March Madness bracket, explained: How the field of 68 teams is seeded for NCAA Tournament

09-03-2024
9 min read

March Madness here!

Before the tournament gets started, the selection committee has to put together one of the most beautiful (and complex) sights in sports: The bracket. 

Filling out your bracket at home can be difficult, but the committee's job of putting the field of 68 teams together might be even tougher.

Thanks to rules regarding which opponents a team can face in the tournament and how far a team has to travel for their respective regional match-ups, building the bracket isn't as simple as ranking all of the teams 1-68. Games also go right up to until the start of the bracket reveal show, so the committee has to consider several scenarios even in the final hours. 

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Here's how the 68 teams are chosen, including how they're seeded in the bracket and who is making the call behind the scenes.

NCAA Tournament automatic bids

When the bracket is revealed on Selection Sunday, 32 teams have already clinched an NCAA Tournament bid and taken their in/out status out of the committee's hands.

If a team wins its conference tournament, it automatically clinches a spot in the NCAA Tournament. The four lowest-seeded teams to receive an automatic bid, according to the committee, play in the First Four for two spots in the Round of 64, but the rest are placed in Round of 64 matchups.

Some of the teams who clinch an automatic bid would have been selected to the tournament even if they hadn't won their conference tournament. For example, 2022 national champion Kansas was good enough to reach the NCAA Tournament even if it hadn't won the Big 12 Tournament.

MORE: Updated list of NCAA Tournament automatic bids

For many smaller conferences, winning the conference tournament is typically the only way to secure an NCAA Tournament bid. 2022's Cinderella story, Saint Peter's, only earned a spot in the tournament by winning the MAAC Tournament. 

Occasionally, a conference tournament winner isn't eligible for the NCAA Tournament because it recently transitioned from the Division II level to Division I. That was how Jacksonville State earned a bid last season despite Bellarmine winning the ASUN Tournament. 

NCAA Tournament at-large bids

With all 32 automatic bids settled by the time the bracket is revealed, the selection committee chooses 36 "at-large" teams to fill out the rest of the field. 

It's up to the committee members to debate and vote in these teams based on their total body of work. That means games from November and December, in theory, count as much as games in February and March.

The committee starts championship week by identifying 25 "locks" and spends the rest of the week debating the teams closer to the tournament bubble. 

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By Selection Sunday, 36 teams are chosen based on their full body of work -- that includes not just win-loss record but also strength of wins, strength of losses, and metrics such as NCAA Evaluation Tool (NET). The 36 at-large teams are added to the field of 68 along with the 32 automatic bids.

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The four lowest-seeded teams among the 36 play in the First Four in Dayton for the final two spots in the Round of 64.

NCAA Tournament seeding rules

The committee seeds the teams 1-68 on Selection Sunday, with contingency plans in place to change the order based on the results of Sunday's games.

However, it's not as simple as going line-by-line and filling out the bracket at that point. The committee also has to consider a few rules, including restrictions on when teams can play opponents from the same conference.

Any two teams that play each other twice in the regular season can't face off again until at least the Sweet Sixteen. If two teams played each other three times during the season (twice in the regular season, once in the conference tournament), they can't face each other until at least the Elite Eight. This is one reason why it took so long for rivals Duke and North Carolina to meet in the NCAA Tournament.

These rules mean the NCAA has to consider all possible Round of 32 and Sweet Sixteen matchups when fitting teams into each region. 

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The committee tends to avoid in-conference matchups early in the tournament, but they do happen occasionally. In 2019, Michigan State met Minnesota in the Round of 32 for a Big Ten showdown since they only played each other once during the season. The next weekend, ACC teams Duke and Virginia Tech met in the Sweet Sixteen. 

The committee also tries to avoid rematches of non-conference regular season matchups "if possible" in the Round of 64 and Round of 32. 

NCAA rules also state that the committee "shall not place teams seeded on the first four lines at a potential 'home-crowd disadvantage' in the first round." That means any of the 16 teams seeded 1-4 cannot play close to their opponent's location in the first round.

For example, if Indiana was matched up with UAB (University of Alabama-Birmingham) in the Round of 64, the committee is not able to put the game in Birmingham and would have to put the two teams in one of the other seven first round locations. The rule attempts to prevent highly-ranked teams from having to play in a de facto road environment. 

Sometimes, these rules result in teams moving to an entirely different seed than the committee originally selected. NCAA rules state, "A team may be moved up or down one (or in extraordinary circumstances) two lines from its true seed line when it is placed in the bracket if necessary to meet the principles."

NCAA Tournament regions

The No. 1 overall seed is given the chance to select its region for the first weekend of the tournament, as well as its specific location.

For example, if Purdue is the No. 1 overall seed, it can choose to play in Detroit for the first and second round and thus be placed in the Midwest region. If UConn is the No. 1 overall seed, it can choose to play in the region that plays Sweet Sixteen and Elite Eight games in Boston. 

The NCAA says the committee attempts to keep top seeds in their "area of natural interest," though the rest of the rules often force teams to play in a region nowhere near their campus.

This is a principle, not a rule, so the NCAA says it would not place the top No. 2 seed in the same region as the top No. 1 seed just to accommodate the No. 2 seed's location. 

NCAA Tournament selection committee members

Below are the 12 members of the selection committee this year. Committee members serve five-year terms.

  • Scott Barnes (Athletic director, Oregon State)
  • Renee Baumgartner (Athletic director, Santa Clara)
  • Greg Byrne (Athletic director, Alabama)
  • Barry Collier (Athletic director, Butler)
  • Mark Coyle (Athletic director, Minnesota)
  • Bubba Cunningham (Athletic director, North Carolina)
  • Keith Gill (Commissioner, Sun Belt Conference)
  • Arthur Johnson (Athletic director, Temple)
  • Charles McClelland (Commissioner, SWAC)
  • Martin Newton (Athletic director, Samford)
  • Jamie Pollard (Athletic director, Iowa State)
  • Tom Wistrcill (Commissioner, Big Sky)

Members leave the room when their school is brought up in discussion. For example, North Carolina AD Bubba Cunningham will not be in the room for any debate about the Tar Heels. Conference representatives also leave the room for discussions about teams in their league.