How To Calculate The NFL’s Passer Rating Formula

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I reveal the formula behind a much-maligned statistic.


Each year at this time I run this column about the NFL’s Passer Rating Formula, slightly altered to reflect current trends. Because Halloween is coming up, we ask you not to be scared of the complicated process that goes into it. But because I get plenty of questions about this statistic–and year-round, I might add–I like to haul it out annually.

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Let’s face it, it’s a scary time of year. It’s not just because Halloween is coming up–although that certainly doesn’t help. Decorations, candy, costumes and other ancillary items make this fall observance more expensive than ever.

What? You thought we meant ghosts, goblins, and blood? That’s mere child’s play, the stuff of healthy, youthful role-playing fantasy, no matter what the overzealous, politically-correct crowd says.

No! What makes this portion of the calendar most perilous are the dangling playoff fortunes of the many NFL teams that may think they are contenders, but truly aren’t.

What leads to such uncertainty? The leaguewide passing-game explosion, that’s what. Just as baseball observers have endlessly complained that expansion has diluted the amount of quality pitching throughout the sport, the same could be said of the depth of NFL defenses falling victim to the gaudy passing numbers offenses are posting.

Courtesy: Kirby Lee-USA TODAY Sports

In 2008, there was but one quarterback — the Chargers’ Philip Rivers — who notched a season-long passer rating higher than 100. Eight years later, there were five quarterbacks with appreciable playing time who surpassed that figure. Twelve additional signal-callers broke the 90-barrier.

With 158.3 denoting a perfect passer rating, it means–more so than at any previous point in history–that quarterbacks are closer to perfect than they’ve ever been.

In recent years, ESPN has unveiled the QBR, a system that’s weighted so that 100 is the number for a perfect rating. But since the league does not recognize that system as official, here we’ll go with the current system.

We could be heading for a return to the days when teams would be facing future Hall of Fame quarterbacks every week, concerned — if not downright fearful — that they would be victimized by the tenacity of a Roger Staubach or John Unitas; the arm of a Sammy Baugh or Bart Starr; or the accuracy of a Len Dawson or Otto Graham.

None of the above QBs, or any of their contemporaries, seem to care much for statistics, such as the modern-day implementation of the passer rating (1973).

Today, this oft-maligned statistic shouldn’t be called a “quarterback” rating because it doesn’t measure leadership and other intangibles unique to the position.

But it means just about everything for fans, coaches, and general managers who evaluate talent and need an all-encompassing number to see where someone stands.

For years, many have asked me how a passer rating is compiled. Well, it’s a convoluted process requiring an analytical mind, strong batteries in the calculator, and a lot of patience.

If you’re ready to take a trip into this shadowy, haunted world, here we go …. And try not to scream!

1. First, it’s important to know that the passer rating is compiled of four main stats: percentage of completions, touchdown passes, interceptions per attempt and average gain per attempt. The highest number a passer can achieve in these four categories — through the formula, you will see in a few moments — is 2.375.

2. Subtract 30 from the completion percentage and multiply that number by .05. If you get a number less than zero, then the number for this section is zero. If the result is more than 2.375, then that is the number assigned. The league likes to use Peyton Manning’s 2004 season as an example in these matters. Manning completed 67.6 percent of his passes that year. When the above formula is applied, the result is 1.880. Keep that number handy, for it will be needed later.

Courtesy: Getty Images

3. Subtract 3 yards from the average yards per pass and multiply that by .25. In 2004, Manning threw for 4,557 yards on 497 attempts. That’s 9.17 yards per attempt, which — when Step 3 is applied — turns into 1.543. Again, that number will become more important in a few minutes.

4. Multiply the touchdown percentage by 0.2. As in Step 2, if the result is greater than 2.375, then that is the number assigned. But that wasn’t the case with Manning, whose biggest year ever featured 49 touchdown passes out of 497 throws. The touchdown percentage was 9.86 percent, which turns into 1.972.

5. Multiply the interception percentage by 0.25 and subtract the resulting number from 2.375. If the result is less than zero, then zero is the resulting number for this step. Manning threw 10 interceptions out of his 497 throws for a 2.01 percent reading. Applying Step 5, the result is 1.872.

6. Take the resulting numbers from Steps 2 through 5 and add them together. You will get 7.267.

7. Then — if your brain hasn’t exploded by now — divide the Step 6 result by six and multiply that result by 100. You should have come up with Manning’s passer rating for 2004, a gaudy 121.1.

We hope you’ve now learned not to be afraid of the passer rating. But if you’re still fearful of quarterbacks as good as Manning was and Tom Brady, we can’t help you there.

After all, it’s a scary time of year.

About Joe Platania

Veteran Ravens correspondent Joe Platania is in his 45th year in sports media (including two CFL seasons when Batlimore had a CFL team) in a career that extends across parts of six decades. Platania covers sports with insight, humor, and a highly prescient eye, and that is why he has made his mark on television, radio, print, online, and in the podcast world. He can be heard frequently on WJZ-FM’s “Vinny And Haynie” show, alongside ex-Washington general manager Vinny Cerrato and Bob Haynie. A former longtime member in good standing of the National Sportscasters and Sportswriters Association and the Pro Football Writers of America, Platania manned the CFL Stallions beat for The Avenue Newspaper Group of Essex (1994 and ’95) and the Ravens beat since the team’s inception — one of only three local writers to do so — for PressBox, The Avenue, and other local publications and radio stations. A sought-after contributor and host on talk radio and TV, he made numerous appearances on “Inside PressBox” (10:30 a.m. Sundays), and he was heard weekly for eight seasons on the “Purple Pride Report,” WQLL-AM (1370). He has also appeared on WMAR-TV’s “Good Morning Maryland” (2009), Comcast SportsNet’s “Washington Post Live” (2004-06), and WJZ-TV’s “Football Talk” postgame show — with legend Marty Bass (2002-04). Platania is the only sports journalist in Maryland history to have been a finalist for both the annual Sportscaster of the Year award (1998, which he won) and Sportswriter of the Year (2010). He is also a four-time Maryland-Delaware-District of Columbia Press Association award winner. Platania is a graduate of St. Joseph’s (Cockeysville), Calvert Hall College High School, and Towson University, where he earned a degree in Mass Communications. He lives in Cockeysville, MD.



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