Running a trading card game tournament starts with one question: how many Swiss rounds? Too few and the standings are a coin-flip; too many and players sit around all day. This calculator gives you the recommended rounds for your attendance, the mathematical minimum, and the records players need to make the cut.
How it works
Swiss pairing matches players on equal records each round. Every round halves the pool that can still be undefeated, so to produce a single undefeated player you need at least:
minimum rounds = ⌈log₂(players)⌉
For example 32 players give ⌈log₂(32)⌉ = 5. Official organisers publish a fixed table keyed to attendance bands (the long-standing DCI table), which this tool uses for the recommended figure: 4 rounds up to 16 players, 5 up to 32, 6 up to 64, 7 up to 128, and so on.
Scoring is win = 3, draw = 1, loss = 0, so after r rounds the maximum is 3r points. A player who loses at most twice finishes “X-2” with 3(r − 2) points, which reliably makes a Top 8 at most events.
Example
With 32 players the tool recommends 5 Swiss rounds and a Top 8 cut. The maximum is 15 points (5-0). An X-2 record is 9 points and almost always advances, though the exact cutoff shifts with draws and tiebreakers.
Notes
The recommended rounds match the standard attendance table used across Magic, Pokémon and Yu-Gi-Oh; the minimum is the pure ⌈log₂(players)⌉ rule for a clean champion. For sanctioned events, always confirm the current official tournament rules for your game and event tier, since premier events sometimes add a round or run a larger cut. All calculations run locally in your browser.