A penalty is a broken rule, and the referee marks it by throwing a small yellow flag onto the field. The team at fault usually loses yards. Most penalties cost a fixed five, ten or fifteen yards, but one of them, pass interference, has no limit at all, which is why a single call can swing an entire game. I will start with the flag itself, then the calls you will see most, then the big one.
What the yellow flag means
When an official spots a foul, they throw a yellow flag to the ground and let the play finish. Only afterwards is the penalty announced and enforced. So the flag flying does not stop the action straight away, it marks that something is coming once the play is done.
Enforcing it usually means yards. If the offense breaks the rule, the ball is moved back towards its own end. If the defense breaks it, the ball is moved forward, and some defensive fouls also hand the offense an automatic first down (a fresh set of four attempts, no matter the distance). A few fouls carry a replay of the down instead, or as well.
One quirk worth knowing early: the team that was fouled can choose to decline the penalty. If the play worked out better for them than the penalty would, they simply wave it off and take the result of the play. You will hear the referee announce that a penalty was “declined”, and now you will know why.
The penalties you will see most
There are dozens of penalties in the rulebook, but you only meet a handful again and again. Over recent seasons, offensive holding and the false start are the only two that each make up more than a tenth of all flags thrown. Learn these and you will understand most of what you see:
| Penalty | Usual cost |
|---|---|
| Offensive holding | 10 yards |
| False start | 5 yards |
| Defensive holding | 5 yards and an automatic first down |
| Defensive offside | 5 yards |
| Unnecessary roughness | 15 yards |
| Delay of game | 5 yards |
| Offensive pass interference | 10 yards |
| Defensive pass interference | the spot of the foul, and an automatic first down |
A few of those in plain English. Offensive holding, the most-called penalty in the game, is a blocker illegally grabbing or hooking a defender to stop him getting past. A false start is an offensive player flinching or moving before the ball is snapped, which is why a noisy home crowd can be a real weapon. Defensive holding is a defender grabbing a receiver he is meant to be covering. Unnecessary roughness is a late or dangerous hit, and it costs the most of the common ones.
Notice the last row of the table. Every other penalty is a set number of yards. Pass interference is not, and that is the one worth understanding properly.
Pass interference: the one with no limit
Pass interference is when a player unfairly stops an opponent from catching a catchable pass, more than a yard beyond the line, before the ball arrives. Grabbing, shoving, hooking an arm, arriving early: if it wrecks the receiver’s chance at a ball he could have caught, it is interference. Both sides can commit it. On the offense it is called offensive pass interference (a flat ten yards). On the defense it is defensive pass interference, and this is where it gets serious.
In the NFL, defensive pass interference is a spot foul, governed by Rule 8, Section 5. That means the ball is moved to the exact spot where the foul happened, plus an automatic first down. NFL Football Operations puts it simply: DPI is “a spot foul, yielding an automatic first down”. There is no cap. If a defender interferes with a receiver forty-five yards downfield, that is a forty-five-yard penalty in a single play. If it happens in the end zone, the ball goes to the one-yard line.
This makes it the biggest swing in the game. In the 2017 season, of 303 defensive pass interference calls, 129 moved the ball more than fifteen yards, so better than a third of the time it was bigger than the largest fixed penalty on the board. It is worth knowing that this is a purely NFL severity: college football caps the same foul at fifteen yards, which is why you will hear NFL fans argue about it endlessly.
The no-call that changed the rule
The clearest proof of how much rides on one interference call is a call that was never made.
In the NFC Championship game on 20 January 2019, the New Orleans Saints and Los Angeles Rams were tied at twenty with under two minutes left. The Saints’ Drew Brees threw towards Tommylee Lewis, and the Rams’ Nickell Robey-Coleman hit him early, helmet to helmet and well before the ball arrived. It was clear interference. No flag came. The Saints, denied the first down that call would have given them, had to settle for a field goal, the Rams tied the game and won it in overtime, and Los Angeles went to the Super Bowl instead of New Orleans. Commissioner Roger Goodell later admitted the no-call should have been called.
The fallout changed the rulebook, briefly. For the 2019 season, the league made pass interference reviewable, both calls and non-calls, so a missed one like that could be corrected on replay. It did not work. Officials and coaches could not agree on what the replay standard even was, only 13 of 81 challenges succeeded all year, and the league dropped it again for 2020. So today we are back where we started: pass interference is a judgement call made in real time, it is not reviewable, and when it is missed there is no way to fix it. The one experiment aimed at that exact problem was tried and abandoned inside a single season.
That is the lesson of the penalty. It is the most powerful single call in the game, it turns on an official’s split-second judgement, and the league itself could not find a way to second-guess it.
Common questions
What is pass interference in the NFL?
Pass interference is when a player unfairly stops an opponent from catching a catchable pass, more than a yard beyond the line, before the ball arrives. On defense it is a spot foul: the ball goes to where the foul happened, with an automatic first down, so it has no yardage limit and can swing a game in one play.
What are the most common NFL penalties?
The two you will hear most are offensive holding, when a blocker illegally grabs a defender, and the false start, when an offensive player moves before the snap. Both cost yards and both happen several times a game. Defensive holding, offside and pass interference are close behind.
What is holding in American football?
Holding is grabbing or hooking a player who does not have the ball, to block or slow him illegally. Offensive holding costs the offense ten yards and is the most common penalty in the game. Defensive holding costs five yards and gives the other team an automatic first down.
Where to go next
- NFL Rules Decoded: how the whole game works.
- Scoring Decoded: the other reason the scoreboard moves.
- Replay & Challenges Decoded: what officials can and cannot review, including why pass interference is left off the list.
Want it straight from the source? Pass interference and every other foul are set out in the NFL’s official rulebook, and the league’s Video Rulebook shows real calls with clips.