Why is the singles badminton court narrower than doubles?

With only one player covering the whole court in singles, a full-width court would create too much open space to defend. The narrower sidelines keep singles rallies competitive by requiring more precise placement rather than rewarding raw width.

Which lines are out of bounds in doubles that are in bounds in singles?

None are the other way around - doubles simply adds width (the outer side tramlines) that singles does not use, while trimming serve depth via the doubles long service line, which sits inside the outer back boundary.

Blog/Badminton Rules

BADMINTON RULES - COURT LINES

Singles vs Doubles
Badminton Court Lines:
Why They Are Different.

Q: Is the badminton court different for singles and doubles?

Yes. The singles court is narrower than the doubles court, using the inner side lines. The doubles court is wider but has a shorter serve-in depth, since the doubles long service line sits further forward than the singles back boundary.

Badminton is the only racket sport where singles is narrower but doubles is shorter for serving. Here is exactly why.

The short answer

The singles court is narrower than the doubles court (uses inner sidelines only), but doubles has a shorter serving depth (the doubles long service line sits in front of the very back line). Both changes exist to keep serves fair and rallies competitive for the number of players on court.

Nearly every other racket sport just adds width for doubles and leaves everything else the same. Badminton is unusual because it adjusts both width and serve depth, in opposite directions.

Why singles is narrower

With only one player defending the entire court, a full doubles-width court would leave far too much space open to be realistically covered. The narrower singles sidelines - about 46cm in from the outer doubles line on each side - keep the court demanding but fair for a single defender, rewarding precise shot placement rather than raw width.

This is why a shot that lands in the tramline is out in singles but in in doubles - it is entirely a function of which sidelines are active for the format being played.

Why doubles has a shorter serve

Doubles serves are hit underarm and tend to be shorter, low serves designed to just clear the net - a long serve in doubles is easy for the receiving pair to attack. The doubles long service line sits inside the outer back boundary specifically to stop serves from travelling all the way to the very back of the court, which would otherwise give servers an unfair depth advantage given how quickly doubles teams can attack a deep serve.

In singles, this shortened line does not apply - the serve can travel all the way to the true back boundary, since singles rallies rely more on depth to be competitive.

Do not memorise the lines - let the app handle serve tracking

The court lines themselves are a live-play call, not something a scoring app tracks. But keeping score correctly across format switches - singles one game, doubles the next - is exactly where Scorepion helps. It tracks the right scoring rules and serve rotation for whichever format you are playing, from your Apple Watch or Wear OS watch.