QuarterBack Rating Calculator
Definition: Quarterback rating is a measure of their performance in passing. It can also be known as Passer Rating, QB rating, and passing efficiency.
Quarterback rating is calculated with these categories:
 Yards gained per attempt
 Percentage of completions per attempt
 Touchdown passes per attempt
 Interceptions per attempt
This rating was created by a committee in the early 1970s, the committee was lead by Don Smith of the Pro Football Hall of Fame, Don Weiss of the National Football League and Seymour Siwoff of Elias Sports Bureau.
 To obtain a 2.375 percentage in interceptions, they would have to go a whole season without an interception
 To obtain a 2.375 percentage in touchdowns, a passer would have to get a percentage of 11.9
 To obtain a 2.375 percentage in yards per attempt, the passer has to have an average of 12.5 yards.
 To obtain a 2.375 percentage in completion percentage, a passer would have to complete 77.5 percent of their passes
 Percentage of completions per attempt forumla: (Completions / Attempts  .3) * 5
 Average yards gained per attempt formula: (Yards/Attempt 3) * .25
 Percentage of touchdown passes per attempt formula: (Touchdowns / Attempt) x 20
 Percentage of interceptions per attempt formula: 2.375  (Interceptions / Attempt * 25)
To make the rating more readable, it is converted into a scale of 100 with 158.3 being the highest possible rating when a passer has had a great season it is possible to get a score over a 100.
How to calculate a Quarterback's Rating
Let's use Tom Bradys 2017 season, he completed 385 of 581 passes for 4,577 yards, 32 touchdowns, 8 Interceptions.Our four calculations will be:
 Completion Percentage:
 We divide completed passes by attempts 385/581 = 0.6626 (66.26 Percent).
 We then subtract 0.3 from the completeion percentage: 0.6626  0.3 = 0.3626
 We then multiply by 5: 0.3626 X 5 = 1.813
 Important: if the result is 0 which means the completion rate is below 30 , 0 points are rewarded. If the completion rate is more then 77.5 percent, the result is 2.375

Average Yards Gained Per Attempt:
 We divide the yards by attemps (4,577/581) = 7.87 is the average yards per attempt
 Then subtract 3 yards from the yards per attempt: 7.87 3 = 4.87
 Now we multiply the result by 0.25: 4.87 X 0.25 = 1.2175
 Important: If the result is higher then 2.375 ( yards per attempts is higher then 12.5) the result is 2.375. When the result is less then 0 (yards per attempt is less then 3.0) the result is 0.

Touchdown Percentage:
 Touchdowns divided by attempts = 32/581 = 0.0550
 Then we multiply the result by 20: 0.0550 X 20 = 1.1
 The result is 1.1
 Important: If the result is higher then 2.375 ( touchdown percentage higher than 11.875), the result is 2.375

Interception Percentage:
 Interceptions divided by attempts (8/581) = 0.0137
 Multiply the interception percentage by 25: 0.0137 X 25 = 0.3425
 Subtract the result from 2.375: 2.375  0.3425 = 2.0325
 The result is 2.101
 Important: If the result is less then zero ( interception percentage higher then 9.5) the result is 0
 Now we sum the four results:
 1.2175 + 1.813 +1.1 + 2.0325 = 6.163.
 This is then divided by 6: 6.163 / 6 = 1.027
 Then multiplied by a hundred: 1.027 X 100 = 102.7
 The passer rating is 102.7
 Note this formula can be used for any player who has attempted at least one pass
How to Use QuarterBack Rating Calculator
QuarterBack Rating Calculator