Why powers of two appear
A knockout round halves the field: 32 becomes 16, 16 becomes 8, and so on. The cleanest complete tree therefore has 2, 4, 8, 16, 32 or 64 slots. Other entrant counts are expanded to the next size and the unused slots become automatic advances.
The underlying match count is still the number of real entrants minus one. A 6-entrant single-elimination event has five competitive matches and two automatic byes.
Seeded byes
In a seeded draw, the highest seeds should not all face a difficult first round while lower seeds receive every free pass. Balanced bracket positions spread byes across the tree and place the strongest seeds where the first round is predictable without making the entire path deterministic.
Use a seeded order when prior ranking, qualification or league position should matter. Record the seed list with the event so participants can see the rule before matches begin.
Random draws
For a casual event where every entrant has equal status, shuffle the list before slotting it into the bracket. Keep the visible draw seed if someone needs to reproduce the order. A random draw should be a transparent input transformation, not a hidden winner generator.
If you mix protected seeds with random positions, write that rule down. Fairness is easier to defend when the random and fixed parts are visible.
Build it now
Use the format that fits your event and keep this guide open while you set up the list.