Esports fields scale in a way physical sport rarely does — an open qualifier can take 256 entries from a Discord post. Knockout depth grows logarithmically, which is why it handles those numbers at all: a 256-team single elimination bracket is 255 matches over 8 rounds, with no byes anywhere in the draw because 256 is a power of two. Doubling the field only ever adds one more round — 512 entrants is 511 matches over 9.
The browser generators go up to a 64-team bracket, which is the largest draw that renders comfortably on a phone. Above that the draw is the same shape with more rounds in front of it: the round of 256 feeds a round of 128, then 64, and from there the bracket you can preview here is the back half of the qualifier.
The cost is that half your entrants play once. For a free open qualifier that is often acceptable. For a paid-entry event or a league stage it is not, and the format has to guarantee more games. Swiss pairs teams on equal records without eliminating anyone, so a 64-team, six-round Swiss is 192 matches with every team playing all six — the standard shape for large chess and card-game events, and increasingly for shooters.
Double elimination sits between the two: every team gets a second life, at roughly double the match count, and it runs live up to a 64-team bracket with the grand final reset included. If you are choosing between the two knockout styles, single vs double elimination covers the trade in detail, and the double elimination bracket generator has an interactive draw you can test your field size against.