Explore how every NCAA tournament seed has actually done since 1985, then build your own bracket or let a tunable model fill one in for you.
▶ Open the live app · works on phone and laptop
- 40 years of real results — every men's tournament from 1985 to 2025 (no 2020); pick any mix of years or use presets like "Last 10".
- Seed-vs-seed history — how often a seed lost to each opponent seed, with the actual win-loss counts.
- Title odds and upset counts — championship % by seed and how many upsets each tournament had.
- Any past bracket — pick a year to see the full real bracket.
- Build your own bracket — click teams to pick winners; hover to see historical win rates for that matchup.
- Tunable simulator — a skill-gap slider and curve shape set how dominant top seeds are, and the charts, odds and upset forecast update live.
- Auto-fill — simulates a whole 63-game bracket and shows its upset count and the odds of a perfect bracket (think 1 in 29 quadrillion).
A single HTML page with plain JavaScript and Chart.js, plus a JSON file of seed results.