Tournament Simulator

A calculator for all of your tournament math needs. The defaults are set to match the typical rules for Magic: The Gathering events, but you can change the settings to use this for pretty much any Swiss-style tournament structure.

See the footnotes for more information about each setting, and the technical details at the bottom for implementation details. If you have any questions or suggestions for improvement, please get in touch.

Tournament details:







Player details:4




Multiplayer settings:





Theoretical distribution:

Points Players Cumulative

Your chances:

Points Chance Cumulative

The most likely match point distributions among the top cut:

Intentionally drawn matches:

Technical details:

Comparison to other tools:

There are several other tools that people have made over the years to help with tournament math. A list of the ones I'm aware of along with their limitations:

This calculator is intended to combine their functionality into a single package, along with adding other useful features like custom tiebreakers and multiplayer math. If you notice anything that it can't do but you wish it could, please let me know and I'll see about adding that functionality.

Footnotes

1

If the tournament gives some players byes, enter them here, separated by commas. For example if 30 players get a round 1 bye and half of those players get another bye round 2, you'd enter "30, 15".

2

Unintentional draw. In multiplayer events, this probability should include both draws due to running out of time and draws that occur as a compromise to a kingmaking situation.

3

"Target standing" is whatever place on the standings players are trying to maximize their chance of reaching in the Swiss. In a tournament with a cut to top 8, this would be "8". For a day 2 cut you can change this to care about a specific number of match points, or being tied with a certain standings position.

4

If you want to know a specific player's chances of making the cut, enter their info as of the last round to have ended.

5

Enter the number of the last round to have finished

6

If you don't know your average opponent match win percentage you can leave this blank and the simulator will guess the most likely value based on your match points and round.

7

For more accurate results, you can use this field to enter multiple player details. Simply enter the player's points and then OMW%, then repeat for all other players. e.g. you could enter "6 50 3 66.5 3 66.5 0 50" as the full standings of a 4 player event. (Any whitespace character works as a separator.) Alternatively if you have access to the event standings on MTG Melee, you can copy the entire standings page text into this box and the calculator will parse out the individual players and point values.

For best results, include all players that could potentially get to your number of points within the number of rounds remaining, assuming you draw every future round. e.g. if you have 15 points and there are 2 rounds left, you'll want to enter everyone that has at least 11 points in the current round. (Note that this still cannot perfectly predict your results, because it doesn't know which players have already played which other players.)

Note that if you enter standings while a round is ongoing, you may be entering invalid data, since some players have finished their match and others have not. This will lead to incorrect results.

8

If the number of players in the event isn't divisible by the desired number of players per match, smaller games will be made to avoid byes if possible.

9

A draw includes all players in a multiplayer match. There's no possibility of some players in a single match drawing and some others losing.

10

This field dictates the chance of winning based on who goes first. (Conditional on not being a draw.) For example, if in a 4-player game the first player in turn order has a 40% chance of winning and the other players each have a 20% chance of winning, enter "40, 20, 20, 20". (Integers only.)

11

This is similar to what the classic "swiss triangle" tools do, except it's more accurate because it doesn't assume that pairdowns always win.

12

For example, if a player with 3 points is paired against a player with 0 points, the result of this match is 0.5 players with 6 points, 1 player with 3 points, and 0.5 players with 0 points.

13

These programs are all closed-source, so their exact algorithms are a secret.

14

Notably Wizards Eventlink doesn't seem to respect this floor, and instead uses a floor of 1/3.

15

This minimum is generalized to multiplayer as floor((1 / (number of players in a match + 1)) * 100) / 100.

16

For example, if the only players in a certain point bracket are players A, B, C, and D, and player B has already played both A and D, there is a legal pairing among themselves: A plays D and B plays C. But this simulator isn't guaranteed to find that pairing, and it may instead pair A vs. C and give pairdowns19 to both B and D.

17

e.g. if playing it out gives that player a 50% chance of making the cut, they'll only ID if it gives them at least 85% to make it. If playing gives them a 90% chance, they'll only ID if it gives them a 100% chance.

18

If it didn't limit the comparisons to the top of the standings, the results would be meaningless on large tournaments. There are so many different ways the finals standings could look that you could simulate the same large tournament thousands of times and get a slightly different final standings printout every time, making it impossible to pick one that's meaningfully the "most common". It makes more sense to just look at, say, the top 12, and pick the most common point distributions within all the different top 12s.

19

Or byes if this is the lowest bracket.

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