How is a passer rating calculated in football?
The NFL Formula
The NFL passer rating formula starts with four separate calculations: a = ((comp/att) - 0.3) * 5, b = ((yards/att) - 3) * 0.25, c = (TD/att) * 20, and d = 2.375 - ((INT/att) * 25). Each result is capped between 0 and 2.375. Then you add a, b, c, and d together, divide by 6, and multiply by 100. The final rating can range from 0 to 158.3 (a perfect score).
For example, if a quarterback completes 20 of 30 passes for 250 yards, 2 touchdowns, and 1 interception: a = ((20/30) - 0.3) * 5 = 1.833, b = ((250/30) - 3) * 0.25 = 1.333, c = (2/30) * 20 = 1.333, d = 2.375 - ((1/30) * 25) = 1.542. Sum = 6.041, divide by 6 = 1.007, multiply by 100 = 100.7 rating.
College and Other Variations
The NCAA uses a different formula that produces a wider range of scores, often exceeding 200. It is: (8.4 * yards) + (330 * touchdowns) + (100 * completions) - (200 * interceptions), all divided by attempts. This formula is not capped, so a perfect game can yield a rating above 300.
The CFL also has its own passer rating system, which is similar to the NFL's but uses slightly different constants. Always check which league or level you are looking at, because the numbers are not directly comparable.
Common mistakes
- Thinking a higher passer rating always means a better quarterback; it ignores rushing, sacks, and game context.
- Assuming the NFL and college formulas are the same; they produce very different numbers for the same performance.
