Football QB Rating Calculator Formula

Understand the math behind the football qb rating calculator. Each variable explained with a worked example.

Use the Football QB Rating Calculator

Formulas Used

NFL Passer Rating

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

Completion Percentage

comp_pct = completions / attempts * 100

Yards per Attempt

yards_per_attempt = yards / attempts

Variables

VariableDescriptionDefault
completionsCompletions22
attemptsPass Attempts33
yardsPassing Yards280
touchdownsTouchdowns3
interceptionsInterceptions1
aDerived value= min(max((completions / attempts - 0.3) * 5, 0), 2.375)calculated
bDerived value= min(max((yards / attempts - 3) * 0.25, 0), 2.375)calculated
cDerived value= min(max(touchdowns / attempts * 20, 0), 2.375)calculated
dDerived value= min(max(2.375 - interceptions / attempts * 25, 0), 2.375)calculated

How It Works

NFL Passer Rating Formula

The NFL passer rating combines four component statistics, each capped at 2.375 and floored at 0, then averaged and scaled to a 0-158.3 range.

Components

1. Completion %: (COMP/ATT - 0.3) x 5 2. Yards/Attempt: (YDS/ATT - 3) x 0.25 3. TD %: TD/ATT x 20 4. INT %: 2.375 - INT/ATT x 25

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

A perfect rating is 158.3. Average in the modern NFL is around 88-92.

Worked Example

A QB goes 22/33 for 280 yards, 3 TDs, 1 INT.

completions = 22attempts = 33yards = 280touchdowns = 3interceptions = 1
  1. 01a = (22/33 - 0.3) x 5 = (0.667 - 0.3) x 5 = 1.833
  2. 02b = (280/33 - 3) x 0.25 = (8.48 - 3) x 0.25 = 1.371
  3. 03c = 3/33 x 20 = 1.818
  4. 04d = 2.375 - 1/33 x 25 = 2.375 - 0.758 = 1.617
  5. 05Rating = (1.833 + 1.371 + 1.818 + 1.617) / 6 x 100 = 110.7

Ready to run the numbers?

Open Football QB Rating Calculator