March Madness odds: why no one fills a perfect bracket

• Even strong favorites lose sometimes.
• A perfect bracket is close to impossible.
• Pools reward later rounds more.
• Pick a champion others overlook in big pools.

Men’s tournament format.

With 63 games and two choices each, there are 2 to the 63rd power possible brackets, which is 9,223,372,036,854,775,808. If you flipped a coin for every game, that is your chance of a perfect bracket.

Real fans do better, because favorites win more often than half the time. Estimates using seed history put the odds somewhere in the billions or hundreds of billions, depending on the model. Either way, it is far longer than any lottery jackpot.

That is why big contests offer huge prizes for a perfect bracket. No verified perfect men’s bracket has ever been recorded in a major online contest.

Number 1 seeds almost always win their first game. Only two 16 seeds have beaten a 1 seed in the men’s tournament: UMBC over Virginia in 2018 and Fairleigh Dickinson over Purdue in 2023.

The 5 vs 12 game is famous for upsets, with the 12 seed winning about a third of the time. The 8 vs 9 game is close to a coin flip. That is why most brackets include at least a few upsets in the first round.

Upsets still need to be picked correctly. Choosing many upsets lowers your expected score, because each one is still less likely than the favorite.

1. 1

   Step 01

   Read the scoring

   Later rounds often score more.

2. 2

   Step 02

   Pick a strong champion

   Most points sit there.

3. 3

   Step 03

   Add a few upsets

   Mostly 5-12 and 8-9 types.

4. 4

   Step 04

   Think about the pool

   Big pools reward different picks.

5. 5

   Step 05

   Submit before tip-off

   Deadlines are strict.

Most bracket pools score later rounds more heavily, such as 1 point per first-round win and 32 for the champion. Getting the champion right often matters more than all the first-round picks combined.

In a small office pool, picking the favorites often wins. In a pool with hundreds of entries, you may need a champion fewer people chose, because if everyone has the same favorite you cannot gain on them.

Betting on single tournament games or futures is legal at licensed sportsbooks in many states, though some states limit bets on in-state college teams. Bracket contests may follow different rules.

Chasing a perfect bracket

The odds are tiny.

Picking too many upsets

Each is less likely.

Ignoring scoring

Later rounds matter most.

Following the crowd in big pools

You cannot gain ground.

• Futures bets →Betting on a champion.
• Point spread →Single-game lines.
• Implied probability →Odds to percent.
• Legal betting states →Where you can bet.

Tap a resort — each row opens that casino’s White Gambling page (hours, game mix, floor facts). Venues with this game in official counts, sorted high to low.

Browse all Las Vegas casinos →

A 90-second guide cannot cover every table moment. Tap a group, then a question — answers are short paragraphs, not one-liners.

1. Wikipedia — NCAA Division I men’s basketball tournament Not from a registry (Reference source, not an official registry) · accessed Oct 15, 2026Format and seed history
2. NCAA — Men’s basketball tournament Not from a registry (Reference source, not an official registry) · accessed Oct 15, 2026Brackets, seeds and results
3. Wizard of Odds — Sports betting Not from a registry (Reference source, not an official registry)?The gaming industry’s standard reference for casino-game math, by actuary Michael Shackleford. Not an official registry; our calculators compute these numbers independently. · accessed Oct 15, 2026Sports betting math
4. National Council on Problem Gambling — Help and resources Not from a registry (Reference source, not an official registry) · accessed Oct 15, 2026Free, confidential help: call or text 1-800-GAMBLER