Last checked: August 2026 · Written by the player-led team at Badminton House
Under the main BWF service provisions, a badminton serve foot fault occurs when the server or receiver touches a service-court boundary, or fails to keep some part of both feet grounded and stationary from start to delivery. The current BWF Laws separately make undue delay, stop-start forward motion and a missed shuttle service faults.
Para-badminton scope: The specific provisions in Laws 9.1.3.1–9.1.4.2 cover half-court diagrams, wheelchair stationary-wheel requirements and medically justified exceptions.
Scope distinction: This guide covers feet, lines and timing. For the separate contact-height requirement, read the 1.15-metre badminton serve rule.
Quick answer: freeze the correct interval
Under the main foot-contact provision, check the shoes when the racket head first moves forward. From that frame until the racket hits or misses the shuttle, part of both feet must remain on the floor and both feet must stay stationary.
The feet-and-lines rule in plain language
Under the main standing-player provisions, the server and receiver begin in diagonally opposite service courts, and neither may touch a boundary line of that service court. Under BWF Laws 9.1.3 and 9.1.4, both players must then keep part of each foot grounded and the feet stationary through delivery.
| Check | Legal baseline | What the camera may reveal |
|---|---|---|
| Boundary lines | Both players stand inside their service courts without a shoe touching a boundary. | A front toe creeping onto the centre line or short service line. |
| Ground contact | Some part of both feet stays in contact with the court. | One shoe leaving the floor completely during the push. |
| Stationary position | Neither foot steps, slides or changes position from start to delivery. | A pivot, toe drag or heel lift that begins after the service starts. |
| Receiver | The same contact and stationary-position tests apply. | A split step beginning before delivery rather than after it. |
A line works differently for a shoe and the shuttle. A correctly served shuttle may land on its service-court boundary, but the server's and receiver's shoes may not touch their service-court boundaries before delivery.
A raised heel is not a separate flat-foot test. If a player begins with the heel raised, part of that foot can still be grounded. The video question is whether the grounded part remains in contact and whether the foot changes position after the service starts.
Know when the stationary-foot window begins
The foot rule does not run from the moment a player walks into the service court. Under BWF Laws 9.2 and 9.3, it runs from the racket head's first forward movement until the shuttle is hit or missed during the attempt.
Ready
Both players are in the correct courts, clear of the lines, and prepared for service.
Start
The first forward movement of the server's racket head starts the service and the stationary-foot window.
Delivery
The window ends when the racket hits the shuttle or the server misses it while attempting to serve.
This timing matters when reviewing a receiver who bounces or rocks. Judge the shoes rather than the torso: upper-body motion alone does not establish this foot fault. Look for a shoe sliding, stepping or losing all contact before delivery.
Undue delay and the stop-start hitch
Once server and receiver are ready, neither side may cause undue delay. The BWF service laws also define any delay after the racket head completes its backward movement as undue, then require the racket to continue forward from the start through delivery.
- Repeated setup adjustments: before both players are ready, a reset is not automatically the post-backswing fault. Once both are ready, repeated delay can still breach Law 9.1.1.
- Pause at the end of the backswing: completing the backward movement and waiting before beginning the forward action is the delay described in Law 9.1.2.
- Stop-start forward action: once the racket head first moves forward, stopping and launching a second forward movement breaks the continuous-forward requirement.
- Clean habit: settle the shuttle first, become ready, then use one unbroken action through contact.
On slow-motion video, mark the last frame of backward movement and the first frame of forward movement. A visible hold between them exposes the delay habit. Then follow the racket head to delivery; a second pause exposes the stop-start hitch.
Missing the shuttle still completes the attempt
A complete miss is not a practice swing followed by another serve. Under BWF Laws 9.1.8, 9.3 and 13.1, the server must not miss, the miss completes delivery, and an incorrect service is a fault.
That means there is no tennis-style second serve for an attempted miss. In practice and on video, record it as the end of that service attempt rather than resetting the shuttle and trying again.
Run a safe phone-camera self-check
A low rear view is best for the server's shoes and nearby lines; a side view makes the racket's backward and forward timing easier to see. Place the phone beyond the playing and run-off area, or ask someone to hold it. Never leave it where a player could step on it.
Review one serve frame by frame
- Confirm both shoes begin inside the correct service court and clear of every boundary.
- Mark the first forward movement of the racket head. This is the start frame.
- Track both shoes until contact or a miss. Look for a step, slide, pivot, new heel lift or complete loss of floor contact.
- Mark the end of the backswing. Check for a pause before the forward movement begins.
- Follow the forward action to delivery. Check for a stop and restart.
- When reviewing a receiver, apply the same shoe test and ignore torso motion unless it moves the feet.
A self-officiated game may have nobody assigned to watch these details. In a match with an appointed service judge, the current BWF Instructions to Technical Officials, Version 8.0 (2) make that judge responsible for the listed service laws, with a “Fault” call and hand signal; the umpire then explains the specific infringement.
The useful response is to build the same repeatable setup everywhere: shoes clear of the lines, feet settled, shuttle adjusted before the backswing, and one continuous forward action. Then an official match does not ask for a different serve from the one you practise.
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