the boundaries hard to spot.
- Call the format early. If four players are sharing a court, agree that the doubles alleys count only for the rally—not for the serve.
- Keep your calls consistent. Use the same boundaries for both teams, even when a disputed ball is close.
- Watch neighboring courts. A ball rolling onto another court can interrupt play or create a safety issue. Call “let” if it affects a point.
- Respect court time. Follow posted booking rules and have the next players ready to rotate in when your session ends.
Frequently Asked Questions
Can I play singles on a public doubles court?
Yes. Singles uses the inner singles sidelines on the same standard court. For official play, singles sticks are used to support the net at the correct points when required. Casual players often play without them if the court has none.
Are the doubles alleys in during a serve?
No. A serve must land in the correct diagonal service box, whose outer edge is the singles sideline. The doubles alleys count only after a legal serve has started the rally.
Is a ball on the singles sideline in during doubles?
Yes. The singles sideline lies inside the doubles court, so a ball landing on it is in during a doubles rally. The outer doubles sideline marks the edge of the full doubles court.
Does doubles use different scoring?
Usually not. Standard doubles uses the same game and set scoring as singles, though some recreational leagues or time-limited formats may use special rules. Agree on any local variation before the match.
Final Thoughts
Singles and doubles don’t require separate courts. The key difference is which side line marks the edge of a rally: the inner singles line for singles, and the outer doubles line for doubles. The serve still has to land inside the same diagonal service box in either format. Once you keep those two points straight, the lines on a public court are much easier to read—and close calls become less likely to turn into arguments.
