In Super Bowl history, the point spread has been, on average, just under a touchdown (6.7 points per game).
Here is the full breakdown of where each point spread in Super Bowl history has closed and which numbers have been been the most common.
The most common closing number in Super Bowl history is 3, with nine different Super Bowl's closing with a spread of exactly a field goal. In total, just over one-third of all Super Bowls, or 19 of 53 (35.8%), had a closing spread of 4 or smaller.
In those 19 Super Bowls that featured a short point spread (4 points or fewer), the line has never actually come into play at the end of the game. In fact, 26 Super Bowls have closed with a spread of 6 or less, and the line never came into play at the final whistle.
Let me explain…
In those 26 Super Bowl's (6 points or fewer), 13 underdogs won outright and 13 favorites won and covered the spread.
The lowest point spread for a favorite that won the Super Bowl straight-up but failed to cover the spread was 6.5 points in Super Bowl 10 and Super Bowl 43. In both of those games, the favorite won the game by 4 points, but failed to cover the 6.5-point spread.
In Super Bowl history, only six games had the straight-up winner not cover the spread and it hasn't happened since Super Bowl 43 between the Pittsburgh Steelers and Arizona Cardinals.
The Steelers were up, 20-7, and covering the 6.5-point spread more than five minutes into the fourth quarter. The Cardinals came storming back to take the lead on a 64-yard touchdown by Larry Fitzgerald, breaking the heart of Steelers backers. But Arizona left the Steelers too much time for Pittsburgh to win straight-up: Cue Santonio Holmes…
Over the past decade, favorites of 6 points or fewer in all playoff games outside the Super Bowl have gone 33-20 (62.3%) straight up and 25-26-2 (49%) against the spread.
Translation? Only eight favorites outside the Super Bowl have won as a favorite of 6 points or less, but failed to cover the spread.
Here's what this means for Super Bowl 54 between the Chiefs and 49ers: If you like San Francisco and think history will repeat itself, take the Niners on the moneyline. And if you like Kansas City? Laying the points — especially fewer than 3 points — isn't the worst thing in the world.
For what it's worth, this trend has also applies in college football, where bowl underdogs usually either win outright, or lose and fail to cover the spread. And since the BCS National Title Game was created in 1998, just three of 22 championships have seen the underdog lose but still cover.
