Calculation methods
The formulas, worked examples, assumptions and limits behind every tool.
Knockout bracket ↗
Bracket size is the next power of two. Seed order separates the top seeds; missing seeds become byes. A completed tournament has N − 1 played matches.
Example: Eight players need three rounds and seven played matches. Six players use eight slots with two first-round byes.
Input order is seed order. Shuffle only when you want a random draw. Changing an earlier winner clears incompatible downstream selections. Results remain on this page only; export before leaving.
Round robin ↗
Single round robin has N(N − 1) ÷ 2 matches. The circle method rotates every participant except the first. A second leg reverses pair order.
Example: Five players produce five rounds, two games and one bye per round: ten matches in total.
Every pair meets once per leg, with no participant playing twice in a round. Left/right order is not a guarantee of balanced home advantage. No scores or league standings are maintained.
Random groups ↗
Shuffle with Fisher–Yates using browser crypto randomness, then deal participants across groups in order. Group sizes differ by at most one.
Example: Eight participants and three groups produce groups of 3, 3 and 2. Click Draw groups to generate a new random allocation.
The first preview uses input order until you choose Draw groups. This tool does not handle seeding pots, skill balancing or auditable public lotteries.
Court schedule ↗
Each round is split into ceil(matches ÷ courts) time slots. A new round starts after all matches in the previous round finish and the slot gap passes.
Example: Eight players, two courts, 20-minute matches and 5-minute gaps: seven rounds, 28 games, 14 time slots. Starting at 09:00 ends at 14:45.
This conservative schedule avoids double booking and includes the gap between rounds. It does not optimize rest fairness or mix adjacent rounds. Times are local labels with day offsets, not timezone-aware bookings.
Units and numerical limits
Conversions use 1 inch = 2.54 cm, 1 mile = 1.609344 km, and 1 avoirdupois ounce = 28.349523125 g. Empty, non-finite, out-of-range and unsupported values are rejected. Displayed values are rounded; calculations retain precision. Input-specific limits are reported alongside the field when exceeded.