A decent pitstop is around 2.2 - 2.4 seconds. This is the time from when the car comes to a complete stop until it leaves the box. During this time all four tyres are changed and occasionally a wing is adjusted.
Red Bull currently holds the record at 1.82 seconds, however, subsequent to this remarkable feat, the FIA has introduced a 0.2-second delay, from when the last wheel is fixed until the car can leave. This is to provide reaction time if there is an issue and therefore reduce the chances of a failure and an accident.