To estimate Sunday's take at the box office, it's all about the drop. Saturday is typically a bigger day at the movies than Sunday, so numbers naturally decline from Saturday to Sunday. Knowing the size of this change makes it fairly easy to predict how well a certain movie will do on Sunday, often before the first moviegoers settle in a seat at their local theater for the day's first matinee.
In general, ticket sales for any given movie decline between 25 percent and 30 percent from Saturday to Sunday [source: Mondello]. As an example, consider the percentage drop for the top 10 movies on the weekend of Aug. 15 through Aug. 17, 2014. The Saturday to Sunday drop in ticket sales for this period ranged from 23.3 to 37.4 percent, with an average drop of 28.7 percent [source: Box Office Mojo]. To estimate Sunday sales, simply multiply the numbers for Saturday by 65 to 75 percent. Add this figure to Friday and Saturday figures and you've got a weekend box office estimate.
Of course, predicting the weekend box office is anything but an exact science, and this 25 to 30 percent decrease doesn't always hold true. Variety estimates the weekend drop at a much wider 20 to 50 percent from even Friday to Saturday, though the studios and industry analysts can often estimate exactly where in that range that a given movie will fall based on factors such as demographics, genre, exit polls and release date [source: McClintock]. For example, a movie geared at teens will likely have a fairly large drop from Saturday to Sunday because teens tend to attend movies on Friday and Saturday nights. A G-rated film might have a smaller than usual drop thanks to Sunday daytime shows, which are popular with families [source: Mondello].
For an example of how studios use historical data and experience to pinpoint the potential drop and predict Sunday ticket sales, consider "Star Wars." Slate reported that "The Phantom Menance" had a Saturday-to-Sunday drop of 10 percent on its opening weekend, while "Attack of the Clones" came in at 22 percent. To predict the box office for "Star Wars," Fox assumed a drop of 16 percent based on the performance of the other films. Its guess was remarkably close and allowed it to accurately estimate the weekend box office for "Revenge of the Sith", which had a 15.9 percent drop from Saturday to Sunday [source: Snyder].