Rules the serve
What Is a Foot Fault in Tennis? The Rule, the Penalty and Double Faults
A foot fault is a serve that breaks the rule on where the server's feet may be: on the baseline, inside the court, or past the centre mark or sideline before the ball is hit. It costs the serve, and a second fault costs the point.
- Rule 18
- 4things the feet may not do
- Serves per point
- 2two faults lose the point
- Extra penalty
- 0a foot fault only costs the serve
Photo: Carine06 from UK, CC BY-SA 2.0, cropped, via Wikimedia Commons
The rule
The foot fault rule in tennis
In shortRule 18 of the ITF Rules of Tennis says that during the serve the server may not walk or run, touch the baseline or the court with either foot, or touch the area outside the extensions of the sideline or the centre mark.
- Rule 18(b) No foot may touch the baseline or the court inside it until the ball is hit.
- Rule 18(c) No foot outside the imaginary extension of the sideline: the singles sideline in singles, the doubles sideline in doubles.
- Rule 18(d) No foot on the imaginary extension of the centre mark.
- Rule 18(a) No walking or running into the serve; slight movements of the feet are allowed.
Paraphrased from Rule 18 of the ITF Rules of Tennis. Drawn to scale: singles court 8.23 m wide, doubles 10.97 m.
The foot fault rule exists to keep the serve fair. The server already has the biggest advantage in tennis; letting them creep a step into the court, or run into the ball like a bowler in cricket, would make it bigger. So the rule fixes where the serve is hit from. Rule 16 places the server at rest behind the baseline, between the imaginary extensions of the centre mark and the sideline, and Rule 18 lists the four ways to break that.
The key word is "touch". Until the racket hits the ball, neither foot may touch the baseline itself, any part of the court inside it, the ground beyond the sideline's extension or the extension of the centre mark. A foot in the air above the line is fine. That is why the jumping serve of almost every professional is legal: the player takes off from behind the line and lands in the court after the ball has gone.
The sideline that counts depends on the match. In singles it is the singles sideline, so standing in the alley to serve is a foot fault; in doubles it is the doubles sideline, and standing wide in the alley is a common tactic. Slight movements of the feet during the motion are allowed. A step forward that changes the server's position is not.
Penalty
What is the penalty for a foot fault?
In shortA foot fault is treated as a fault. The serve does not count, so on a first serve the server gets a second, and on a second serve it is a double fault and the point goes to the receiver.
| Serve | First serve | Second serve |
|---|---|---|
| Foot fault | Fault, second serve | Double fault, point lost |
| Into the net or out | Fault, second serve | Double fault, point lost |
| Clips the net, lands in | Let, first serve again | Let, second serve again |
| Lands in the box | Ball in play | Ball in play |
There is no extra penalty on top of the lost serve. A foot fault is a rule infringement, not misconduct, so it does not go on the code violation ladder and carries no fine. The same server can foot-fault ten times in a match and the only cost is the ten serves. The foot fault penalty is real enough, though. A fault called on a second serve at 30-40 loses the game.
What does get punished is the reaction. At the 2009 US Open semifinal, Serena Williams was serving to stay in the match against Kim Clijsters, at 5-6 in the second set, when a line judge called a foot fault on her second serve. The double fault gave Clijsters match point. Williams's outburst at the line judge brought a point penalty, and because it came on match point it ended the match, 6-4, 7-5. She was fined $10,000 on site and later a record $82,500 by the Grand Slam committee, with probation. The code violation guide explains how that ladder works.
Double faults
Foot faults and the double fault
In shortA double fault is two faults on the same point. The kind of fault makes no difference. A foot fault on the first serve followed by a second serve into the net is a double fault, and the server loses the point.
Under Rule 24 of the ITF rules a player loses the point if they serve two consecutive faults. That is the double fault, and it is one of the few ways in tennis to lose a point without the opponent touching the ball. The two faults can be any combination: long, wide, into the net, a miss of the ball entirely, or a foot fault.
A let does not break the sequence. If the first serve is a fault and the second clips the net and lands in, the server takes the second serve again; a let on the second serve is still a second serve. And because the server's score is called first, a double fault at 30-40 is the one result every server dreads. The tours count double faults in every match's statistics, next to aces, because the two often come from the same risk: a second serve hit to win the point rather than just to start it.
For club players the double fault is usually the bigger problem than the foot fault. A second serve hit with less pace and more spin is the standard fix; the foot position is fixed separately, by drilling the stance until it holds even under pressure.
Rule check
Foot fault or legal? A quick rule check
In shortSix serving situations. Pick an answer for each and the explanation follows; every answer comes straight from Rule 18.
Foot fault rule check
Who calls it
Who calls a foot fault in tennis?
In shortAt officiated matches a line judge watching the baseline or the chair umpire calls it. Where cameras have replaced line judges, the electronic system makes the call. In club matches without officials it is rarely called.
For most of the sport's history the call belonged to the line judge sitting at the end of the baseline, who watches the server's feet before switching to the ball. The chair umpire can call an obvious one too. That changed at the top level when electronic line calling took over. Wimbledon replaced its line judges with an electronic system from the 2025 Championships, and the ATP did the same at its tour events in the same year.
In unofficiated matches the rule still applies, but the USTA's code for club play makes the receiver's call a last resort, meant only for clear, flagrant foot faults that persist after a word with the server. That is why most recreational players never hear the call, and why many first hear it in their first league or tournament match, from an official they did not notice was watching. The full set of serving rules is on the tennis rules page.
Avoid it
How to avoid foot faults
In shortMost foot faults come from an inconsistent ball toss that pulls the server forward. Fix the toss, start with the front foot a few inches behind the line, and keep the back foot from sliding over the centre mark.
Coaches and officials tend to agree that the feet are usually a symptom. A toss that drifts forward makes the server chase it, and the front foot creeps onto the line. Practise the toss on its own, letting the ball drop to see where it lands; it should fall just inside the baseline, in front of the front foot, every time.
Two habits help with the rest. Mark your stance a few inches behind the baseline and start every serve from there, so there is room for the foot to move. And watch the back foot on a pinpoint stance, where it slides up to meet the front one: it can drift past the centre mark extension in the deuce court without the server noticing.
One more thing worth knowing if you play doubles is that the alley is legal ground behind the baseline. Standing wide opens up the angle, and nobody can foot-fault you for it.
FAQ
Foot faults in tennis: questions and answers
In shortQuick answers on the foot fault rule, the penalty and double faults.
What is a foot fault in tennis?
A foot fault is a serve where the server's foot touches the baseline or the court inside it, or the area beyond the imaginary extension of the centre mark or the sideline, before the racket hits the ball. Walking or running into the serve is also a foot fault.
What is the penalty for a foot fault in tennis?
The serve counts as a fault, exactly as if it had gone into the net. If it happens on a first serve, the server gets a second serve; on a second serve it is a double fault and the receiver wins the point.
Do they still call foot faults in tennis?
Yes, at every level with officials. At professional events they are called by line judges or the chair umpire, and at events with electronic line calling the system can make the call. In club matches without officials they are rarely called.
Can you jump over the baseline when serving?
Yes. The rule only forbids touching the baseline or the court before the ball is struck. Most professionals take off from behind the line and land inside the court after hitting the ball, which is legal.
What is a double fault in tennis?
A double fault is two faults in a row on the same point, for example a first serve into the net and a second serve that lands long. The server loses the point. A foot fault on either serve counts as one of the two faults.
Can the receiver call a foot fault?
In matches without officials, the USTA's code for unofficiated play lets the receiver call a foot fault only in clear and flagrant cases, after trying other ways to resolve it. In officiated matches only the officials can call it.
Is a foot fault a code violation?
No. A foot fault is a rule infringement that decides a serve, not a conduct offense. Arguing about it can become one. Serena Williams's outburst after a foot fault call at the 2009 US Open led to a point penalty.
Can you stand anywhere behind the baseline to serve?
Only between the imaginary extension of the centre mark and the imaginary extension of the sideline: the singles sideline in singles and the doubles sideline in doubles. How far back you stand is up to you.