How Is Quarterback Rating Calculated

Professional NFL Passer Rating Calculator & Formula Guide

NFL Passer Rating Calculator

Enter stats to instantly calculate quarterback rating

What is Quarterback Rating?

The term “quarterback rating” most commonly refers to the NFL Passer Rating, a standard statistical metric used by the National Football League to evaluate the passing performance of a quarterback. Introduced in 1973, it is designed to condense a quarterback’s performance into a single number on a scale from 0 to 158.3.

Understanding how is quarterback rating calculated is essential for analysts, fantasy football players, and fans who want to move beyond simple yardage totals. Unlike ESPN’s proprietary “Total QBR,” the classic NFL Passer Rating relies solely on passing statistics: completions, attempts, yards, touchdowns, and interceptions. It does not account for rushing yards, sacks, or fumbles, which is a common point of confusion.

A perfect passer rating is 158.3, achieved by hitting specific statistical thresholds in all four calculation categories. Conversely, the lowest possible rating is 0.0. The formula is carefully weighted so that average performance yields a rating around 90-95 in the modern era, though inflation in passing stats has raised the league-wide average significantly over the decades.

How is Quarterback Rating Calculated: The Formula

The mathematical explanation of how is quarterback rating calculated involves four distinct steps. The formula breaks passing performance down into four components: completion percentage, yards per attempt, touchdown percentage, and interception percentage.

Each component is calculated separately and then capped (clamped) to ensure it falls between 0 and 2.375. This prevents one extreme stat from skewing the entire rating disproportionately.

The 4 Steps:

Let A = Attempts, C = Completions, Y = Yards, T = Touchdowns, I = Interceptions

Step A (Completion Component):
Value = ((C / A) – 0.3) × 5

Step B (Yardage Component):
Value = ((Y / A) – 3) × 0.25

Step C (Touchdown Component):
Value = (T / A) × 20

Step D (Interception Component):
Value = 2.375 – ((I / A) × 25)

*Note: If any result is < 0, set it to 0. If > 2.375, set it to 2.375.

Once you have the four values (let’s call them a, b, c, and d), the final calculation is:

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

Variable Definitions

Variable	Meaning	Perfect Threshold (Value = 2.375)
C / A	Completion Percentage	77.5% or higher
Y / A	Yards Per Attempt	12.5 yards or higher
T / A	Touchdown Percentage	11.875% or higher
I / A	Interception Percentage	0% (Value = 2.375 at 0 INTs)

Practical Examples

To fully grasp how is quarterback rating calculated, let’s look at two real-world scenarios.

Example 1: The Perfect Game

Imagine a quarterback with an incredible stat line:

• Attempts: 20
• Completions: 16 (80%)
• Yards: 250 (12.5 YPA)
• Touchdowns: 3 (15%)
• Interceptions: 0 (0%)

Calculation:
Step A: ((16/20) – 0.3) * 5 = 2.5 → Capped at 2.375
Step B: ((250/20) – 3) * 0.25 = 2.375 → Capped at 2.375
Step C: (3/20) * 20 = 3.0 → Capped at 2.375
Step D: 2.375 – ((0/20) * 25) = 2.375
Sum: 2.375 + 2.375 + 2.375 + 2.375 = 9.5
Result: (9.5 / 6) * 100 = 158.3 (Perfect Rating)

Example 2: A Struggling Performance

• Attempts: 40
• Completions: 20 (50%)
• Yards: 200 (5.0 YPA)
• Touchdowns: 0 (0%)
• Interceptions: 2 (5%)

Calculation:
Step A: ((0.5) – 0.3) * 5 = 1.00
Step B: ((5.0) – 3) * 0.25 = 0.50
Step C: (0) * 20 = 0.00
Step D: 2.375 – (0.05 * 25) = 1.125
Sum: 2.625
Result: (2.625 / 6) * 100 = 43.8

How to Use This Passer Rating Calculator

We designed this tool to simplify the complex math behind how is quarterback rating calculated. Follow these steps:

1. Enter Attempts (ATT): The total number of passes the QB threw. This must be greater than zero.
2. Enter Completions (COMP): The number of passes caught. This cannot be higher than the attempts.
3. Enter Yards (YDS): Total passing yards. Note that sack yardage is excluded in the NFL formula.
4. Enter Touchdowns (TD) & Interceptions (INT): The scoring plays and turnovers.
5. Analyze the Output: The calculator updates in real-time. Look at the “Formula Components” to see which area (accuracy, yardage, scoring, or security) is driving the rating up or down.

Key Factors That Affect Quarterback Rating

Several variables significantly influence the final number when exploring how is quarterback rating calculated.

• Volume vs. Efficiency: The formula rewards efficiency over volume. A QB who goes 10/10 for 150 yards will have a much higher rating than one who goes 25/50 for 300 yards, even though the second QB has more yards.
• Interception Penalties: Interceptions differ heavily. A high interception percentage can rapidly drag the “Step D” component to zero, significantly hurting the overall score.
• The “Cap” Effect: Because each component is capped at 2.375, “extra” performance doesn’t help. If a QB averages 15 yards per attempt, they get the same credit as one averaging 12.5 yards per attempt. This prevents outliers from breaking the scale.
• Sacks are Ignored: A major criticism of the classic rating is that it ignores sacks. A QB who takes 10 sacks but completes high-percentage passes will still have a high rating, despite hurting the team.
• Era Adjustments: A 90.0 rating was Pro Bowl level in 1980 but is considered average or below average in the 2020s due to rule changes favoring passing.
• Touchdown Weight: The formula heavily weights touchdowns. A short pass that results in a TD is statistically very valuable in the rating formula, sometimes more so than long drives that end in field goals.

Frequently Asked Questions (FAQ)

What is the highest possible quarterback rating?

The maximum possible NFL Passer Rating is 158.3. This requires a completion rate of 77.5%+, 12.5+ yards per attempt, 11.875%+ touchdown rate, and zero interceptions.

Why is the scale out of 158.3?

The number 158.3 is a result of the mathematical constants used in the formula (specifically the multipliers 5, 0.25, 20, and 25) combined with the normalization factor of dividing by 6 and multiplying by 100.

Does this calculator work for NCAA College Football?

No. The NCAA uses a completely different formula where the perfect rating is 1261.6 (technically unbounded). This calculator uses the strict NFL standard.

Is QBR the same as Passer Rating?

No. “Passer Rating” is the formula detailed here. “QBR” usually refers to ESPN’s Total QBR, which is a proprietary metric involving game context, clutch plays, and rushing value.

What is considered a “Good” rating?

In the modern NFL, a rating over 100 is considered excellent. A rating between 90 and 100 is good/average for a starter. Anything below 80 is generally considered poor performance.

How are spikes calculated?

In the NFL, spiking the ball to stop the clock counts as an incomplete pass, which slightly lowers the completion percentage component of the rating.

Can you have a negative quarterback rating?

No. The formula clamps individual components at zero. The lowest possible rating is 0.0.

Why don’t rushing yards count?

When the formula was created in 1973, quarterbacks were primarily passers. The metric was designed strictly to evaluate passing efficiency, not total offensive production.