Passer Rating Explained: How to Calculate It

Every passer rating comes from four inputs off the stat sheet: completions, passing yards, touchdowns, and interceptions, all divided by pass attempts. Nothing else feeds the number. Sacks, rushing, and fumbles stay out of it.

Each input becomes its own component, labeled a through d. Component a is completion percentage. Component b is yards per attempt. Component c is touchdown rate. Component d is interception rate, and it is the only one that starts high and drops as the number gets worse. Average the four, scale the result, and you have the rating.

Run the four formulas below in order. Completion rate and yardage reward volume and efficiency. Touchdown rate rewards finishing drives. Interception rate is scored in reverse: it begins at the maximum and every pick chips away at it.

The catch is the cap. No single component can go below 0 or above 2.375. If a quarterback completes 90 percent of his passes, component a still stops at 2.375. That ceiling is what keeps one monster stat from breaking the scale, and it is why the math has a hard perfect score.

Component b uses yards per attempt, subtracts a baseline of 3, and scales it down. Component c turns touchdown rate into points on the scale. Component d starts at the maximum of 2.375 and subtracts a heavy penalty for every interception, which is why picks sink a rating fast.

Clamp each one the same way: floor of 0, ceiling of 2.375. A clean game with zero interceptions leaves component d sitting at its full 2.375.

Add the four capped components, divide by 6, and multiply by 100. That is the final passer rating. Because each component maxes at 2.375, the highest possible sum is 9.5, and 9.5 divided by 6 times 100 lands on 158.3. That is the perfect rating.

Read it like this: around 90 is good, 100-plus is excellent, and anything near the ceiling means the quarterback was close to flawless. A rating in the 70s or below means the completion rate, yardage, or turnovers dragged him down.

Statside computes passer rating automatically the moment you log a completion, attempt, touchdown, or interception, so you never touch this math during a game. It also runs season leaderboards with a minimum-attempts threshold so one perfect 4-for-4 quarter does not top a full season of work.

For reference, the remaining two formulas are the touchdown and interception components. Touchdown rate multiplies by 20; interception rate subtracts 25 from the 2.375 starting point, the steepest penalty in the whole calculation.

So what is a good passer rating? Roughly 90 and up is solid starter play. Cross 100 and you are in excellent territory, the range top quarterbacks live in over a season. The 120s and up usually mean a big, clean game with multiple scores and no giveaways. The perfect 158.3 requires completing at least 77.5 percent, averaging at least 12.5 yards per attempt, throwing a touchdown on at least 11.875 percent of attempts, and zero interceptions, all at once.

College football skips the caps entirely. NCAA passer efficiency uses one straight-line formula with no clamps and no averaging, which is why its numbers run on a wider scale and can climb well past 158.3 or dip below zero.

It weights the same four categories: yards, touchdowns, completions, and interceptions, all over attempts. Same 25-of-35, 300-yard, 3-touchdown, 1-interception line scores 166.0 here. The lack of a ceiling is the whole difference: one huge game can spike an NCAA rating in a way the NFL cap would flatten.