Stat Used To Calculate A Qb\’s Passer Rating

Calculate QB Passer Rating

What is Passer Rating?

The Passer Rating (often called QB Rating or Quarterback Rating in the NFL) is a measure used to assess the performance of quarterbacks or other passers in American football and Canadian football. It was developed by the NFL in 1971 and officially adopted in 1973. The formula combines four key passing statistics: completion percentage, yards per attempt, touchdown percentage, and interception percentage into a single number.

The Passer Rating is designed to provide a standardized way to compare the passing efficiency of quarterbacks across different games, seasons, and eras, although its effectiveness for the latter is sometimes debated. It is used by the NFL, CFL, fans, analysts, and media to evaluate quarterback play. The highest possible Passer Rating is 158.3, and the lowest is 0.

Common misconceptions include believing it’s the only measure of a QB’s value (it ignores rushing, leadership, etc.) or confusing it with ESPN’s Total QBR, which is a different, more complex metric incorporating more factors.

Passer Rating Formula and Mathematical Explanation

The NFL Passer Rating is calculated using four components derived from a quarterback’s performance:

1. Completion Percentage Component (a): Based on completions per attempt.
2. Yards Per Attempt Component (b): Based on passing yards per attempt.
3. Touchdown Percentage Component (c): Based on touchdowns per attempt.
4. Interception Percentage Component (d): Based on interceptions per attempt.

The formulas for these components are:

• `a = ((COMP / ATT) – 0.3) * 5`
• `b = ((YDS / ATT) – 3) * 0.25`
• `c = (TD / ATT) * 20`
• `d = 2.375 – ((INT / ATT) * 25)`

Each component (a, b, c, d) is capped at a maximum value of 2.375 and floored at a minimum of 0. If any component calculation results in a value greater than 2.375, it is set to 2.375. If it’s less than 0, it is set to 0.

Once the four components are calculated and capped/floored, the final Passer Rating is determined by:

Passer Rating = ((a + b + c + d) / 6) * 100

The maximum Passer Rating is 158.3 (when a, b, c, and d all equal 2.375), and the minimum is 0.

Variables Used in Passer Rating Calculation

Variable	Meaning	Unit	Typical Range
ATT	Pass Attempts	Number	1 – 60+ (per game)
COMP	Completions	Number	0 – ATT
YDS	Passing Yards	Yards	-10 – 500+ (per game)
TD	Touchdown Passes	Number	0 – 7+ (per game)
INT	Interceptions	Number	0 – 7+ (per game)
a, b, c, d	Intermediate Components	Number	0 – 2.375

Practical Examples (Real-World Use Cases)

Example 1: Efficient Game

A quarterback has the following stats in a game:

• Attempts (ATT): 35
• Completions (COMP): 25
• Yards (YDS): 310
• Touchdowns (TD): 3
• Interceptions (INT): 0

Using the calculator or formulas:

• a = ((25/35) – 0.3) * 5 = (0.7143 – 0.3) * 5 = 2.0715
• b = ((310/35) – 3) * 0.25 = (8.8571 – 3) * 0.25 = 1.4643
• c = (3/35) * 20 = 0.0857 * 20 = 1.7143
• d = 2.375 – ((0/35) * 25) = 2.375

Passer Rating = ((2.0715 + 1.4643 + 1.7143 + 2.375) / 6) * 100 = (7.6251 / 6) * 100 = 127.1

This results in a very high Passer Rating of 127.1, reflecting an efficient performance with good completion percentage, yards per attempt, touchdown rate, and no interceptions.

Example 2: Struggling Game

Another quarterback has a tougher game:

• Attempts (ATT): 40
• Completions (COMP): 18
• Yards (YDS): 190
• Touchdowns (TD): 1
• Interceptions (INT): 3

Calculations:

• a = ((18/40) – 0.3) * 5 = (0.45 – 0.3) * 5 = 0.75
• b = ((190/40) – 3) * 0.25 = (4.75 – 3) * 0.25 = 0.4375
• c = (1/40) * 20 = 0.025 * 20 = 0.5
• d = 2.375 – ((3/40) * 25) = 2.375 – (0.075 * 25) = 2.375 – 1.875 = 0.5

Passer Rating = ((0.75 + 0.4375 + 0.5 + 0.5) / 6) * 100 = (2.1875 / 6) * 100 = 36.5

This results in a low Passer Rating of 36.5, indicating struggles with accuracy, low yards per attempt, and a high interception rate relative to touchdowns.

How to Use This Passer Rating Calculator

1. Enter Pass Attempts (ATT): Input the total number of times the quarterback attempted a pass.
2. Enter Completions (COMP): Input the number of passes that were successfully caught by a receiver. This cannot be more than the attempts.
3. Enter Passing Yards (YDS): Input the total yards gained from completed passes. This can be negative if yards were lost.
4. Enter Touchdown Passes (TD): Input the number of passes that resulted in a touchdown.
5. Enter Interceptions (INT): Input the number of passes that were intercepted by the defense. This cannot be more than the attempts.
6. Calculate: Click the “Calculate” button or observe the results update as you type if real-time updates are enabled. The calculator will validate inputs and show errors if necessary.
7. Read Results: The primary result is the Passer Rating, displayed prominently. You’ll also see the intermediate components (a, b, c, d) that contribute to the final rating, along with a table and chart visualizing these components.
8. Reset: Use the “Reset” button to clear the fields to their default values for a new calculation.
9. Copy Results: Use the “Copy Results” button to copy the main rating and components to your clipboard.

The Passer Rating gives you a standardized score to evaluate a QB’s passing efficiency in a game or over a season. Higher numbers generally indicate better performance, but context (like opponent strength, game situation) is also important.

Key Factors That Affect Passer Rating Results

Several factors directly influence a quarterback’s Passer Rating:

• Completion Percentage (COMP/ATT): A higher completion percentage directly increases component ‘a’. Accuracy and good decision-making lead to more completions and a better Passer Rating.
• Yards Per Attempt (YDS/ATT): More yards per attempt boost component ‘b’. This reflects the ability to complete passes downfield or get yards after the catch, contributing to a higher Passer Rating.
• Touchdown Percentage (TD/ATT): Throwing more touchdowns per attempt increases component ‘c’. Finishing drives with touchdown passes is heavily rewarded in the Passer Rating formula.
• Interception Percentage (INT/ATT): Fewer interceptions per attempt increase component ‘d’ (as interceptions reduce it). Ball security and avoiding turnovers are crucial for a good Passer Rating.
• Number of Attempts (ATT): While not directly in the final formula after components are calculated, the number of attempts is the denominator for all percentage-based components. A very small number of attempts can lead to volatile and less meaningful ratings. More attempts provide a more stable and reliable Passer Rating.
• Game Context (Indirect): Factors like opponent quality, weather, and offensive line play can indirectly affect the stats that go into the Passer Rating, thus influencing the result. However, the formula itself only considers the raw stats.

Understanding how these factors influence the football metrics like Passer Rating helps in evaluating QB performance more deeply.

Frequently Asked Questions (FAQ)

What is the highest possible Passer Rating?

The highest possible Passer Rating is 158.3. This is achieved when all four components (a, b, c, d) reach their maximum value of 2.375.

What is the lowest possible Passer Rating?

The lowest possible Passer Rating is 0. This happens when all four components are at their minimum value of 0.

Is a Passer Rating of 100 good?

Yes, a Passer Rating of 100 or above is generally considered very good to excellent for a season or game. League average usually hovers in the high 80s or low 90s.

How is Passer Rating different from Total QBR?

Passer Rating is a formula based only on passing stats (completions, attempts, yards, TDs, INTs). ESPN’s Total QBR is a more complex metric that includes a QB’s rushing contributions, sacks, fumbles, strength of opponent, and game situation (“clutch” factor), scaled from 0-100. Learn more about understanding QBR vs Passer Rating.

Can a quarterback have a perfect Passer Rating?

Yes, a QB can achieve a perfect Passer Rating of 158.3 in a game, although it’s rare. It requires high completion percentage, yards per attempt, touchdown rate, and no interceptions, such that all four components hit 2.375 (e.g., minimum 70.8% completions, 12.5 yards/attempt, 11.8% TD rate, 0 INTs, though the exact minimums interact).

Does Passer Rating account for rushing yards or sacks?

No, the traditional NFL Passer Rating formula does not include any rushing statistics or the negative impact of sacks (other than reducing the number of attempts without yards gained if it was a pass play). It strictly measures passing efficiency.

Why is there a cap on the components?

The caps (2.375) and floors (0) on components ‘a’, ‘b’, ‘c’, and ‘d’ prevent extreme outlier performances on a small number of attempts from skewing the Passer Rating too dramatically and keep it within a defined range leading to the 158.3 max.

Is Passer Rating the best way to evaluate a QB?

Passer Rating is a useful tool for measuring passing efficiency but is not a complete measure of a quarterback’s overall value. It doesn’t include rushing, leadership, or context. Other metrics like advanced NFL stats and Total QBR offer different perspectives on NFL player performance.

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