World Snooker Championship Format: Rounds and Sessions
The World Snooker Championship format explained: 32 players at the Crucible in Sheffield, five rounds over 17 days and a best-of-35 final in four sessions.
By CricketTaken EditorialPublished World Championship & the Tour25 min read
- Players at the Crucible
- 32
- Rounds
- 5
- Final
- Best of 35 frames
- Frames needed to win the title
- 71
At ten o'clock on the first Saturday morning the defending champion walks down the steps at the Crucible Theatre in Sheffield to play the opening match. Seventeen days later, on the early May bank holiday Monday, somebody lifts the trophy. Whoever it is has won 71 frames to get there.
That number is the format in miniature. The World Snooker Championship is a straight knockout for 32 players over five rounds, run by World Snooker Tour under the WPBSA's rules, and the matches lengthen as the field shrinks: best of 19 frames in the first round, best of 25 in the second round and the quarter-finals, best of 33 in the semi-finals and best of 35 in the final. Ten, thirteen, thirteen, seventeen and eighteen frames to win. Every match is broken into sessions, two for the first round, three for the next two rounds and four for the semi-finals and final, and the final's four sessions fall across the last Sunday and Monday.
Five rounds from best of 19 to best of 35
No other tournament on the professional calendar asks this much. A first-round match at the Crucible is already as long as, or longer than, the final of most ranking events, and it is the shortest thing a player will be asked to do all fortnight.
| Round | Players left | Match length | Frames to win | Sessions |
|---|---|---|---|---|
| First round | 32 | Best of 19 | 10 | 2 |
| Second round | 16 | Best of 25 | 13 | 3 |
| Quarter-finals | 8 | Best of 25 | 13 | 3 |
| Semi-finals | 4 | Best of 33 | 17 | 4 |
| Final | 2 | Best of 35 | 18 | 4 |
Two details in that table are easy to miss. The quarter-final is no longer than the second round, so the step up after round one is followed by a plateau. And the final is only two frames longer than a semi-final, which is why players who have come through a 17-16 semi on the Saturday night sometimes look more drained on the Sunday than the format on paper would suggest.
A champion who never drops a frame plays exactly 71. A champion taken to a deciding frame in every round plays 137, close to double. The real figure always sits somewhere between, and where it sits says a good deal about how the title was won: a player who has been at the table for 120 frames has had a different fortnight from one who has been there for 95.
Across the whole event there are 31 matches. If every one finished in the minimum number of frames the tournament would run to 368 frames, and if every one went to a decider it would run to 705. Those are arithmetic limits, not records, but they show the scale of what is being fitted into one theatre in a little over a fortnight.
Scores at this distance read differently too. A 10-9 or a 13-12 means a match settled on the last possible frame. A 13-3 means a contest that ended a full session early. How match lengths vary across the rest of the tour is set out in our guide to how many frames a snooker match has; this page stays with Sheffield.
What a session is and why a match stops halfway
Snooker at this length cannot be played in one sitting. A best-of-25 match can take eight or nine hours of table time, and a best-of-35 final considerably more. So each match is cut into sessions: fixed blocks of frames, scheduled for a set start time, after which the players stop wherever the score happens to stand and come back later.
At the Crucible the long-standing pattern is three sessions a day, starting in the morning, the mid-afternoon and the evening. For many years those have been 10am, 2.30pm and 7pm, with the final using an earlier afternoon start. The tour sets the timetable for each championship and the times can shift, so treat those as the customary pattern and check the order of play for the year in question.
A session has two defining features. It contains a predetermined number of frames, usually eight. And it does not care about the score. A player leading 7-1 stops at the end of the eighth frame exactly as a player trailing 1-7 does, and both go back to the hotel.
The mid-session interval
After the fourth frame of a session the players leave the arena for an interval of about fifteen minutes. It exists for practical reasons: the table is brushed and the balls cleaned, the audience can move, and television gets a break. Its effect on matches is larger than its length. A player who has lost the first four frames has a quarter of an hour to reset, and it is a commonplace of Crucible commentary that the frame straight after the interval is where a session turns.
In the longer closing sessions, which can hold nine or ten frames, the interval still comes after the fourth. That leaves a long second half, sometimes five or six frames without a pause.
Sleeping on a lead
The gap between sessions is the format's most distinctive feature. A first-round match might start on a Tuesday morning and resume that evening, or not until the following afternoon. A semi-final is spread across three days. The score is carried over the break, reported as "5-4 after the first session" or "10-6 overnight", and the players have hours to think about it.
That thinking time is not neutral. A big overnight lead is uncomfortable to hold, because there is nothing to do with it except not lose it. A deficit can look smaller after a night's sleep. Short-format snooker rewards the player who starts fast. The Crucible rewards the one who can come back to the same match three or four times and find his game again each time.
How the frames are divided between sessions
The allocation is fixed in advance for every round and it is not symmetrical.
| Round | Session one | Session two | Session three | Session four |
|---|---|---|---|---|
| First round, best of 19 | 9 frames | Up to 10 | Not played | Not played |
| Second round, best of 25 | 8 frames | 8 frames | Up to 9 | Not played |
| Quarter-final, best of 25 | 8 frames | 8 frames | Up to 9 | Not played |
| Semi-final, best of 33 | 8 frames | 8 frames | 8 frames | Up to 9 |
| Final, best of 35 | 8 frames | 9 frames | 8 frames | Up to 10 |
That is the split in use now. It has been adjusted over the years: the 1985 final, for one, played seven frames in its first session and nine in its second, sixteen on the opening day where today there are seventeen.
Every session except the last plays its full allocation. The last runs until somebody reaches the target and then stops; snooker does not play dead frames, so a first-round match won 10-4 ends after fourteen and the remaining five are never played.
When a match can and cannot end early
The arithmetic produces some firm rules. A first-round match cannot be won in its opening session, because nine frames are played and ten are needed. A best-of-25 cannot be won in its first session either. But it can be won in the second: sixteen frames are scheduled across the first two sessions, so a player who reaches 13 with three or fewer against him finishes the job there and then, and the third session is never needed. The phrase for this is winning "with a session to spare".
The same holds further up. Twenty-four frames are scheduled across the first three sessions of a semi-final, so a scoreline of 17-7 or better ends it a session early. Ronnie O'Sullivan's 17-4 win over Stephen Hendry in 2004 did that, and so did Zhao Xintong's 17-7 defeat of O'Sullivan in 2025, which finished on the last frame of the third session.
In the final, 25 frames are scheduled before the last session, and a player who gets to 18 inside them has won with the Monday evening unused. Steve Davis beat John Parrott 18-3 in 1989, which was still the most one-sided final staged at the Crucible after the 2026 championship. Stephen Hendry beat Jimmy White 18-5 in 1993. Both were over on the Monday afternoon.
The final cannot be won on the Sunday
One consequence of the split is worth stating plainly. The first day of the final holds 8 frames and then 9, seventeen in all, and eighteen are needed. Even a player who wins every frame on the Sunday goes to bed at 17-0, one short. The champion is always crowned on the Monday.
When a closing session turns out not to be needed, it is simply not played. Nothing competitive is staged in its place.
When a session overruns and frames are pulled off
Eight frames can take two and a half hours. They can also take four. A run of long safety exchanges, a re-rack or two, a frame that goes to the colours with both players needing snookers, and a morning session is still going when the afternoon one is due to start on the same table.
The format has a blunt answer. When a session is running too long to finish before the next match needs the table, the tournament director stops it. No new frame is started, the players leave with frames unplayed, and those frames are said to have been "pulled off".
- Session runs longSlow frames mean the scheduled number cannot be completed before the next session is due to start on that table.
- No new frameThe players finish the frame in progress. The tournament director rules that the next one will not be started.
- Frames pulled offThe unplayed frames are removed from that session and the arena is turned round for the incoming match.
- Mid-match sessionIf the match has a later session still to come, the outstanding frames are added to the front of it.
- Closing sessionIf it was the match's last session, the players come back later to play to a finish, typically after the evening match on that table has ended.
The usual sequence when a session cannot finish before the next match is due on the same table. The tournament director makes the call in each case.
Where the unplayed frames go depends on where the match is. If it has another session to come, they are added to it, so a second-round match that managed only seven frames on its first morning may play nine in its second session. If the interrupted session was the last one, there is nowhere left in the schedule, and the players return to "play to a finish" once the table is free, which can mean starting again late in the evening after another match has concluded.
Evening sessions are different. Nothing is due on the table afterwards, so they run until they are done. This is how the Crucible produces finishes after midnight.
Why it is mostly a two-table problem
Pulling frames off is a feature of the first twelve days, when two tables each carry three sessions a day and the turnaround between them is tight. It is usually described as something that only happens while two tables are in use, and that is nearly right. The constraint is really the next match waiting for the table, and the two semi-finals share one table, alternating sessions, so a semi-final session can be cut short for the same reason. It happened in 2026, when the second session of the semi-final between Wu Yize and Mark Allen was stopped after the fourteenth frame of the match, two short of its allocation. The final is the only match in the tournament with nothing behind it.
Long frames are the usual cause. That fourteenth frame was the reason: it lasted 100 minutes and 21 seconds, the longest played at the Crucible up to the end of the 2026 championship. It took the record from a second-round frame between Mark Selby and Yan Bingtao in 2022 that ran to 85 minutes and 22 seconds. A session can absorb an ordinary slow frame. It cannot absorb one of those.
The 32 players: sixteen seeds and sixteen qualifiers
Half the field is there by right and half has earned it in the weeks before.
The sixteen seeds are the defending champion, who is seeded one regardless of his ranking, and the leading players on the world ranking list at the cut-off, which falls after the last ranking tournament before the championship. In most years the champion is inside the top 16 anyway, so the seeds are simply the top 16. Seeds two to sixteen follow ranking order with the champion lifted out. One result is that the world number one is often the second seed at the Crucible.
The ranking list is a rolling two-year tally of prize money, and the race for the sixteenth seeding place is one of the season's better subplots, because the difference between sixteenth and seventeenth is the difference between a fortnight's preparation and two or more qualifying matches. How the list is built is covered in our explainer on how the snooker world rankings work.
The other sixteen come from qualifying, staged in Sheffield in the fortnight before the main event. Everyone on the tour outside the top 16 enters, along with invited amateurs, and they are whittled down to sixteen survivors over several rounds of best-of-19 matches. The tiers, the invitations and the final round known as Judgement Day have a page of their own: World Championship qualifying and how it works.
The rarer case is a champion who has fallen outside the top 16 by the following spring. He keeps the number one seeding, and the direct places that remain go to the top fifteen on the list, so the player ranked sixteenth is the one who pays for it with a trip to the qualifiers.
Seeding buys rest, and it costs something too. A seed arrives at the Crucible having played very few best-of-19 matches all season, because outside the finals of tournaments and one small elite event in the spring almost nothing on the calendar is that long. His opponent has just won two, three or four of them in a row, on tables prepared to the same specification, a few miles across the city. First-round upsets at Sheffield are common enough that nobody treats them as freakish, and this imbalance in match sharpness is a large part of the reason.
Qualifiers are not ranked against one another once they are through. They are drawn at random against the sixteen seeds, one each. That randomness matters, because the sixteen qualifiers are never of even strength. In any year they may include a former world champion who has slipped down the list, a teenager making his debut and a veteran in his fifties, and a seed has no say in which he gets.
A fixed bracket with no re-draw
The seeds are placed in the draw before the qualifiers are known, and their positions do not move. Seed one is at the top, seed two at the bottom, and the two can meet only in the final. The rest are arranged so that, if every seed won, the higher seeds would meet the lower ones round by round.
| Quarter of the draw | Seeds due to meet in round two | Quarter-final if seeding holds |
|---|---|---|
| First | 1 v 16 and 8 v 9 | 1 v 8 |
| Second | 5 v 12 and 4 v 13 | 4 v 5 |
| Third | 3 v 14 and 6 v 11 | 3 v 6 |
| Fourth | 7 v 10 and 2 v 15 | 2 v 7 |
If seeding held all the way, the semi-finals would be one against four and two against three. It almost never does hold. But the bracket is the bracket: once the sixteen qualifiers have been drawn into their slots, every player can trace a route to the final and name the possible opponent at each stage. There is no re-draw between rounds, as there is in the FA Cup, and no re-seeding to reward the highest surviving seed with the weakest opponent.
A fixed bracket has consequences. One half can be stacked with former champions and the other left open. A qualifier who removes a top seed in the first round inherits that seed's path, favourable or otherwise.
The champion opens the tournament
By tradition the defending champion plays the first session of the championship, on the opening Saturday morning, and finishes his match that evening or the following day. It is a ceremonial slot and an awkward one. He has waited a year, the arena is full, and his opponent is a qualifier who has just won several matches in a row and has nothing to protect. First-time champions have a notably poor record in the following year's event, a pattern old enough to have a name, and our page on the Crucible curse goes through it.
Two tables until the quarter-finals, then one
For the first twelve days the Crucible's stage holds two tables side by side, separated by a dividing screen. Two matches are played at once, three sessions a day on each, and each half of the audience watches one of them.
The screen blocks the view but not the sound. A player lining up a frame-ball pink hears applause for a century on the other side. Referees on both tables pause for it. Players who have spent a career at the Crucible learn to wait a beat when the neighbouring crowd reacts, and newcomers learn the hard way.
Then, after the quarter-finals, the screen comes out. One table is set in the centre of the stage, the whole auditorium faces it, and the room that held two matches now holds one. Players say with unusual consistency that this is when it feels like a different venue: more space around the table, every seat in the house looking at the same shot, and no second match to share the attention.
There is an oddity in where the line falls. The quarter-finals, best-of-25 matches for a place in the last four, are still played two at a time with a partition between them, so a player can win the biggest match of his career to that point with half the theatre watching somebody else. It is the scheduling that requires it. Four quarter-finals of three sessions each are twelve sessions, and putting them on one table would add two days to the event.
For anyone following from home the two-table phase has its own effect. Two matches run at once in every session, the main broadcast picks between them, and the other is carried on a secondary feed. From the semi-finals there is nothing to choose between, and every frame of the last three matches is shown as it happens.
The switch changes the schedule as well. With one table there are at most three sessions a day in total, and the two semi-finals take turns on it across three days. The last five days of the championship contain only three matches. How the arena is laid out in each configuration, and where the seats are, is described in our guide to the Crucible Theatre as a snooker venue.
Seventeen days in Sheffield: how the calendar is built
The championship has run for seventeen days since the field reached 32 players in 1982. It ends, in normal years, on the first Monday in May, the early May bank holiday in the UK, which means it starts on the Saturday sixteen days earlier, somewhere between 15 and 21 April.
- 17Days
- 31Matches
- 80Sessions scheduled
- 12Days on two tables
Fixed features of the format. Sessions are the number scheduled if no match finishes a session early, so the true count is usually slightly lower.
The eighty sessions break down by round as 32 for the first round, 24 for the second, 12 for the quarter-finals, 8 for the semi-finals and 4 for the final. Two tables at three sessions a day give 72 slots across the first twelve days, and the first three rounds need 68 of them, so the schedule has very little slack. That is why overrunning sessions get cut rather than indulged.
The customary shape runs like this. The first round fills the opening Saturday to the first Thursday. The second round overlaps with the end of it and runs through to the second Monday. The quarter-finals take the Tuesday and Wednesday, all four of them, two per table. The semi-finals begin on the Thursday and finish on the Saturday. The final is Sunday and Monday.
| Days of the championship | Stage | Tables in use |
|---|---|---|
| 1 to 6 | First round | Two |
| 6 to 10 | Second round | Two |
| 11 and 12 | Quarter-finals | Two |
| 13 to 15 | Semi-finals | One |
| 16 and 17 | Final | One |
Within that frame the sessions of a single match are scattered. A first-round match might have its two sessions on the same day, morning and evening, or split over consecutive days. A second-round match usually takes parts of two or three days. The quarter-finals are the most compressed of the multi-session matches, three sessions inside roughly thirty-six hours, and the semi-finals the most stretched, four sessions over three days with the other semi-final occupying the table in between. The order of play for a given year fixes all of this once the draw is known.
The daily load on the arena falls away sharply once the second table goes. Through the first twelve days there are six sessions a day, three on each table, starting from mid-morning and often running past eleven at night. The first day of the semi-finals has two sessions, the next two days have three each, and each day of the final has two. A venue that staged six sittings on the first Saturday stages a single match across the whole of the last Monday, and the building's attention narrows in the same proportion.
The one clear break from the calendar was 2020, when the pandemic pushed the championship back to 31 July, with the final in mid-August.
Rest days, and why players call it a marathon
The champion plays a maximum of sixteen sessions in seventeen days. Put like that it sounds manageable. The difficulty is in how unevenly they fall.
A seed who plays on the opening weekend can be through to the second round by Sunday and then have nothing to do until the following Thursday or Friday. Another, drawn at the far end of the first-round schedule, finishes on the first Thursday and may be back at the table within two days. Neither arrangement is obviously better. A long gap means rest and practice, but it also means days in a hotel with a match to think about and the rhythm of competition gone. A short one keeps a player sharp and gives him no time to recover from a hard match.
The squeeze is tightest at the end. Quarter-finals finish on the Wednesday, some of them late in the evening, and the semi-finals start on the Thursday. The first semi-final is scheduled to conclude on the Saturday afternoon and the second on the Saturday night, and the final begins on the Sunday afternoon, so one finalist has an evening longer to recover than the other. Over the last five days a player who goes the distance could play 68 frames across eight sessions.
Then there is the plainer fact of being in Sheffield for two and a half weeks, playing the same event, with the pressure rising each round. The physical demand of snooker is modest. The demand on concentration is not, and it accumulates. Players who have won the title describe the second week less as playing well than as continuing to function, and the marathon comparison, worn as it is, describes something real: the event is paced, and it is commonly lost by the player who spent too much in the first week.
How the format arrived: from fortnight-long finals to the best of 35
Nothing about the present format was inevitable. For its first four decades the championship looked nothing like it.
| Year | What changed |
|---|---|
| 1927 | First championship, won by Joe Davis |
| 1946 | Davis beats Horace Lindrum 78-67 in a final of 145 frames lasting two weeks |
| 1964 | Title revived on a challenge basis after a seven-year gap |
| 1969 | Knockout tournament restored; John Spencer wins |
| 1977 | Championship moves to the Crucible with 16 players and a best-of-49 final |
| 1980 | Field grows to 24; final cut to best of 35 |
| 1982 | Field grows to 32 |
| 1997 | Semi-finals lengthened from best of 31 to best of 33 |
The early championships were closer to a series of long private matches than a tournament. Entrants were few, rounds were played at different venues over months, and finals ran for a week or a fortnight because the gate money came from selling many sessions of one match. The 1946 final at the Royal Horticultural Hall in London, Joe Davis's last, was played to a finish over 145 frames.
A dispute between the leading players and the governing body split the title in 1952, with most of the professionals leaving to stage a championship of their own. That event dwindled in turn and was last played in 1957, and there was no contest of any kind until 1964. It came back as a challenge system, in which the holder, John Pulman, defended against a single challenger at a time, some of the challenges being decided over a series of matches.
The modern era is dated from 1969, when the title was again decided by a knockout. Even then the matches were enormous. The 1969 final was the best of 73 frames. Through the 1970s the event moved between venues in London, Birmingham, Manchester and Middlesbrough, and was twice taken to Australia, for the championship played late in 1970 and again in 1975.
The Crucible fixed the place in 1977 but not yet the format. The first three finals there were the best of 49, 49 and 47 frames. When the field expanded to 24 in 1980 the final was trimmed to 35 to make room, and it has not changed since. The field reached 32 in 1982, which set the five-round structure and the seventeen days. The semi-finals went from best of 31 to best of 33 in 1997, and that was the last adjustment to the length of any round.
So the format that feels immemorial dates, in its exact present form, only from 1997, and its core from the early 1980s. The fuller story is in our history of snooker, and the winners under each system are in the list of snooker world champions.
The World Championship format against the UK Championship and the Masters
The three events that make up the snooker Triple Crown are grouped together for their prestige, but as tests they are far apart.
At the UK Championship every match from the last 32 to the semi-finals is the best of 11 frames, played in a single session, and the final is the best of 19 over two. The Masters is an invitation event for sixteen players on one table, also best of 11 throughout until a best-of-19 final. In both, a player has one session to win or go home in every round but the last.
The UK Championship was once much closer to the world's in character. Its final was the best of 31 frames for years, and its earlier rounds were multi-session matches. It was shortened in stages, and the best-of-11 format through to the semi-finals is a product of the 2010s. The Crucible is now the only one of the three, and one of very few places on the tour at all, where matches before the final run to more than one session as a matter of course.
That makes the first-round match at Sheffield, best of 19 over two sessions, the same length as the final of the other two. A player can win the Masters by winning 28 frames. At the Crucible, 28 frames gets him to the middle of a quarter-final.
The case for shortening it, and why it has not happened
The argument comes round most years. The championship is long for television, long for players and long for a casual audience raised on formats that finish in an evening. Some leading players, Ronnie O'Sullivan most prominently, have said in public that the event is too long and that shorter matches would suit them better. The usual proposals are to cut the first round to best of 17 or fewer, to bring the semi-finals back to three sessions, or to lose a day or two from the calendar.
The case against is that the length is the thing being tested. Over eleven frames a hot hour can beat a better player. Over 25 or 33 it rarely does, and over five rounds it almost never does. The roll of honour at the Crucible has fewer surprises on it than that of any short-format event, and the sport treats that as evidence the format finds the best player.
There is a commercial side as well. Eighty sessions are eighty sets of tickets and seventeen days of broadcast hours, and a shorter event has less of both to sell.
Our judgement is that the long format is the championship's main asset and the tour appears to know it. Almost everything else on the calendar has been shortened over the past fifteen years, which has made the Crucible more distinctive by contrast. A best-of-35 final that can stand at 8-0 early on the Sunday and 17-17 late on the Monday is a different kind of contest from anything else the sport stages, and the finals that have gone to a deciding 35th frame, the 1985 final between Dennis Taylor and Steve Davis first among them, are remembered because of the two days that came before the last ball.
The format is not beyond criticism. The uneven rest days are a real unfairness that a fixed bracket and a two-table schedule make hard to remove, and late-night finishes after pulled-off frames serve nobody well. Those are scheduling problems, though, and they could be eased without touching the frame counts. The distances themselves have survived every review since 1997.
For more on the rules and the tour, the England sport hub collects the rest of our snooker guides.