Passer Rating Explained: What the Formula Measures and Misses

By 4Football Staff · November 3, 2026 · 8 min read

The NFL passer rating runs from 0 to 158.3 and uses four simple inputs. See the formula, a worked example, why 158.3 is the ceiling, and where the number misleads.

Every box score prints a number next to a quarterback's name that looks like it was made up: 103.3, 87.6, 49.3. The scale seems odd, topping out at 158.3. A perfect game is not 100 and the average is not 50. Yet for decades this single number has been quoted in broadcasts, argued about in barbershops and used to rank quarterbacks in the record books.

Passer rating is not mysterious. It is a short formula with four inputs, and you can calculate it with a pocket calculator. Knowing how it works also shows you what it ignores, which is just as important if you are using it to judge a player.

Where the number comes from

The NFL adopted the passer rating in 1973. The league wanted a way to rank passers that was better than ranking by yardage or by completion percentage alone, either of which can be misleading. The formula was built from the statistics available in the official record at that time, and its settings were calibrated against the passing results of the 1960s so that a typical passer from that period would come out near the middle of the scale.

That calibration is why the numbers look strange today. The scale is not a percentage of anything. It is a weighted blend of four ratios, each scored from zero to a fixed maximum, then scaled so the total runs from 0 to 158.3.

The four ingredients

Passer rating uses only data from passing plays that are already in the box score:

1. Completion percentage. Completions divided by attempts.
2. Yards per attempt. Passing yards divided by attempts.
3. Touchdown percentage. Touchdown passes divided by attempts.
4. Interception percentage. Interceptions divided by attempts.

Notice what is missing: sacks, rushing, fumbles, down and distance, field position, the quality of the opponent, drops, throwaways and the score. We will come back to that.

The formula, step by step

Each of the four inputs is turned into a component score, with C for completions, ATT for attempts, YDS for passing yards, TD for touchdown passes and INT for interceptions.

Then two rules apply:

• Each component is limited to a minimum of 0 and a maximum of 2.375. If the calculation comes out below zero, it becomes zero. If it comes out above 2.375, it becomes 2.375.
• The rating is the sum of the four components, divided by 6, multiplied by 100.

rating = (a + b + c + d) ÷ 6 × 100

A worked example

Say a quarterback completes 25 of 35 passes for 290 yards, with 2 touchdowns and 1 interception. This is a made-up stat line.

1. a: 25 ÷ 35 = 0.7143. Subtract 0.30 to get 0.4143, then multiply by 5. Result: 2.0714.
2. b: 290 ÷ 35 = 8.2857. Subtract 3 to get 5.2857, then multiply by 0.25. Result: 1.3214.
3. c: 2 ÷ 35 = 0.0571, multiplied by 20. Result: 1.1429.
4. d: 1 ÷ 35 = 0.0286, multiplied by 25 gives 0.7143. Subtract from 2.375. Result: 1.6607.

The sum is 6.1964. Divide by 6 to get 1.0327, and multiply by 100 for a passer rating of 103.3. None of the components hit the cap, so the arithmetic is straightforward.

Why the scale ends at 158.3

The best possible value for each component is 2.375. Four perfect components total 9.5, divided by 6 is 1.5833, and times 100 gives 158.3. To earn a perfect rating in a game, a passer needs all of the following:

• A completion percentage of at least 77.5.
• At least 12.5 yards per attempt.
• A touchdown on at least 11.875 percent of attempts, which is roughly one touchdown every eight to nine throws.
• No interceptions.

A passer who needs only a couple of those can still be excellent. Each cap means that after a certain point extra production earns nothing. A quarterback who throws for 14 yards per attempt gets the same yardage credit as one who throws for 12.5.

The lowest possible rating is 0.0. That requires every component to be zero: a completion rate of 30 percent or lower, 3 yards per attempt or fewer, no touchdowns, and an interception rate of 9.5 percent or higher. A rating that low is rare over a full game. It does not mean the quarterback did nothing, only that the four inputs were as poor as the formula allows.

The 66.7 benchmark

If all four components equal exactly 1.0, the rating is 4 ÷ 6 × 100, or 66.7. The designers aimed for this to represent a typical passer of the 1960s, using the league's results from that decade as the standard. It is a historical reference point, not a modern average. Because passing has changed so much since, a rating of 66.7 would be below average in most modern seasons.

Reading the scale

A rating is not a grade. It is a number on a stretched scale, and an average value depends on the era. Some loose guidance that holds across time:

• Under 70 usually signals a poor passing day or a poor passing season.
• Around 80 to 90 is a solid, ordinary range.
• Over 100 is a strong day.
• Anything near the top of the scale in a single game usually comes from a short stat line with a lot of touchdowns and no interceptions.

For a season, a rating over 100 has been considered excellent by the standards of the era where it was earned. Do not compare ratings across decades without noting how much passing has changed. The league-wide passer rating has risen as rules, tactics and quarterback skill have developed. To judge a quarterback against his peers, look at where he ranks in his own season, not at the raw number.

The same game, different outcomes

Passer rating has surprising behavior because of its caps and weights. Consider three more hypothetical stat lines.

Quarterback B has a clearly poor game: 60 percent completions, six yards per attempt, no touchdowns and two interceptions. The rating of 49.3 reflects that. Quarterback C is more interesting. He threw no touchdowns, but he completed 75 percent of his passes with no interceptions, and the formula likes completion rate and clean play. His 90.6 is higher than many people would expect for a game without a touchdown.

This is the first lesson of passer rating: it rewards efficiency. A quarterback can score well by completing short, safe passes, while a deep thrower who takes risks may score lower even if the offense benefits.

What passer rating misses

The formula is a fair summary of four pieces of data. It is a poor summary of the whole of quarterback play. Here is what it leaves out.

Sacks

A sack is a pass play that ends in a loss, often because the quarterback held the ball or the protection failed. Passer rating ignores it. A sack is not an attempt, so it never enters the arithmetic, while a throwaway counts as an incompletion and lowers the rating a little. In other words, the formula can punish the safer choice more than the costlier one. For a better view, use net yards per attempt, which subtracts sack yardage. Our box score guide shows how.

Rushing

A quarterback who runs for first downs and touchdowns gets no credit. Modern offenses use their quarterbacks as runners, so passer rating undercounts a lot of the value.

Fumbles

Fumbles lost by a quarterback are not in the formula. A quarterback who protects the ball when passing but loses it often in the pocket looks better than he is.

Situation and context

A completion on third-and-12 that gains 5 yards counts as a completion and 5 yards, even though the offense punts. A short pass on first down that gains 5 yards counts the same. Passer rating has no sense of down, distance, field position, score or time remaining. It cannot tell a pass that kept a drive alive from one that was irrelevant.

Receiver and protection quality

A quarterback throwing to excellent receivers behind a strong offensive line will post better numbers than the same player in a worse situation. Yards after the catch inflate yards per attempt even though the receiver did the work. Dropped passes lower completion percentage even though the throw was fine.

The caps

Because each component is capped, performance beyond the ceiling is invisible. That affects only the very best games, but it also means the formula compresses differences at the top.

Defense and opponent

Passer rating does not adjust for how good the defense was. Throwing against a weak secondary and a strong one produce the same arithmetic.

College uses a different formula

If you follow college football, note that the NCAA uses its own passing efficiency formula, which is not the NFL's. It is:

(8.4 × yards + 330 × touchdowns + 100 × completions − 200 × interceptions) ÷ attempts

There is no cap, so college ratings can go well above 158.3. The same hypothetical line from our worked example, 25 of 35 for 290 yards with 2 touchdowns and 1 interception, comes to about 154.2 under the college formula, compared with 103.3 under the NFL's. The numbers are not directly comparable. If you see a college quarterback's efficiency rating above 160 and an NFL quarterback's rating of 105, they are not on the same scale. Our college section uses the standard statistics for its level.

Other levels, including high school and youth football, rarely track the rating at all.

Alternatives and companions

No single number replaces judgment, but several other measures cover some of the gaps.

• Net yards per attempt and its adjusted cousin include sacks. The adjusted version also rewards touchdowns and penalizes interceptions.
• Total QBR. A proprietary metric published by ESPN, scored from 0 to 100, that tries to include rushing, sacks, fumbles and the context of each play. Its inputs are not fully public.
• Success rate and expected points added. Play-by-play measures of how often a play helps the offense and by how much. Our advanced stats primer walks through them.
• Completion percentage over expected. A tracking-data measure of how a quarterback performs compared with the difficulty of his throws.

Each of these has its own limits. The wise approach is to compare a few. If passer rating, net yards per attempt and a play-based measure all agree, you can be fairly confident. If they disagree, the disagreement itself is useful: it points to sacks, rushing, drops or situation as the reason.

Using passer rating well

• Use it to compare quarterbacks within the same season or era, not across decades.
• Check sample size. A rating over 30 attempts means more than one over 8.
• Pair it with sacks, rushing and turnovers.
• Remember that the league sets a minimum number of attempts per scheduled game for a passer to qualify for rating leaderboards, so a backup with a few perfect throws is not listed as the league leader.
• Treat huge swings as information about volume and luck as well as skill.

You can see the stat lines behind the ratings on our league leaders page, and each player page lists a passer's full game log. For more on how quarterbacks are valued, read about why quarterbacks are paid what they are paid.

The short version

• Passer rating blends completion percentage, yards per attempt, touchdown rate and interception rate.
• Each component is capped between 0 and 2.375, which is why the scale runs from 0 to 158.3.
• The formula is (a + b + c + d) ÷ 6 × 100, and you can compute it by hand.
• It was calibrated to 1960s passing, so 66.7 is a historical benchmark rather than today's average.
• It ignores sacks, rushing, fumbles, down and distance, and the quality of the supporting cast.
• College football uses a different, uncapped formula, so the two cannot be compared directly.
• Use it with other measures rather than as a verdict.