20-player Swiss pairing sheet
5 rounds for 20 players. Nobody is knocked out; pair by score every round.
Prints on one Letter or A4 page. Type your own names on the home page or after you click Run this live.
Round 1 for 20 players
Split the ranked field in half and pair across: 1 v 11, 2 v 12, 3 v 13, 4 v 14 and so on down to 10 v 20. That is 10 games in round 1 and in every round after it.
Why that many rounds
If every game had a winner, about 10, 5, 3, 1, 1 players would still be unbeaten after rounds 1 to 5. With 20 players, 5 rounds leave one player with a perfect score, which is the reason for the number. You could add a round to be sure, at a cost of 10 games.
Games and time
5 rounds of 10 games make 50 games. At 30 minutes a game that is 25 h of table time, or 2 h 30 min if you have 10 tables and every round finishes together; with half as many tables, 5 h.
How the field splits, round by round
Suppose every game has a winner and the results fall evenly. This is roughly how 20 players spread out, shown as players on each number of wins. The pairing engine always pairs inside a group first, so the groups below are the pairings you will make.
| When | Players on each score | Groups to pair |
|---|---|---|
| After round 1 | 10 on 1, 10 on 0 | 2 score groups |
| After round 2 | 5 on 2, 10 on 1, 5 on 0 | 3 score groups |
| After round 3 | 3 on 3, 8 on 2, 8 on 1, 3 on 0 | 4 score groups |
| After round 4 | 1 on 4, 5 on 3, 8 on 2, 5 on 1, 1 on 0 | 5 score groups |
| After round 5 | 1 on 5, 3 on 4, 6 on 3, 6 on 2, 3 on 1, 1 on 0 | 6 score groups |
What round 2 looks like
If the higher seeds win round 1, the winners meet each other in round 2: 1 v 6, 2 v 7, 3 v 8, 4 v 9, 5 v 10. The losers meet inside their own group: 11 v 16, 12 v 17, 13 v 18, 14 v 19, 15 v 20. If results go differently the pairings change, so make round 2 only when round 1 is finished.
A top-4 cut from 20 players
With 5 rounds, about one player finishes unbeaten. To fill a top 4 you would usually reach down to 4 wins, which about 4 players reach. That fills the 4 places exactly, so ties rarely matter for the cut.
Time by number of tables
Every round has 10 games. The columns show how long a round takes and how long the whole event takes at 30 minutes a game, plus 10 minutes between rounds to pair and seat players.
| Tables | One round | Whole event |
|---|---|---|
| 1 | 5 h | 25 h 40 min |
| 5 | 1 h | 5 h 40 min |
| 10 | 30 min | 3 h 10 min |
If your field changes
Dropping to 16 players gives 18 fewer games, and a round shorter. Going up to 24 players gives 10 more games, in the same number of rounds. Page sizes differ by the formats the numbers allow, so check the nearest size before you commit.
Questions
How many rounds for 20 players?
5. Add one round if you want a single undefeated winner to be very likely.
What if two of the 20 players tie on points?
Buchholz, the sum of your opponents' scores, decides it. Then a playoff game if the prize needs one.
Is 20 players too many for Swiss?
No. Swiss suits fields too big for a round robin (which would need 190 games) and too long for elimination.
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