Hong Life CalculatorsUnderstanding the NFL passer rating calculator — concept and principle
The NFL passer rating condenses a quarterback's passing line into one number between 0 and 158.3. It is the official efficiency measure used in NFL records and is reported in every box score, so it is the easiest way to compare passing games and seasons on the league's own scale.
How it is calculated
Four components are computed per attempt, and each is limited to the range 0 to 2.375:
- a (completion) = (CMP / ATT − 0.3) × 5.
- b (yards) = (YDS / ATT − 3) × 0.25.
- c (touchdowns) = (TD / ATT) × 20.
- d (interceptions) = 2.375 − (INT / ATT) × 25.
Passer rating = (a + b + c + d) / 6 × 100.
The caps are reached at a 77.5% completion rate, 12.5 yards per attempt, a touchdown on 11.875% of passes and zero interceptions; four maxed components give 9.5 / 6 × 100 = 158.3, a "perfect" rating.
The principle
The formula was designed so that each component equals about 1.0 for an average passer of the era it was built on and about 2.0 for an outstanding one, with 2.375 as the ceiling. Averaging four such scores and multiplying by 100/6 made an average rating close to 66.7. Because each component is a rate per attempt, the rating rewards efficiency rather than volume. The caps stop a single extreme category, such as a very high touchdown rate in a short game, from dominating the result. Since passing has become more efficient over the decades, today's averages sit well above the original design.
Worked example
- Inputs: 25 completions, 35 attempts, 300 yards, 2 TD, 1 INT.
- a = (25/35 − 0.3) × 5 = 2.0714.
- b = (300/35 − 3) × 0.25 = 1.3929.
- c = 2/35 × 20 = 1.1429; d = 2.375 − 1/35 × 25 = 1.6607.
- Sum = 6.2679; rating = 6.2679 / 6 × 100 = 104.46.
| Attempts | Passer rating |
|---|---|
| 8.75 | 118.75 |
| 17.5 | 133.0357143 |
| 26.2 | 123.8095238 |
| 35 | 104.4642857 |
| 43.8 | 83.98809524 |
| 52.5 | 70.33730159 |
| 70 | 53.27380952 |
How to read the result
In recent NFL seasons the league-wide passer rating has been around 90, so 100 or more is a very good game or season, and 110 or more over a full season is elite. A rating below about 75 is poor for a starter. The rating ignores sacks, rushing, fumbles and game situation, so pair it with other measures for a full picture.
Common mistakes
- Forgetting the 0 to 2.375 cap on each component, which produces impossible ratings above 158.3.
- Confusing the NFL rating with the NCAA passing efficiency formula, which uses a different scale.
- Comparing ratings across eras without considering the rise in league averages.
Frequently asked questions
What is a perfect passer rating?
158.3, reached when all four components hit the 2.375 cap.
Can passer rating be zero?
Yes, when all four components are at or below zero, for example with very low completion and yardage and several interceptions.
How is ESPN's QBR different?
QBR is a separate proprietary model that includes rushing, sacks and game context; it is not calculated from this formula.
Sources: NFL Record and Fact Book, National Football League (passer rating formula)