A ball on the line is in; hindrance needs actual interference.

The ruleset used on this page

This page applies the ITF Rules of Tennis 2026, effective 1 January 2026, principally Rules 11–13, 23–26 and 28 with Appendix VII. For match procedure it uses the ITF Duties and Procedures for Officials 2026, which applies to ITF-sanctioned or recognised events.

The ITF is the global rule-making authority for tennis and now trades as World Tennis. A sanctioning body or tournament can appoint human line officials, Review Electronic Line Calling (Review ELC), Live Electronic Line Calling (Live ELC), clay-court inspection, or no chair umpire. Those procedures are not interchangeable, so this page names the applicable one at each variation.

Which line counts depends on the shot

Rule 12 says that a ball touching a line is regarded as touching the court bounded by that line. The relevant boundary is therefore:

• On serve: the lines of the diagonally opposite service court. A serve touching one of those lines is in, subject to the other service rules.
• In a singles rally: the singles sidelines and baselines.
• In a doubles rally: the doubles sidelines and baselines; the alleys are part of the court.

The whole ball does not have to land inside. If its contact with the surface reaches the relevant line, it is in; if it lands completely beyond that boundary, it is out.

First establish whether the ball was still in play

Under Rule 11, the ball is in play from the server's strike until the point is decided, unless a fault or let is called. Rule 24 then ends the point for events such as failing to return before a second bounce, returning the ball so that it lands outside the correct court, or touching the net while the ball remains in play.

This timing matters. A player cannot catch or hit a ball before it bounces and claim it was obviously going out: Rule 24, Case 8 says that player loses the point unless the contact itself produces a good return. Conversely, once an out ball has landed and been properly called, a later swing or return does not revive the rally.

A close call is not enough for an overrule

With line umpires, each line umpire calls the assigned line. The chair umpire calls any uncovered line and may overrule only a clear mistake, promptly after it occurs. The 2026 ITF procedure says the chair must be sure beyond reasonable doubt: to change “good” to “out”, the chair must have seen space between ball and line; to change “out” to “good”, the chair must have seen the ball land on or inside the line.

A player may ask the chair to verify a point-ending call, but a protest does not permit the chair or line umpire to change it. An overrule must come from the official's own clear and immediate determination.

“Out” corrected to “good” does not always replay the point

The ITF's 2026 officials' procedure treats the original call as a possible official hindrance:

• “Out” corrected to “good”: replay the point unless the chair decides the shot was a clear ace or clear winner that the opponent could not possibly have retrieved. If there is any reasonable possibility of a play, the opponent receives the benefit of the doubt and the point is replayed.
• “Good” corrected to “out”: the point ends; there is no hindrance remedy.

This is why “every corrected call is a let” is wrong. The direction of the correction and whether the first call could have affected a possible play control the result.

The route of appeal is different

Whether a particular ball landed in is a question of fact. In a chaired match, the on-court officials' determination is binding and cannot be appealed to the supervisor/referee. Whether the correct rule was applied to the facts is a question of tennis law; a player may ask for the ITF supervisor/referee, whose legal ruling is final.

Example: “That ball touched the line” is a factual dispute. “After the call was corrected, Rule 23 required a whole-point replay rather than only a first serve” is a rules-application question.

A challenge must be timely and must stop play

Where Review ELC is appointed, the 2026 ITF procedure allows review on a point-ending shot or when the player stops during the rally; a return is permitted, but the player must then stop immediately. A late or unreasonable request may be refused. If the system cannot decide, the original call or overrule stands, and the electronic result is not appealable.

The standard ITF allocation is three unsuccessful reviews per player or team per set, plus one additional review in a tie-break; successful reviews are unlimited. That allocation describes Review ELC, not every tennis match and not Live ELC.

Automatic line calling has no player challenge quota

Under the 2026 ITF Duties, Live ELC replaces line umpires and makes line calls automatically. Review ELC instead retains line umpires and lets players challenge. A viewer should first identify which system the event has appointed rather than assume every electronic call can be challenged.

If Live ELC fails, the ITF procedure requires the match to stop while the review official contacts the chair and supervisor/referee. The supervisor/referee decides whether to wait, move court, use available line umpires, postpone, or continue with the chair calling all lines. Tournament instructions can supplement those mechanics.

Ball-mark inspection is a separate procedure

ITF ball-mark inspections are available only on clay. The chair may inspect a mark on a point-ending shot or after a player stops promptly during a rally. If the correct mark cannot be found or is unreadable, the original call or overrule stands; deliberately erasing the mark before the decision concedes the call.

Review ELC on clay is different again. The Review Official section of the 2026 Duties specifies no ball-mark inspections and unlimited incorrect challenges for that setup. Event conditions therefore matter even when the surface is the same.

Players call their own side under the ITF notice

For an ITF event played without a chair umpire, each player calls all balls on that player's side of the net. “Out” and “fault” must be called promptly after the bounce and loudly enough to be heard; doubt goes to the opponent.

On a non-clay court, a player who corrects an incorrect “out” call normally replays the point, except that the caller loses the point if the shot was point-winning or that player had already made an incorrect “out” call in the match. On clay, correcting an “out” call to good costs the caller the point. These ITF tournament procedures should not be silently replaced with a club's or national association's local code.

Distraction alone does not decide the ruling

Rule 26 requires a player to be hindered in playing the point. The official should identify:

1. Was the point live? If it had already ended, Rule 26 cannot change the winner.
2. Was the opponent actually hindered? Irritation or noticing something is not automatically interference with play.
3. Who or what caused it? Opponent, outside source, the claimant, a pre-existing object, or a permanent fixture.
4. Was an opponent's act deliberate or unintentional? This selects point award or replay.
5. What procedure governs? The chair umpire calls “Hindrance” at a chaired ITF match; a player cannot simply award a personal let.

Deliberate action and intent to distract are not identical

If an opponent deliberately performs the act and it hinders the player, Rule 26 awards the point to the hindered player. A player who consciously shouts in celebration while the opponent is trying to hit the ball cannot avoid the ruling merely by saying the shout followed a mistaken belief that the shot was a winner. The official must still find actual hindrance.

For an involuntary player-created hindrance, such as a ball falling from a pocket or a hat falling off, the 2026 ITF procedure calls for a replay the first time the opponent is hindered and a warning that another such hindrance will be treated as deliberate and cost the point. A player cannot obtain a let for hindering only themself.

A stray ball can produce a let; crowd noise normally does not

A ball rolling or paper blowing onto court during play or during the service motion can be outside hindrance if it interferes with the player; the whole point is then replayed under Rules 23 and 26. The ITF rulebook's official case of a live ball hitting a bird also replays the point.

The 2026 ITF procedure expressly excludes crowd noise, a spectator's “out” call and similar distractions from hindrance: the point stands as played. Nor does Rule 26 apply to a permanent fixture. Rule 13 separately decides a ball's contact with a permanent fixture, and an object already lying on the player's side when the point began does not later become outside hindrance for that player.

Legal position can still become illegal hindrance

Rule 26, Case 5 permits the server's partner and receiver's partner to stand anywhere on their own side of the net, inside or outside the court. That freedom is not permission to distract an opponent deliberately. If the position or conduct creates a hindrance, the official applies Rule 26.

The decisive question is not simply “Was the partner standing inside the court?” but whether the partner performed an act that hindered an opponent and, if so, how that act is classified.

A line umpire corrects a return from out to good

Situation: a deep return is called out, then immediately corrected to good. The opponent had started toward the ball and might have reached it.

ITF 2026 ruling: replay the whole point. Under the officials' hindrance procedure, any reasonable possibility of a play prevents the hitter receiving the point as a clear winner.

A player celebrates before the reply

Situation: Player A hits near the line and deliberately shouts “come on” while Player B is making a playable swing. The ball was good.

ITF 2026 ruling: if the chair finds that the shout hindered Player B, Player B wins the point under Rule 26. Player A's mistaken belief that the rally was over does not make the act involuntary; if B was not hindered, play stands.

A second ball rolls behind the receiver

Situation: during a live rally, a ball from another court rolls behind the receiver and affects the receiver's attempt to play.

ITF 2026 ruling: outside hindrance; replay the whole point. If a first-service fault preceded the rally, Rule 23, Case 1 restores a first serve because the entire point—not just the interrupted rally stroke—is replayed.

An unchaired player is unsure about a baseline

Situation: in an ITF hard-court match without a chair umpire, the receiver sees a close bounce but cannot confidently call it out.

ITF 2026 ruling: the ball is treated as good and play continues. Appendix E requires the player responsible for that side to give the opponent the benefit of the doubt; an official who was not watching cannot reconstruct a different factual call merely from the later dispute.

How to decide a disputed point

1. Name the event and appointed procedure. Human officials, Review ELC, Live ELC, clay inspection, or no chair.
2. Find the first point-ending event. Out bounce, valid return, second bounce, touch, let, or hindrance.
3. Use the correct boundary. Service box, singles court, or doubles court.
4. If a call changed, apply the correction rule. Good-to-out and out-to-good have different outcomes.
5. If interference is claimed, require actual hindrance. Then classify the source and whether an opponent's act was deliberate.
6. Choose the remedy. Point to one side, whole-point replay, original call stands, or play continues.
7. Separate fact from law. Only a legal interpretation follows the supervisor/referee appeal route in a chaired ITF match.

Claims the 2026 rules do not support

• “Most of the ball was out, so it was out.” Contact with the relevant line makes it in.
• “Every distraction is a let.” The player must be hindered, and spectator noise is ordinarily excluded.
• “Accidental always means replay.” Self-hindrance gives no let, pre-existing objects do not qualify, and repeated similar player-created hindrance can cost the point.
• “Every correction replays the point.” Good-to-out ends the point; out-to-good can still award a clear ace or unreturnable winner.
• “The supervisor can reverse any line call.” A chaired match's factual call is binding; the supervisor/referee decides appealed questions of law.
• “Electronic calling always means challenges.” Review ELC and Live ELC are different systems.

Governing-body sources and effective versions

• International Tennis Federation — Rules of Tennis 2026: Rules 11–13, 23–26, 28; wheelchair rules; Appendix VII (effective 1 January 2026)
• International Tennis Federation — Duties and Procedures for Officials 2026: Articles I.E, II.C and II.P; Appendix E
• International Tennis Federation — 2026 Amendments to the Rules of Tennis and Beach Tennis

Checked against the ITF's current 2026 English rulebook, 2026 officiating procedures and published 2026 amendment notice on 28 August 2026. The amendment notice does not alter the line-touch or hindrance rules discussed here. ATP, WTA, Grand Slam, national-association and tournament regulations may supplement the baseline with their appointed calling, review and conduct procedures.