The NCAA men’s basketball tournament opened at a viewership high — again.
Thursday’s opening round coverage of the NCAA men’s basketball tournament averaged a combined 9.8 million viewers per window across CBS, TBS, TNT and truTV — up 6% from last year (9.1M) and the largest audience on record for the opening day of play. Between this year and last, Nielsen shifted to a new methodology that combines “Big Data” from smart TVs and set-top boxes with its traditional panel, generally boosting viewership.
That change is on top of Nielsen’s February 2025 expansion of its out-of-home viewing sample to cover 100 percent of markets in the lower 48 states. Shortly after that change, last year’s opening day of play also increased 6% to what was a then-record.
The last year without any notable Nielsen changes, 2024, the tournament opened with an average of 8.5 million — still the highest since 2015, but up only slightly from the prior year (8.4M). It would seem fair to suggest that the Nielsen changes have turbocharged what had previously been incremental growth for the tournament.
Full individual game figures were not immediately available, but primetime coverage featuring Michigan-Howard and VCU-North Carolina led the way with a combined 12.5 million — a record for a first round window and up 17% from last year, outside the range that would be explained by Nielsen’s methodological changes.
The two afternoon windows averaged a combined 8.0 and 9.8 million, both ranking as the highest for the first round of the tournament in their respective windows. The late window included Duke’s comeback win over 16 seed Siena, which averaged 5.43 million — the largest individual game audience of the day, surpassing Michigan-Howard (4.52M) and VCU-North Carolina (4.3M).
The full tournament is averaging a combined 9.3 million through Thursday, up 5% from last year and officially a new record. Note that the “First Four” counts as a single telecast window, grossing a combined 7.5 million across four games on truTV.
The tournament follows a regular season in which viewership increased 19% across all networks — including 12% on CBS — beyond the range that would be generally explained by methodology.
Duke and Michigan, which played in the top two games of Thursday, also played in eight of the ten most-watched games during the regular season.
