What is a fault in tennis? All Types of Faults and Tips to Fix Them

In tennis, a fault occurs when the serving player is unsuccessful in hitting the ball into the proper service court. Many things can cause a fault including hitting the ball out of bounds, hitting the ball in the net, and incorrect foot movement. In this article, we will look at these scenarios in more detail to further answer the question, “what is a fault in tennis?”

what is a fault in tennis - tennis player serving

There are two main types of fault in tennis. The first is a “service fault” and the second is a “foot fault”. Violating either of these results in a fault. During a player’s service, they are allowed two opportunities to successfully serve into the service box of the opponent’s court. The “first serve” and “second serve”. If the player fails to correctly serve on either opportunities, it is a “double fault” and they lose the point.

Types of Fault In Tennis

Let’s look at the two types of fault in tennis.

Service Fault

The service is a fault if:

  1. The ball does not land within the boundary of the proper service court. Many players refer to this as the service square or service box. The server must hit the ball into the service court that is located diagonally or “cross court”. The ball may touch any of the lines in the service box. However, if the first bounce is outside the service box or its lines, it is considered a fault.
  2. The server swings at the ball but misses it. However, if the server tosses the ball and catches it or lets it hit the ground and does not swing at it, this is not a fault. 
  3. The ball served touches a permanent fixture, singles stick, or net post before it hits the ground. For example, if the ball served hits the net post and then lands in the correct service square, this is still a fault. 
  4. The ball served touches the server or server’s partner, or anything the server or server’s partner is wearing or carrying. In a doubles tennis match, the server may accidentally strike their partner, or anything attached to them when serving the tennis ball. This is considered a fault.
  5. The ball lands in the net. Probably the most obvious fault in tennis is when a player serves the ball and it lands in the net.

Foot Fault

A foot fault occurs when any of the following occur during the service motion:

  1. The server touches the baseline or the court with either foot. The server is allowed to touch the baseline or the court after the ball is hit.  
  2. The server changes position by either walking or running. Although, slight movements of the feet are permitted, rapid adjustments in the server’s position is considered a foot fault.
  3. Either foot touches the imaginary extension of the center mark. The server must stand to the side of the center mark and neither foot is allowed to touch it.
  4. Either foot touches the area outside the imaginary sideline extension. For example, in singles the server cannot stand in the area behind the doubles alley (the space between the singles line and the doubles line).
A tennis player committing a foot fault

What happens when a fault occurs?

What happens when a fault occurs depends on if it is the first or second serve. Players are allowed two serves for each point. When a fault occurs on the first serve, the serving player has one more opportunity to serve. If the fault occurs on the second serve, the serving player loses the point and the term for this is a “Double Fault”.

Is a let a fault?

A “let” is not a fault. This occurs when a serve hits the net, but still manages to land in the proper service court. When this happens, the server is allowed to re-take the serve. However, if the ball lands in the wrong service court after hitting the net, this is a fault. There are no limitations on the number of “lets” that can occur in a game or a set.

Where did the term “Fault” originate?

The term “fault” in tennis originates from the Old French word “faute,” which means a mistake or error. This terminology is used specifically in tennis to indicate a specific type of mistake made during the serve or, less commonly, during play. The reason “fault” is used instead of “out” is due to the distinct rules and contexts in which these terms apply in tennis.

  • “Fault” specifically refers to an error during the service. It occurs when the serve fails to land in the correct box (the services box), the server steps on the baseline before hitting the ball, or the ball hits the net and lands out of bounds. It indicates a failed first attempt at a serve, giving the server a second chance.
  • “Out,” on the other hand, indicates that the ball has landed outside the designated play area on the court during a rally. This term signifies that a point is lost due to the ball not landing within the boundaries of the court.

The differentiation in terminology helps in clearly communicating the nature of the error and the consequent rule application in the game.

What Causes a Fault and How to Avoid It

Let’s first look at what some of the causes of a SERVICE FAULT and how to prevent them. 

Poor Serving Accuracy

The most obvious answer is to improve your serving accuracy. There are several things that cause inconsistent serves. Probably the most common is hitting a flat serve.  If you hit a serve with moderate to fast pace, the chance of hitting a flat serve in the proper service court is slim. It generally will either hit the net or go out.  Hitting a slice or spin serve is a much more consistent serve. The spin allows you to hit up on the ball to get it over the net and the spin will bring it down into the service court.

Improper or Inconsistent Toss

Another cause of faults is an improper or inconsistent toss. If the ball toss is too far behind you then it will go past the service court. If the ball toss is too far in front of you then it will go into the net.

A tennis player hitting a serve too hard and causing a fault or double fault

Hitting Too Hard

A very common error by intermediate level players is simply trying to hit the ball too hard. Some players will try to “blast” their first serve and then after missing it will “dink” their second serve in. A better approach is to hit a moderately paced 1st and 2nd serve with spin.

Environmental Factors

There are also some environmental factors that can wreak havoc with our serves, such as the wind and sun. 

  1. Wind. Winds of 15 to 20 mph are not uncommon and it can really blow your toss around, making it difficult to hit a good serve. I played in a USTA League match recently and we had wind gusts of 25 to 27 mph. That made serving and just hitting the ball over the net (when hitting against the wind) very difficult.

    Wind can actually sometimes play in your favor however, particularly if you are playing doubles. Sometimes one player may prefer to hit “into the wind” while his or her partner may prefer to hit “with the wind”.  For example, if a player has a relatively slow serve but with a ton of spin, hitting with the wind can be an advantage, giving the ball a bit more speed. Another consideration is your ball toss.

    If you have a very high ball toss, you can experiment with increasing your service swing speed and lowering your toss slightly. Players with a very fast service motion can get away with tossing the ball somewhat lower. Some players can even hit the ball toss “on the rise” as it is still going up rather than hitting the ball on the decline after it has reached its peak. There was a player in the 1970’s by the name of Roscoe Tanner and he hit the ball as it was still going up. 
  2. The sun. Looking into the sun can be devastating for a server’s consistency. There are no easy answers for dealing with the sun but a few options might help. When I am serving into the sun or playing in the sun I always wear sunglasses. I wear prescription “progressive” glasses and had a pair of sunglasses made with my prescription.

    A good quality pair of sunglasses can also benefit by protecting your eyes from UV light. The next item I recommend wearing is a lightweight cap or flap cap. A flap cap has protection on the sides and back of your neck and helps to reduce the sun glare. The third thing that is often easier to say than do, is to adjust your toss either left or right a bit to move it away from the sun.

Next let’s look at some causes of FOOT FAULTS and how to prevent them.

  1. Moving the front foot. The most common cause of a foot fault is moving your left foot (if you are right handed). If you stand very close to the baseline and move this foot slightly, you likely will touch the line before hitting the serve. Practice serving the ball and not moving the front foot at all. Also, I recommend that you stand 2 to 3 inches behind the baseline – if you move your front foot slightly, then you will not commit a foot fault. 
  2. Moving the back foot. Some people move their right foot around while serving. While a small movement of the back foot can be acceptable, you do not want to move the back foot around your body.  This opens up your shoulders too quickly and can cause inconsistency in your serves and risk foot faulting. 

What can you do if you are consistently missing the first serve?

If your percentage of first serves going in are low, then you are most likely trying to hit it too hard. We should all try and obtain a 70% “first serve in” ratio. Why such a high number? The reason is because consistently missing your first serve and relying on your second serve takes the pressure off of your opponent and puts it on you.

How many times have we all been serving with a score of 30-40 and have missed our first serve? This situation certainly puts the pressure on us doesn’t it? In fact, if you are receiving and your opponent misses his first serve, you have essentially been given a “gift”. This is because in most cases the second serve is slower (and therefore easier to return) than the first serve. And continuing that logic, if you are the server and have “double faulted”, you have given your opponent a big gift: a free point! Who doesn’t like free stuff? 

What should I do if I miss my first serve?

Missing a first serve is not the ideal situation as just discussed. However, no one hits 100% of their first serves in, so what do I do? The first thing is do not panic! One method most athletes use is a simple relaxing technique of inhaling through your nose and exhaling out through your mouth. Do this two or three times and just let your shoulders relax.

Another common effect of pressure is we tend to grip the racket too tight. If you do this, the muscles in your hand, wrist and arm tighten up. This tenseness is exactly what we are trying to avoid. Some people hop from foot to foot just to relieve some of the tension. Even professional tennis players double fault so if it happens, don’t stress over it. The most important thing is not to freak out. Tell yourself “I’ve got this,” do some relaxing techniques, and be confident.

2 thoughts on “What is a fault in tennis? All Types of Faults and Tips to Fix Them”

  1. Dan,

    I was searching for why an out serve is called a “fault” and Google brought up your page. Do you know the origin of why they say “fault” and not just “out?”

    Many thanks,


    1. A fault as used in the English language has many definitions but is generally thought of as having a flaw or defect or weakness. In the game of tennis it is a broad term describing an error or more specifically something illegal. For example, if you miss the service court while serving it is a fault. The ball may have been hit into the net, or hit long, or hit wide. If the server steps on or over the baseline before the ball is struck – it is a fault. During a rally it is illegal to hit the ball twice to get it over the net. This could also be described as a fault- it is not legal. Fault was derived from the old French word “faute”, which means fault or mistake. I hope this helps. Dan

Leave a Comment

Your email address will not be published. Required fields are marked *

Notify me of followup comments via e-mail. You can also subscribe without commenting.