How to Calculate NFL Passer Rating and NCAA Passer Efficiency
The US National Football League (NFL) and Canadian Football League (CFL) rate passers on a scale of 0 to 158.3 using a formula that takes into account passing attempts, completions, interceptions, touchdown passes, and yards. The National Collegiate Athletic Association (NCAA) also rates passing efficiency using the same variables, but its formula and scale are different.
Any football player (not just quarterbacks) who has made at least one passing attempt can have a passing efficiency rating. Note that these ratings should not be confused with ESPN's Total Quarterback Rating, which is computed using a proprietary algorithm. The NFL and NCAA formulas are explained below; you can also use the calculator on the left.
NFL FormulaLet the variables a, c, i, t, and y represent attempts, completions, interceptions, touchdown passes, and yards respectively. Using these five variables, you compute four quantities P, Q, R, and S with the formulas
P = 5c/a - 1.5
Q = 2.375 - 25i/a
R = 20t/a
S = y/(4a) - 0.75
If any of P, Q, R, or S is less than 0, set the quantity to 0. Likewise, if any of the four is greater than 2.375, set the quantity equal to 2.375. This bounds each quantity between 0 and 2.375. With the adjusted values of P, Q, R, and S, evaluate the expression
100(P + Q + R + S)/6
to obtain the passer rating. Typically, the answer is rounded to the nearest tenth.
NCAA FormulaThe NCAA formula is easier because there is no intermediate step of computing quantities with upper and lower bounds. The expression for passing efficiency is simply
(100c - 200i + 330t + 8.4y)/a
The theoretical minimum is -731.6, which is attained when a = c, t = i = 0, and y = -99a. In other words, every pass is completed but results in a loss of 99 yards. The theoretical maximum is 1261.6, which is attained when a = c = t, i = 0, and y = 99a. In other words, every pass is completed for a touchdown and results in a 99-yard gain.
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