The Round of 64 in March Madness officially tips off this Thursday. Professional and amateur bracketologists alike are making their picks and stipulating which underdogs could defy the odds and pull off stunning upsets. While three out of four of this year’s No. 1 seeds are expected to make the Final Four, history tells us that not all upsets are created equal. While No. 12 seeds love ruining dreams, and No. 14 seeds occasionally shake up the bracket, some matchups have been more predictable than others. Using historical data, I analyzed the likelihood of each seed beating every other seed.
Historical March Madness Winning Percentage By Seed
Since the NCAA expanded the men’s basketball tournament to 64 teams in 1985, there have been 39 seasons of March Madness, creating a rich dataset with over 2,500 individual matchups. This vast history includes countless Cinderella stories and enough results to reveal meaningful patterns in upsets and seeding trends. By analyzing this deep statistical pool, we can identify which seeds consistently overperform or underperform expectations. Below is a heatmap illustrating the historical winning percentages of each seed when facing another seed.
The bottom-left to top-right diagonal represents the winning percentage of teams against opponents of the exact same seed. These matchups occur only in the First Four, Final Four, or National Championship games. Notably, No. 6-9 and No. 15 seeds have never faced a team of the same seed in tournament history.
The top-left to bottom-right diagonal displays winning percentages in Round of 64 matchups, which provide the most data. As expected, higher-seeded teams generally have a better winning percentage, but certain matchups offer more parity than others. The No. 8 versus No. 9 matchup is historically the most balanced, while the No. 1 versus No. 16 matchup is the most lopsided. Only two No. 16 seeds have ever pulled off the upset: UMBC over Virginia in 2018 and Fairleigh Dickinson over Purdue in 2023.
Upset-Minded Seeds In March Madness
No. 15 Seeds
Despite a difference of only one slot in seeding, No.15 seed dramatically outperform No. 16 seeds in the tournament and are over five times more likely to win their first-round game. Since 2021, three different No. 15 seeds have defeated a No. 2 seed including Princeton beating Arizona in 2023, Saint Peter’s beating Kentucky in 2022, and Oral Roberts beating Ohio state in 2021. Even more impressively, No. 15 seeds don’t just stop at one upset. After advancing past the Round of 64, they have posted a surprising 4-7 record in the second round, proving that when a No. 15 gets hot, they can make a real run.
No. 12 Seeds
The No. 5 versus No. 12 matchup has become synonymous with bracket chaos, and for good reason. Historically, No. 12 seeds win 33% of their matchups against No. 5 seeds—meaning that, on average, at least one No. 12 seed advances each year. To put this in perspective, a No. 12 seed has nearly the same upset potential as a No. 10 seed against a No. 7 seed (39%), despite facing a much higher-ranked opponent. The 5/12 upset trend is a staple of March Madness bracket strategy, making No. 12 seeds prime candidates for early-round surprises.
No. 11 Seeds
If you’re looking for a deep Cinderella run, look no further than the No. 11 seed. Since 2011, a staggering fifteen No. 11 seeds have reached the Sweet 16, making them one of the most consistent double-digit seeds to advance beyond the first weekend. Even more remarkably, six No. 11 seeds have made it to the Final Four. This elite group of Cinderella teams includes 2024 NC State, 2021 UCLA, 2018 Loyola-Chicago, 2011 VCU, 2006 George Mason, and 1986 LSU. None of these teams made it to the championship game. The No. 11 seed is an undefeated 6-0 against No. 4, No. 7, and No. 9 seeds and am impressive 4-6 against No. 1 seeds.
No. 8/9 Seeds
While No. 8 and No. 9 seeds are evenly matched in the first round, their real danger lies in the second round. If an 8/9 winner can take down a No. 1 seed, their path to the Elite Eight becomes significantly easier. Historically, No. 8 and No. 9 seeds hold a 23-29 record against teams seeded No. 2-7. In particular, they have posted winning records against No. 4 and No. 5 seeds in the Sweet 16, proving that when they survive the early rounds, they can go much further than expected.
Final Takeaway: Which Seeds Deserve Your Attention?
A No. 15 seed upset is always fun to watch but nearly impossible to predict. For a more reliable first-round upset, the 5/12 matchup is your best bet. If you are hunting for deep Cinderella runs, No. 11 seeds have the strongest track record. If you want a high-risk, high-reward bracket pick keep an eye on No. 8 and No. 9 seeds poised to take down a No. 1 seed, especially with injuries plaguing both Duke and Houston. History shows that once an 8 or 9 seed knocks off a top team, their run may be far from over.