Tennis serving rules.

The serve is the only shot in tennis where you have complete control. No opponent has touched the ball, no rally is underway, and you decide the pace, spin, placement, and timing entirely on your own terms. It is the one shot that sets up everything that follows, and at the professional level it is often the single biggest weapon in a player's arsenal.

Every point in tennis begins with a serve. The server stands behind the baseline on one side of the court, tosses the ball into the air, and strikes it over the net into the diagonally opposite service box. If the serve lands legally, the rally begins. If it does not, it is a fault, and the server gets a second chance. Two faults in a row — a double fault — and the point goes to the receiver.

The serving rules in tennis are designed to balance the server's natural advantage. The requirement to land the ball in a relatively small box on a diagonal, the two-serve system, the foot fault rules, and the alternating service sides all work together to keep the serve powerful but not unreturnable. Understanding these rules is fundamental to playing tennis at any level, from a public park to Centre Court.

The server must stand behind the baseline, between the imaginary extensions of the centre mark and the relevant sideline. On the first point of every game, the server stands to the right of the centre mark (the deuce side) and serves diagonally into the opponent's deuce-side service box. On the second point, the server moves to the left of the centre mark (the ad side) and serves into the opponent's ad-side service box. This alternation continues for every point in the game.

• — The server must not touch the baseline or the court inside the baseline with either foot before striking the ball. This is the most basic foot fault.
• — The server must not step outside the imaginary extension of the centre mark toward the net. Moving too far toward the centre of the court before contact is a foot fault.
• — The server must not step outside the imaginary extension of the sideline. For singles, this is the singles sideline; for doubles, the doubles sideline.
• — At least one foot must be in contact with the ground at the moment the ball is struck. Jump serves are legal in tennis — both feet can leave the ground during the toss and swing — but the jumping motion must start from behind the baseline and the server must not land inside the court before striking the ball.

The deuce court and ad court naming convention is worth memorising. The deuce court is the right side when facing the net — named because at deuce (40-40) the point is always served from this side. The ad court is the left side — named because at advantage the serve comes from here. Every odd-numbered point in a game is served from the ad court, every even-numbered point (including the first) from the deuce court.

The rules governing the actual serve motion in tennis are surprisingly permissive. The server must toss the ball into the air with the non-racket hand and strike it with the racket before the ball hits the ground. That is nearly the entire rule. There is no requirement for an overhand motion, no minimum toss height, and no restriction on grip or racket angle.

• — The ball must be tossed — released from the non-racket hand — before being struck. You cannot hit the ball directly out of your hand.
• — The ball must be struck before it bounces. If you let the toss drop without swinging, you may catch it and re-toss without penalty. But once you swing, the serve counts.
• — Any grip or stroke is legal. Overhand is standard because it generates the most power and spin, but underhand serves are completely legal and have been used in professional matches.
• — The ball must travel over the net (it may touch the net — see let serves below) and land in the diagonally opposite service box.

Most competitive players use one of three serve types: the flat serve (maximum pace, minimal spin), the slice serve (sidespin that curves the ball away from the receiver), and the kick serve (heavy topspin that bounces high). The first serve is typically hit with more pace and risk, while the second serve prioritises spin and placement to reduce the chance of a double fault. Understanding the two-serve system is essential to tennis serve strategy.

If the toss is poor, the server may let the ball drop and re-toss. The umpire may warn a player who abuses this rule with excessive delays, but in practice a single catch and re-toss is routine. The key is that you must not swing at the ball — once the racket moves toward the ball with intent to strike, the serve is in play.

Tennis gives the server two attempts to put the ball into play on every point. This is one of the defining features of the sport and shapes nearly all serving strategy.

• — The first serve can be hit with maximum aggression. If it faults — hits the net, lands outside the service box, or commits a foot fault — the server gets a second attempt.
• — The second serve must land legally or the server loses the point. A fault on the second serve is a double fault, and the receiver wins the point outright.
• — There is no third serve under any circumstances. Two attempts per point is the absolute maximum in all formats of tennis — singles, doubles, juniors, and all Grand Slams.
• — A let on the first serve gives you another first serve. A let on the second serve gives you another second serve. Lets do not consume one of your two attempts.

This two-serve system creates a natural tension. The first serve is a chance to take a risk — hit a big flat serve down the T, or a wide slice that pulls the opponent off the court. If it misses, you still have a safety net. The second serve is where the pressure shifts. Miss this one and you hand the opponent a free point. Most players add significantly more spin to their second serve to increase the margin for error over the net and ensure the ball dips into the service box.

At the professional level, first-serve percentages typically hover between 55% and 70%. Second-serve percentages are much higher — often above 85% — because players consciously reduce pace in favour of consistency. The double fault rate for most tour players sits between 2% and 5% of service points, but it spikes under pressure, making second-serve reliability one of the most important skills in tennis.

A foot fault is one of the most common serving violations in tennis, and it is called more often than most recreational players realise. The rule is straightforward: before the ball is struck, the server's feet must remain behind the baseline and within the legal serving zone.

• — Touching the baseline with either foot before striking the ball is a foot fault. Even brushing the line with a toe counts.
• — Stepping onto the court (inside the baseline) before contact is a foot fault. The server may step on or over the baseline after the ball has been struck — the restriction applies only up to the moment of contact.
• — Moving outside the imaginary extension of the centre mark toward the net is a foot fault. This prevents servers from creeping toward the centre of the court for a better angle.
• — Moving outside the imaginary extension of the sideline is a foot fault. In singles, the relevant line is the singles sideline. In doubles, it is the doubles sideline.

A foot fault counts as a fault on that serve. If it occurs on the first serve, the server gets a second serve. If it occurs on the second serve, it is a double fault and the receiver wins the point. In professional tennis, a line judge or electronic system monitors foot faults, and they are called strictly. In recreational play, foot faults are often ignored or self-policed, but understanding the rule is important for competitive play and good habits.

The most common foot fault in recreational tennis is the server's front foot sliding onto the baseline during the forward motion of the serve. The simplest fix is to set up a few inches further behind the baseline and focus on keeping the front foot planted until after contact.

A let serve occurs when the ball clips the top of the net cord and still lands in the correct diagonal service box. When this happens, the serve is replayed with no penalty whatsoever.

• — If a first serve is a let, the server gets another first serve.
• — If a second serve is a let, the server gets another second serve.
• — There is no limit to the number of consecutive lets. If the ball clips the net and lands in the service box five times in a row, all five are replayed.
• — If the ball clips the net but lands outside the correct service box or in the wrong box entirely, it is simply a fault — not a let.
• — If the ball clips the net and does not clear it at all, it is also a fault.

The let serve rule exists because the net cord introduces an element of pure luck that would be unfair to penalise. A ball that catches the net tape slows down dramatically and can change direction unpredictably, making it nearly impossible for the receiver to prepare. By replaying the serve, the rules ensure that the point begins fairly.

This is one area where tennis differs from pickleball, which abolished the let serve in 2021. In tennis, the let remains — and at the professional level, the net cord sensor (or the umpire's judgement) determines whether the ball touched the net. In recreational play, the honour system applies: if you hear or feel the ball clip the net, call the let.

The service box in tennis is a precisely defined rectangle. Understanding its dimensions helps you visualise targets and understand why certain serve placements are so effective.

• — Each service box is 21 feet (6.40 metres) deep, measured from the net to the service line.
• — Each service box is 13.5 feet (4.115 metres) wide in singles, measured from the centre service line to the singles sideline.
• — In doubles, the service box width remains 13.5 feet — the serve must still land between the centre service line and the singles sideline. The doubles alleys are not part of the service box.
• — The total service area on each side of the net is 21 feet deep by 27 feet wide (the full singles court width), divided into two equal boxes by the centre service line.

For context, the full tennis court is 78 feet long (39 feet per side) and 27 feet wide for singles or 36 feet wide for doubles. The service line sits exactly halfway between the net and the baseline on each side. This means you are aiming at a target that is roughly 21 by 13.5 feet — about the size of a large living room — from behind a baseline that is 39 feet away from the net.

The three most common serve targets are the "T" (where the centre service line meets the service line, pulling the receiver into the middle of the court), the "wide" serve (targeting the outer edge of the service box near the singles sideline, dragging the receiver off the court), and the "body" serve (aimed directly at the receiver's hip to jam their return). All three are made possible by the geometry of the service box.

The serving rules in doubles tennis are identical to singles in terms of motion, foot faults, lets, and the two-serve system. The differences are in who serves, when, and where players are allowed to stand.

• — The serve must still land in the diagonally opposite service box. The doubles alleys are not part of the service box — the target is the same size as in singles.
• — The server alternates every game, rotating through all four players in a fixed order. If the order is A1, B1, A2, B2, then A1 serves game 1, B1 serves game 2, A2 serves game 3, B2 serves game 4, and the cycle repeats.
• — The serving order is set at the start of each set. Each team chooses which player serves first for their team, and the alternation follows from there. Teams can change their serving order at the start of a new set.
• — The server's partner can stand anywhere on the court during the serve — at the net, at the baseline, on the same side as the server, or on the opposite side. There is no restriction on the server's partner's position.
• — The receiving team designates which player receives from the deuce court and which receives from the ad court. This choice is fixed for the entire set. The receiver's partner typically stands at the net but can stand anywhere.

A common doubles strategy is the "I-formation," where the server's partner crouches at the centre of the net and moves to one side or the other after the serve is struck, depending on a pre-arranged signal. This is legal because the rules place no restrictions on where the non-serving players stand — only on where the server stands and where the ball must land.

The serving rotation ensures that all four players share the serving load equally over the course of a set. If your team has one strong server and one weaker server, the rotation forces you to hold serve with both, not just the stronger one. This is a deliberate design choice that prevents teams from hiding a weak server.

A quick-reference checklist. Any of these will count as a fault on the current serve — first-serve fault gives you a second serve, second-serve fault gives the opponent the point.

• — Foot fault: foot touching or crossing the baseline before contact.
• — Foot fault: foot outside the imaginary extension of the centre mark or sideline.
• — The ball hits the net and fails to cross to the opponent's side.
• — The ball lands outside the correct diagonal service box (long, wide, or wrong box).
• — The ball bounces before the server strikes it (the toss must be hit in the air).
• — The server swings and misses the ball entirely (a "whiff" counts as a fault).
• — The server serves from the wrong side of the court (deuce instead of ad, or vice versa).
• — Time violation: the server takes longer than the allowed time between points (25 seconds on the ATP/WTA tour).
• — The server tosses two balls simultaneously.
• — The ball hits the server's partner or clothing before crossing the net in doubles.

In professional tennis, electronic line-calling systems (like Hawk-Eye Live) have made line calls more accurate than ever. In recreational play, you call your own lines. The spirit of the rule is simple: if you are not sure whether the ball was in or out, it is in. The same principle applies to foot faults — if you are not sure whether your foot touched the line, give yourself the benefit of the doubt, but also adjust your position for the next serve.