Last checked: August 2026 · Written by the player-led team at Badminton House
Quick answer
Use court geometry, not colour alone: a boundary line is in, and singles and doubles use different long service boundaries. Regulation badminton lines are 40 millimetres and preferably white or yellow, but that does not create a universal shared-gym colour code.
Start with A boundary line counts as in
Read a multi-use gym from court geometry first. The aim is to identify the badminton court before serving, then agree a temporary local reference if the paint cannot be read confidently; it is not to infer a universal colour code from one hall.
- Find the net posts first and trace the two sidelines they define.
- Find the short service line and centre service line, then follow each service court toward the back boundary.
- Choose singles or doubles before deciding which long service boundary applies to the serve.
- If a necessary marking is obscured, agree a visible temporary reference with opponents before the first serve and ask the facility how it wants the floor protected.
Related reading: Badminton Court Dimensions: Lines & Net Height — for the court geometry behind the markings.
A boundary line counts as in
A badminton boundary line is part of the area it marks, so a shuttle landing on the relevant line is in. That rule resolves the basic call; it does not by itself identify which overlapping gym marking belongs to the chosen badminton court. BWF Laws of Badminton
A boundary line is part of the area it marks, so a shuttle touching the line is in. On a shared gym floor, do not infer the badminton court from colour alone; trace the court geometry and ask the organiser if a marking remains unclear.
Singles and doubles use different service boundaries
Singles and doubles use different long service boundaries, so identify both the event and service situation before calling a serve long. The same painted gym court can therefore have a different relevant rear line without changing the rule that the line itself is in. BWF Laws of Badminton and BWF Shuttle Time Manual
| Format | Long service boundary | Line call |
|---|---|---|
| Singles | Back boundary | The relevant boundary line is in |
| Doubles | Rear doubles service line inside the back boundary | The relevant boundary line is in |
On a serve, singles uses the back boundary as its long service line; doubles uses the rear doubles service line inside it. In either format, the relevant boundary line is in. Agree the event and the server’s court before play so the group does not discover the difference after a close shuttle.
Make a shared gym-court reference
BWF specifies 40-millimetre, distinguishable court lines and prefers white or yellow; that helps a group recognize intended badminton markings among other gym lines. Before play, trace the agreed boundaries together rather than deciding an ambiguous mark only after a disputed rally. BWF Laws of Badminton
The cited Laws prefer distinguishable white or yellow 40-millimetre lines, but they do not establish a shared-gym colour system. If the court remains ambiguous, make a pre-serve local agreement or ask the organiser rather than guessing from a nearby basketball or volleyball line.
Use this distinction on court
Treat the floor-reading task as a short pre-serve orientation, not as an argument to settle after a close shuttle. Walk the court once from the net posts outward and name the badminton features that can be traced: the sidelines, the short service line, the centre service line, and the relevant back boundary. Then pause before play to identify whether the next service is singles or doubles. This sequence separates three questions that often get mixed together in a shared gym. First, which painted shape is the badminton court? Second, which boundary applies to this service situation? Third, once that boundary is known, did the shuttle touch its line? Only the third question is an in-or-out call. Colour can be a useful visual clue when it happens to be clear, but it should not become the group’s proof of court identity. A practical local habit is to agree on one neutral sentence before the first serve: “These are the lines we are using for this court and this format.” That sentence is a shared reference, not a replacement rule or a claim about every gym. If another sport’s paint crosses the court, return to the geometry rather than picking the outermost line. A player can point to the net-post sidelines and follow the service layout together with the other side before the rally begins. If the relevant boundary still cannot be identified, leave the decision with the organiser or facility instead of creating a confident but unsupported rule from a colour, width, or nearby marking. The value of the walkthrough is procedural: it lets everyone use the same court picture calmly before the score gives a close line call extra pressure.
Source-bound context
Before play on a multi-sport floor, make one short court-identification pass with the players who will serve first. Identify the badminton sidelines, the short service line, the centre service line, and the applicable long service boundary for the format being played. Then agree that a boundary line belongs to the area it marks. This is a practical way to reduce a preventable first-rally dispute; it is not permission to assume that the outermost painted line in every gym belongs to badminton.
Questions the cited sources do not settle
- A universal colour convention in every multi-sport gym.
- A claim that the outermost visible line always belongs to badminton without checking the court layout.
What to do next
Before the first serve in a multi-use gym, agree the badminton boundaries and the relevant long service line with the other players; ask the facility when the markings remain unclear.
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