Two seconds of perfection
A modern F1 pit stop changes all four wheels in around two seconds; the world record is 1.80 seconds. About twenty crew members touch the car: three per wheel (gun, off, on), front and rear jacks, side stabilizers, and a release controller watching for traffic.
There has been no refueling since 2010 — cars start heavy with up to 110 kg of fuel and run to the end. The stop is purely about tires (and occasionally a new front wing).
Where the time actually goes
The stationary time is the headline, but the true cost of a stop is the whole pit lane transit: entry, the speed-limited lane (80 km/h), the stop itself, and the exit. Total 'pit loss' runs 18–25 seconds depending on the circuit — that's the number strategists actually use.
A slow stop of four seconds barely matters; a cross-threaded wheel nut costing thirty seconds is a race-ruiner. Teams therefore optimize for consistency over outright record attempts.
Stops as strategic weapons
Because pit loss is fixed, the game is choosing when to pay it. Stopping earlier than a rival to attack on fresh tires is the undercut; staying out longer in clear air is the overcut. Safety cars slash the effective cost of a stop, which is why the pit wall erupts into calculation the instant one is called.
Double-stacking — pitting both cars in one go — saves a safety-car opportunity but risks disaster if the first stop stumbles.