40-Second Play Clock

Confused by the 40-second play clock?

How the play clock works:

The offense has 40 seconds to snap the ball after the previous play ends. The ball is ready for play when an official spots the ball and steps away to his position. The referee does not give a ready for play signal and does not wait for the chains to get set after a first down to start the game clock. The 40-second clock should still start at the end of the previous play if there was a first down.

A 25-second clock is used after an administrative stoppage. These are administrative stoppages:

  • Penalties
  • Timeouts
  • Injury/Helmet off
  • Measurement
  • Change of Possession
  • Touchdown
  • Try/FG/Safety/Kickoff
  • Start of overtime

If the 40-second count is interrupted because there is an appreciable delay in spotting the ball or for reasons beyond the control of the officials, the referee shall stop the game clock and signal to the back judge (both palms open in an over-the-head pumping motion) that the play clock should be re-set at 25 seconds and started when the ready-for-play signal is given.

Event * Play Clock Starts at Game Clock Starts on Covering Official’s Signal   Referee’s Signal
Dead ball inbounds 40 Running S7 None
Dead ball out of bounds 40 Snap S3 None
Incomplete pass 40 Snap S10 None
Team A awarded 1st down 40 Signal S3 S2
Penalty administration 25 Ready S3 S2
Charged team timeout 25 Snap S3 S1
Injury/Helmet off 25 Ready S3 S2
Measurement 25 Ready S3 S2
Double Change of possession-  Team A snaps 40 Ready S7 S2
Change of possession- Team B snaps 25 Snap S3 S1
Touchdown 25 N/A S5 S1
Try, FG, Safety 25 Varies Varies S1
Start of each period 25 Snap N/A S1
Legal kick 25 Snap S3 S1
Start of an overtime period 25 N/A N/A S1
Other administrative stoppage 25 Ready S3 S2

Position Mechanics 


The play clock starts as soon as the play ends and the ball is dead. On in-bounds plays, the covering official will raise his arm straight up for two seconds to indicate the 40-second play clock should start. On out-of-bounds plays, wave the clock dead just as you always have. You’re still signaling to the clock operator as you always have.

Back Judge

This rule gives you something to do back there. Simply, start the 40-second play clock when the previous play ends. At 10 seconds left, raise your arm until five seconds and start chopping.


If the ball is not spotted with approximately 20 seconds remaining on the play clock, re-set the play clock to 25-seconds. The only thing you actually need to worry about is not blowing your “ready” whistle on every play. You’ll still blow for resuming plays after administrative stoppages, but that’s all. Also, don’t wait for the chains to get set to start the game clock. You’re still signaling to the clock operator as you always have.