NFL Clock Rules: When the Game Clock Stops and Restarts
NFL clock rules explained: what stops the game clock under Rule 4, when it restarts, why a first down keeps it running and how the 10-second runoff works.
By CricketTaken EditorialPublished NFL Rules27 min read
- Regulation length
- 4 x 15 minutes
- Out-of-bounds stops until the snap
- Last 5:00 of the 2nd half
- Runoff for a time-saving foul
- 10 seconds
- Halftime intermission
- 13 minutes
The NFL clock rules sit in Rule 4 of the league's rulebook, and the heart of them is a list of ten events. The game clock stops when a forward pass is incomplete, when the ball goes out of bounds, when it is dead on or behind a goal line, at the end of a down with a foul or a change of possession, at the end of a kick down, when the referee signals the two-minute warning, and whenever an official calls time. A first down is not on the list. Neither is a sack, nor a tackle in the field of play.
When the clock restarts depends on why it stopped. After an incompletion, a timeout or a change of possession it waits for the next snap. After most out-of-bounds plays and most penalties it restarts on the referee's ready-for-play signal, which can be ten seconds later or less. Late in each half the book tightens: after the two-minute warning of the first half and inside the last five minutes of the second, a runner who steps out stops the clock until the snap, and an offense that saves time with a foul has 10 seconds taken off the clock as well.
Take a running back who gains eight yards and is shoved out at the sideline. With 5:30 left in the fourth quarter, that stops the clock for as long as it takes the umpire to spot the ball. With 4:58 left, it stops it for the whole 40-second interval before the next snap. Across a drive, the difference can be worth more than a minute.
What stops an NFL game clock under Rule 4
Section 4 of Rule 4 is addressed to the game clock operator, and it tells him to stop the clock on a signal from any official or "upon the operator's own positive knowledge." Then come the ten situations. Most viewers could name four or five of them. The rest are the ones that produce arguments.
| Rule 4-4 item | When the clock stops |
|---|---|
| (a) | At the end of a down with a free kick or a fair catch kick |
| (b) | When the kicking team recovers a scrimmage kick beyond the line of scrimmage |
| (c) | When the ball is out of bounds |
| (d) | When the ball is dead on or behind a goal line |
| (e) | At the end of a down during which a foul occurs |
| (f) | When a forward pass is incomplete |
| (g) | At the time of a foul for which the ball stays dead or is dead immediately |
| (h) | When the referee signals the two-minute warning |
| (i) | When a down ends during or after which there is a change of possession |
| (j) | When any official signals a timeout for any other reason |
Item (d) is the one that covers scores. A touchdown is a ball dead behind the goal line, so is a touchback, so is a safety. Nobody needs a separate clause for each.
Item (e) is broader than it looks. The clock stops at the end of a down in which any foul occurs, whether or not the penalty is eventually accepted. The officials need time to sort out the flag, and the clock should not be running while they do. What happens after that is a separate question, answered in the restart provisions further down the page.
Item (g) handles the pre-snap fouls: a false start, encroachment, a delay of game. The ball never becomes live, so the clock stops at the moment of the foul.
Item (j) is the catch-all, and it carries more weight than its length suggests. A referee's timeout for a measurement goes through it. So does a stoppage for an injured player, a pile that will not unstack or a replacement ball. The referee's power to stop the clock "when playing time is being consumed because of an unintentional delay" is spelled out in Section 5, and the book lists seven typical causes, from a chain-crew injury to an officials' conference.
Stopping and starting are written in different places
Section 4 says when the clock stops. Section 3 says when it starts again, and the second answer is where all the strategy lives. The default in Article 2 of Section 3 is plain: after any timeout, which in the rulebook's vocabulary means any stoppage of the clock, the game clock starts on the next snap. Then follows a list of exceptions, and most of the game is played inside them.
Out of bounds is only a pause until the referee signals
A runner who steps out of bounds stops the clock. For most of an NFL game that stoppage lasts only as long as it takes to retrieve the ball, set it at the inbounds spot and get the officials into position. Article 2(a) of Rule 4, Section 3 says the clock "starts on the Referee's signal that a ball has been returned to play." The referee sounds his whistle and twirls his arm, and the operator starts the clock. Often the offense has not even broken the huddle.
There are three exceptions, and in each of them the clock waits for the snap instead.
- After a change of possession, such as an interception returned out of bounds.
- After the two-minute warning of the first half.
- Inside the last five minutes of the second half.
Those last two windows are not symmetrical, and the asymmetry is deliberate. The first half gets two minutes of the stricter treatment and the second half gets five, because the end of a game matters more than the end of a half and a trailing team needs a way to save time that does not cost it a timeout. Regular-season overtime is played under the fourth-quarter timing provisions, so the five-minute window applies at the end of that period too.
- Runner steps outThe ball is dead and the game clock operator stops the clock under Rule 4-4(c).
- Ball is spottedThe ball crew and the umpire set a ball at the inbounds spot. The 40-second play clock is already running.
- Outside the late windowsThe referee signals the ball ready for play and the game clock starts again before the snap.
- Inside the late windowsThe game clock stays stopped and starts only when the ball is next snapped.
- Change of possessionIf the ball changed hands on the play, the clock waits for the snap at any point in the game.
Rule 4, Sections 3 and 4 of the NFL rulebook. The late windows are after the two-minute warning of the first half and inside the last five minutes of the second half.
The fumble and the backward pass
Article 2(f) adds a variation. If a fumble or a backward pass goes out of bounds, the clock starts on the referee's signal that a ball has been returned to the field, with no late-half exception. The difference matters only at the margins, and after the two-minute warning a backward pass thrown out of bounds is treated as an illegal attempt to save time, discussed below.
Why the pause is shorter than viewers think
The ready signal can come quickly. On a run that ends near the offense's own sideline, the ball is back on the hash in a few seconds and the clock is running again while the coordinator is still on the radio. Before the five-minute mark, then, a leading team loses very little by getting pushed out. Inside it, the same play is a gift to the defense, and a ball carrier protecting a lead is coached to cut back inside and take the tackle.
Why a first down does not stop the clock in the NFL
Nothing in the NFL's list of ten mentions a first down. When a runner is tackled in the field of play beyond the line to gain, the chain crew moves the sticks while the 40-second play clock runs, and the game clock runs with it.
The only time a first down appears to stop the professional clock is when the officials need a measurement. A referee's timeout for "the possibility of a measurement for a first down" is the first item on the book's list of reasons to stop play. The chains come in, the ball is measured, and when the referee is finished the clock starts as if his timeout had never happened. Under Section 5, Article 5, the play clock also resumes with whatever it showed when he stopped it.
Where the belief comes from
College football. For decades the NCAA stopped the clock on every first down so the chain crew could reset, then restarted it on the referee's signal. A generation of viewers grew up watching Saturday games in which a first down was a brief stoppage, then watched Sunday games in which it was not, and the two habits blurred.
The NCAA changed its rule for the 2023 season, partly to shorten games. The college clock now keeps running after a first down except in the last two minutes of each half, when it still stops briefly for the chains. So a first down still stops a college clock late in a half, and the confusion has not fully gone away. The other gaps between the two rulebooks are collected in our guide to every difference between college football and NFL rules.
What a first down does change
Strategically, plenty. A first down resets the number of snaps an offense can run before it must give the ball up, and for a team running out the clock that matters far more than any stoppage would. Each new snap can be preceded by a full play clock.
When the clock starts after a penalty
The general rule is one sentence in Article 2(e) of Section 3. If the clock is stopped before or after a down for a foul by either team, then once the penalty is enforced or declined "the game clock will start as if the foul had not occurred."
That phrasing does a lot of work. A holding foul on a running play that ended in the field of play: the clock would have kept running, so after enforcement it starts on the ready-for-play signal. Pass interference on an incompletion: the clock would have stopped anyway, so it starts on the snap. The penalty itself is never the reason the clock stays stopped.
Then the exceptions. The clock waits for the snap after a foul if:
| Article 2(e) exception | What it covers |
|---|---|
| (1) | Any foul after the two-minute warning of the first half |
| (2) | Any foul inside the last five minutes of the second half |
| (3) | An offensive foul in the fourth period or regular-season overtime, after the ball is ready, that stops the clock before a snap |
| (4) | Two successive delay-of-game fouls by the offense in the same down while time is in |
| (5) | Any case where a specific rule says otherwise |
The first two mirror the out-of-bounds windows. The third is the interesting one.
The fourth-quarter false start
Picture an offense ahead by four points with nine minutes left. Its quarterback could, in theory, commit a false start on purpose. The penalty costs five yards. Without exception (3), the clock would start again on the ready signal and the play clock would be reset to 25, so the offense would have burned some of the game clock and handed itself a fresh count at the price of five yards. The rulebook closes that route by making the clock wait for the snap after any pre-snap offensive foul in the fourth quarter, which means the foul burns nothing.
Exception (4) does the same job for the team that takes two delay penalties in a row while the clock is running.
There is also a broader prohibition in Rule 12. A team that commits multiple fouls on the same down to run time off the clock is penalized 15 yards, the clock is reset to the time of the snap, and it starts on the next snap. The book does not assume good faith late in games, and on the evidence of how teams have tried to exploit it, that is the right assumption.
The 10-second runoff and the timeout that cancels it
After the two-minute warning of either half, Rule 4, Section 7 lists six acts a team may not use to save time:
- a foul by either team that stops the clock during a dead-ball period;
- intentional grounding;
- an illegal forward pass;
- throwing a backward pass out of bounds;
- spiking or throwing the ball in the field of play after a down has ended, except after a touchdown;
- illegally batting or kicking the ball out of bounds.
Each carries five yards unless a bigger penalty applies. For the offense, with time in, there is a second cost. The officials "will run off 10 seconds from the game clock and reset the play clock to 30 seconds," and the game clock then starts on the ready-for-play signal.
- 10Seconds taken off the game clock
- 30Play clock afterward, in seconds
- 5Minimum yardage for the act
- 1Timeouts needed to avoid it
From Rule 4, Section 7 of the NFL rulebook. The runoff applies only after the two-minute warning of either half and only against the offense; the yardage is five unless the act carries a larger penalty.
Three ways out of a runoff
The offense can use a timeout instead, in which case no time comes off and the clock starts on the snap. The defense can decline the runoff and keep the yardage. If the defense declines the yardage, though, the runoff goes with it, the play clock is set to 25 and the game clock starts on the snap, which almost no defense wants.
Section 7 also brings two neighbors into the same scheme. An illegal substitution with the ball dead and time in after the warning costs five yards and a runoff. And Article 4 adds a runoff when a replay review reverses a call, or a flag is picked up, and the correct ruling would have left the clock running. Neither team may decline that one, but either may spend a timeout to stop it.
If fewer than 10 seconds remain, the runoff ends the half. That is the purpose.
Why the defense is never charged one
Note 9 under Rule 4, Section 5, Article 4 is a single line: "There can never be a 10-second runoff against the defensive team." A runoff hurts the team that is trying to save time. A defense that fouls late is usually trying to stop the clock so it can get the ball back, so the book answers that differently. Under Item 2 the play clock is set to 40 and the game clock starts on the ready signal, unless the offense chooses the snap. And in the last 40 seconds of either half, Article 3 says that a defensive foul that conserves time, or an excess timeout for an injured defender, ends the half outright unless the defense has a timeout left or the offense chooses to play on. The trailing team cannot profit from its own infraction, and neither can a defense that would rather fake a cramp than call a timeout it no longer has.
Forward progress, sacks and a runner driven back out of bounds
Three plays catch viewers out more than any others, and all three follow from the same principle. The clock stops for what happened to the ball, not for where the players end up.
Forward progress stopped in bounds
A receiver catches the ball at the 40, is met by a linebacker, and is driven backward five yards and over the sideline. On the broadcast it looks like an out-of-bounds play. Under Rule 3, forward progress is "the point at which his advance toward his opponent's goal ends," and the ball is declared dead there "irrespective of the runner or receiver being pushed or carried backward." The play ended in the field of play. The ball never went out of bounds in the rulebook's sense, so item (c) of the stopping list never applies and the clock keeps running.
Late in a half that is brutal. A team with no timeouts sees its receiver carried out of bounds and the clock still moving. Officials signal it by winding the clock with a circling arm, which tells the operator the play ended inbounds. The rulebook text carries no separate late-game exception for a runner carried backward over the line, so the same reading applies with 30 seconds left as with 30 minutes.
What a receiver can control is how he goes down. One who turns and steps out before contact has gone out of bounds. One who is stopped first and then carried has not. When a runner is ruled down in the first place is covered in our guide to the NFL down by contact rule.
The sack
A sack is a tackle of a runner behind the line of scrimmage, and a tackle in the field of play does not stop the NFL clock. It keeps running unless something else intervenes: a fumble out of bounds, a foul, a timeout, the warning. This is why a sack in the final minute against a team that is out of timeouts is so often fatal. Offenses lose the yardage and then watch 20 or 30 seconds drain away while they get back to the line. A quarterback who takes that sack instead of throwing the ball away has lost twice. The throwaway, if legal, stops the clock as an incompletion.
The legality of that throwaway is the subject of our guide to the NFL intentional grounding rule. Grounding after the warning brings a 10-second runoff as well as its loss of down.
Kicks, scores and the untimed try
The clock on a kickoff does not start when the ball is kicked. Article 1 of Section 3 says it starts when the ball "is legally touched in the field of play." Until a player touches it there, the play may be running and the clock is not. The clock also stays stopped if the receiving team touches or recovers the ball in its end zone and does not bring it out, if the kicking team recovers the ball before anyone else legally touches it, or if the receiver makes a fair catch.
At the other end of the down the clock stops again, because item (a) of Section 4 stops it at the end of any free-kick down. The next snap is the first time the clock will start on its own. So a kickoff returned to the 30 costs exactly the time from first touch to tackle, and the returner's team then gets a fresh possession with the clock waiting for its first snap. The alignment and landing-zone rules that govern the kickoff itself have changed sharply in recent seasons, and the reasons are set out in our explainer on the NFL's kickoff rule changes.
Why every change of possession stops the clock
Item (i) stops the clock at the end of any down during or after which there is a change of possession, and the out-of-bounds and penalty exceptions both treat a change of possession as a reason for the clock to wait for the snap. The logic is that 22 players are leaving the field and 22 are coming on. A fresh offense should not have its first possession shortened by its own substitution. An interception returned to midfield and a turnover on downs are handled the same way.
Scores and the try
Every touchdown, field goal and safety stops the clock under item (d) or item (a). The try that follows is untimed. Rule 11 says it plainly: "The game clock will not run during the Try." A two-point attempt can involve a scramble that lasts eight seconds and none of it comes off the clock.
Field goals carry a small, precise provision that rarely gets noticed. For a successful field goal, or a miss that does not land in the field of play, the book caps the time that can run off the clock at five seconds. Snap, hold and kick rarely take longer than that anyway, so the cap mostly protects against a slow hand on the stop button: a successful kick snapped with eight seconds showing leaves at least three on the clock, and a team that needs those seconds for a kickoff and one last defensive stand will get them.
Untimed downs and why a half cannot end on a defensive foul
The rule is in Section 8 of Rule 4, and it is the reason a game can continue with zeroes on the scoreboard. If time expires during a down, the down is played to its end. If during that down the defense commits a live-ball foul and the penalty is accepted, the offense may extend the period by one untimed down after enforcement.
The reasoning is obvious once stated. Without it, a defense protecting a three-point lead on the final snap could simply tackle every receiver on the field. The penalty would be enforced, but with no time left there would be nothing to enforce it into.
The offense does not get the same treatment. Article 2(b) is blunt: "If there is a foul by the offense, there shall be no extension of the period." And if the foul occurs on the last play of the half, a score by the offense does not count. An offensive holding call on a Hail Mary that is caught in the end zone does not produce a replay. It ends the half.
The offensive fouls that do let the defense ask for more
The defense may still ask for an untimed down after an offensive foul in five situations, all of them cases in which the defense was harmed in a way the end of the period would leave unremedied.
- Illegal touching or first touching of a kick.
- Kick catch interference or fair catch interference.
- A palpably unfair act.
- A personal or unsportsmanlike conduct foul committed during a down before a safety, an interception, a fumble recovery or a turnover on downs.
- A foul by the kicking team before the receiving team secures possession on a scrimmage or free kick.
A double foul on the final down produces an untimed down too, with exceptions for dead-ball fouls and certain "clean hands" cases written into the enforcement rules. There can be more than one untimed down in a row; the article says so directly. A defense that commits a second foul on the untimed down gets a third, and so on.
When there is a try with no time left
If a touchdown is scored on the last play of a period, the try is still attempted, except in sudden-death overtime or where the touchdown ends the fourth period and a successful try "would not affect the outcome of the game." That second exception is why a team that scores to win by seven as time expires walks off without kicking.
Kneel-downs and the arithmetic of ending a game
A kneel-down is a dead ball the moment the quarterback goes to a knee, under Rule 7. The clock does not stop, because a runner down in the field of play is not on the stopping list. So the cost of each kneel in game time is the two or so seconds the snap and the knee take. The real consumption is the play clock that follows: up to 40 seconds of game time before the next snap.
Three kneels from a first down therefore control roughly two minutes, provided the defense cannot stop the clock between them. Every defensive timeout erases one of those 40-second gaps, because a charged timeout stops the game clock and, under the restart rule, the clock then waits for the next snap.
Read across the bars and the value of a timeout becomes concrete. With all three left, a defense facing a first down can keep the kneels from consuming more than a handful of seconds, and the offense will face fourth down with most of the time intact. With none, the same first down near the two-minute mark is the end of the game.
Starting from a running clock
If the game clock is already running before the first kneel, the offense adds one more play clock to the total. The catch is the two-minute warning. A series that straddles 2:00 is interrupted by a stoppage nobody had to spend a timeout on, and after it the clock waits for the snap, so one of the offense's 40-second gaps disappears exactly as if the defense had called time. An offense that gets its first down at 2:40 against a defense with no timeouts can still find itself facing fourth down with half a minute left, which is part of why the warning matters so much in this arithmetic. It gets its own treatment in our guide to the NFL two-minute warning.
Where it goes wrong
A kneel is not risk-free. The snap can be fumbled. A defense with nothing to lose will rush hard, and the book warns quarterbacks as much as defenders: if a quarterback does not go down immediately and contact from a rusher is unavoidable, it is not a foul unless it amounts to unnecessary roughness. The more common error is arithmetic: a team kneels on third down believing the clock will run out, discovers a few seconds remain, and has to punt or run a fourth-down play it did not plan.
The spike and the fake spike
A spike is an intentional grounding the rulebook forgives. Rule 8 lets a T-formation quarterback, defined in Rule 3 as a player lined up one yard or less behind the snapper, "stop the game clock legally to conserve time if, immediately upon receiving the snap, he begins a continuous throwing motion and throws the ball directly into the ground." The pass is incomplete. The clock stops under item (f). The offense loses a down and keeps the yards.
The conditions are precise. The quarterback must be under center, or close enough to count. He must throw at once and without a hitch. The next item in the same rule bans the "delayed spike": a passer who waits for strategic reasons and then throws the ball down in front of him has committed intentional grounding, which after the two-minute warning also brings a 10-second runoff.
What a spike costs
In time, very little: a second or so between the snap and the ball hitting the turf. The real cost is the run-up. With the clock running after a completion in bounds, the offense must sprint to the line, set for a full second, and snap. Getting that done can use 10 to 15 seconds of game clock, and the spike then saves the rest of the play clock.
In downs, a great deal. A spike on second down turns third-and-10 into the next real play. Teams calculate whether a timeout, which costs no down, is worth more than a spike, which costs no timeout. With 40 seconds left and one timeout, many coaches spike on first down and save the timeout for the field-goal unit. With 20 seconds and a long way to go, the down usually matters more.
The fake
November 27, 1994, Giants Stadium. The Miami Dolphins trailed the New York Jets late in the fourth quarter and drove deep into Jets territory with the clock running. Dan Marino gestured to his teammates that he would spike the ball, took the snap, and instead threw a touchdown pass to Mark Ingram in the corner of the end zone while the Jets defense straightened up. Miami won 28-24. The play is still called the "clock play" or simply the fake spike, and it works only because the real spike is so routine that a defense relaxes when it sees one coming. It is legal for a simple reason: a quarterback who does not throw the ball into the ground has not spiked anything and has just run a play.
Who keeps the time: the clock operator, the side judge and replay
Article 4 of Section 1 settles the question that NFL games once argued about for decades. "The stadium electric clock shall be the official time." The game clock operator works it, starting and stopping the clock on the signal of any official. He is not one of the seven on-field officials. The side judge supervises the timing of the game and, if the stadium clock fails or is not being run correctly, "shall take over official timing on the field."
That division of labor is visible to anyone who knows where to look. During a late drive the side judge's hand signals are often aimed at the clock operator as much as at the players, and when the clock does something odd he is usually the official the referee turns to first. Halftime is timed separately: the back judge times the 13-minute intermission.
Fixing a clock error on the field
Officials can correct the game clock "only before the next legal snap or kick, including an untimed down or Try." The deadline is absolute. Once the ball is snapped, a second that should have been restored is gone, and a second that should have run stays on the clock.
What replay can do
Rule 15 makes the game clock reviewable "for purposes of restoring time to the clock but not for purposes of taking time off the clock." Replay can restore seconds when the operator started the clock when it should have stayed stopped. It can review whether time had expired before a snap or whether the two-minute warning had arrived first.
The most delicate provision covers a ruling that time expired at the end of a half. Replay can put time back only if the video shows the clock should have stopped with two or more seconds left. In the first half the time is restored only if the next play will be a snap from scrimmage. In the second half it is restored only for a team trailing by eight points or fewer, or for either team in a tie. A replay official will not create a play that cannot change the result.
Replay can take time off in one way, and only indirectly. When a reversal after the two-minute warning turns a stopped clock into a running one, the clock is reset to when the play should have ended and the 10-second runoff described above applies. The broader limits on what the replay center in New York may change are set out in our explainer on NFL challenge and replay rules.
NFL clock rules compared with college football
The two rulebooks use the same 60 minutes in four 15-minute quarters and very different clocks. The gaps are widest on first downs and on out-of-bounds plays, which between them account for a large share of the extra snaps in a college game.
| Situation | NFL | NCAA college football |
|---|---|---|
| First down in the field of play | Clock keeps running | Clock keeps running, except in the last two minutes of each half, when it stops briefly for the chains (rule changed for 2023) |
| Runner out of bounds | Restarts on the ready signal, except late in each half and after a change of possession | Restarts on the ready signal, except after the two-minute timeout of the second or fourth quarter, when it waits for the snap |
| Late-half stoppage | Two-minute warning in the second and fourth quarters | Two-minute timeout in each half, added for 2024 |
| Time-saving foul late in a half | 10-second runoff against the offense after the two-minute warning | Has its own 10-second subtraction rule, with different triggers |
| Try after a touchdown | Untimed | Untimed |
Where the gap used to be widest
First downs, and it was not close. Until 2023 the college clock stopped on every one of them and waited for the chain crew, so a drive with six first downs collected six stoppages an NFL offense would never have been given. The NCAA removed most of that to cut the number of plays in a game, and kept the stoppage only inside the last two minutes of a half.
Out-of-bounds plays are closer than viewers assume. College starts the clock on the referee's signal there as well, and switches to the snap only after its own two-minute timeout, which is the same mechanism the NFL uses inside the last five minutes of the second half. The difference is the size of the late window, not the principle. The reasons a college game takes the time it does are taken apart in our guide to how long a college football game lasts.
Where they agree
On the essentials, mostly. Both stop the clock for an incompletion and a change of possession. Both play the try untimed. Both refuse to let a half end on an accepted defensive foul. And both put their own versions of the 40-and-25 play clock beside the game clock, which is the other half of the timing story and the subject of our guide to NFL play clock rules. The full list of the site's guides to the professional and college game is on our American football page.