The Birth of the Bracket: A Short History of the NCAA Tournament's Expansion

March Madness feels eternal — the 68-team bracket, the buzzer-beaters, the office pool — but the tournament that captivates the country every spring is the product of nearly a century of expansion, each step driven by money, fairness, or both. It began in 1939 with eight teams and no television. This is the short history of how the bracket grew, and how each enlargement quietly rewrote the math of the Cinderella story.

The one-sentence version: the tournament got bigger whenever the old field left a deserving team out or a new revenue stream made inclusion worth it — and every expansion gave the underdog a little more room to dream.

1939: eight teams and a debut

The first NCAA men’s basketball tournament was held in 1939, an eight-team field, and Oregon won the inaugural title. It was a modest event — overshadowed at the time by the older National Invitation Tournament — and it reportedly even lost money in its first year. There was no television, no bracket pool, none of the spectacle to come. But the structure was the seed of everything: gather the best teams, play single elimination, crown one champion on the floor rather than in a poll.

1975: at-large teams change the premise

For decades the tournament was built around conference champions — win your league, get in; finish second, stay home, no matter how good you were. That created an obvious unfairness: a powerhouse could lose its conference race to another powerhouse and miss the field entirely, while a weaker league’s champion got a bid. In 1975 the NCAA broke that rule, allowing at-large teams — squads that didn’t win their conference but were judged among the best available — into the bracket for the first time.

This is a bigger deal than the date suggests. The moment you admit at-large teams, you need a body to choose them, which is the origin of the selection committee and the entire modern ritual of Selection Sunday, the bubble, and arguments over who got snubbed. The tournament stopped being a tidy playoff of champions and became a curated field of the best teams — a value judgment about access that the sport is still litigating today, much as football did on its road from the BCS to the playoff.

1985: the 64-team bracket and the birth of March Madness

The tournament as we know it arrived in 1985, when the field expanded to 64 teams. Sixty-four is a beautiful number for a single-elimination bracket: it’s a clean power of two, so every team plays its way through six rounds with no byes and no awkward play-in math — 64 to 32 to 16 to 8 to 4 to 2 to 1. This is the version that turned into a cultural phenomenon. The bracket fit on a single sheet of paper, the round names (Sweet 16, Elite Eight, Final Four) snapped into place, and the office pool was born.

It’s no coincidence the explosion in popularity tracked the 64-team era. A bigger field meant more conferences represented, more games to televise, and — crucially — more first-round matchups between a juggernaut and a tiny school nobody had heard of. The 64-team bracket is the machine that manufactures Cinderellas, the structure behind everything we describe in what March upsets have in common.

2001 and 2011: 65, then 68

The last two expansions were smaller and more technical. In 2001, the field grew to 65 with the addition of a single opening-round game — a play-in to get the bracket from an unwieldy 65 down to the clean 64 the rest of the tournament needed. Then in 2011, the tournament settled at 68 teams with the introduction of the First Four: four opening games, played in Dayton, that whittle 68 down to 64 before the main bracket begins. That’s the format we have today.

I’m laying out the milestones I’m confident about. The intermediate field sizes between 1975 and 1985 shifted around more than once as the tournament crept upward year to year, and I’d rather not hand you a specific number for a given season that I can’t stand behind — the clean landmarks below are the ones that matter.

Why it kept growing

Three forces show up at every expansion:

• Television money. More teams meant more games meant more inventory to broadcast and sell. The tournament’s media value is the financial engine of college athletics, and a bigger bracket is a bigger product.
• Fairness to strong non-champions. The 1975 at-large reform was explicitly about not punishing a great team for sharing a conference with another great team. Every expansion since has, in part, been about reducing the number of deserving teams left on the doorstep.
• Access for more conferences. A larger field guarantees automatic bids to more leagues, spreading the tournament’s reach — and its money — across more of the country. That access debate is exactly the mid-major at-large math that animates every bubble discussion.

How a bigger field changed Cinderella math

Expansion didn’t just add teams; it changed the kind of drama the tournament produces. A small, champions-only field is mostly heavyweight bouts — few mismatches, few miracles. The jump to 64 deliberately seeded powerhouses against small-conference champions in the first round, which is precisely where upsets live: a No. 12 over a No. 5, a No. 15 shocking a No. 2. More entrants meant more underdogs with a puncher’s chance, and single elimination meant one hot shooting night could end a favorite’s season. The bracket got bigger, and in doing so it became an upset-generating machine — the reason a perfect bracket is effectively impossible and the reason a small school can author one of the most improbable seasons in sports.

From eight teams in an arena that lost money to a 68-team spectacle that helps fund an entire industry, the tournament’s growth is a story of the same instinct repeated: let one more deserving team in, sell one more game, give the underdog one more shot. Sixty-eight is the current answer. If history is any guide — and there’s perennial talk of going larger still — it probably isn’t the last.