Before judging a pit call, count the stops that differ between the alternatives. Two rivals who both intend to stop are not asking the same question as a driver considering an additional stop. Confusing those comparisons makes an ordinary undercut look as though it must recover an entire trip through the pit lane in one lap.
The numbers below are invented teaching inputs, not estimates for a particular circuit, car or tyre. They illustrate the accounting; they are not a race-winning strategy model or a guide to an event's mandatory-stop rules.
First ask whether both cars will stop
An undercut is an attempt to stop before a rival and use a fresh-tyre pace advantage to get ahead after the rival's stop. The F1 glossary describes that sequence, including the possibility of the leader stopping to cover it.
If both cars make one stop, both incur a pit loss. In this model, that means time lost by taking the pit-lane route relative to staying on track, not merely the time stationary beside the mechanics. The difference between the two pit losses matters; their common cost cancels.
Consider two cars on the same lap. B is initially 2.0 seconds behind A and stops first. Across their staggered-stop sequence, suppose B gains 1.4 seconds in on-track running, including any warm-up effect, and all other running is equivalent.
The simplified comparison is:
B's new gap = initial gap − B's on-track gain + (B's pit loss − A's pit loss).
A positive gap means B remains behind; a negative gap puts B ahead in the model.
| Hypothetical case | Calculation | Modelled gap after both stops |
|---|---|---|
| Equal overall pit losses | 2.0 − 1.4 + 0 | B remains 0.6 seconds behind |
| B loses 0.8 seconds less through the pits | 2.0 − 1.4 − 0.8 | B is 0.2 seconds ahead |
Even if each car's assumed pit loss were 20 seconds, the equal-loss term would be 20 − 20 = 0. B does not need a 20-second on-track gain to overturn a two-second starting gap. But gaining some time is not sufficient either: the first row improves B's situation without reversing the order.
An additional stop really does add a cost
Now compare two plans for the same car, one with an extra stop. Assume that stop adds 20 seconds of pit loss, while replacement tyres save exactly one second per lap over the remaining 25 laps.
The hypothetical gross saving is 25 × 1 = 25 seconds. Deduct the extra 20-second cost and the model gives a five-second net saving. Break-even comes at 20 laps; fewer laps would not recover the cost under these assumptions.
This comparison starts from alternative plans, not a claim that a particular rival will be passed. A theoretical five-second improvement does not establish five seconds of usable passing opportunity. The car may rejoin in traffic, spend time warming its tyres or reach an opponent at a place where it cannot overtake.
For real analysis, the one-second gain cannot simply be assumed constant. It must be replaced with evidence or a stated range, and the comparison needs the relevant race conditions and feasible tyre/stop plans.
Why the overcut is not just waiting for a Safety Car
Stopping later can work when the earlier stopper's new tyres take time to become effective while the older tyres remain competitive. That is a different mechanism from waiting for a neutralisation, and from deliberately accepting a positional loss now to gain a tyre advantage later.
Jolyon Palmer's analysis of Singapore 2019 distinguishes those approaches and describes Vettel stopping on lap 19, with Leclerc following a lap later. By contrast, Mark Hughes's Monaco 2021 analysis explains why limited degradation and new-tyre warm-up made the balance between stopping early and staying out unusually delicate.
Those are dated examples, not universal circuit rules. Their value here is to show why the on-track-gain term needs evidence: “new tyres” alone does not specify its size or even guarantee the useful advantage a team needs.
Read the whole comparison window
Watch the gap before the first stop, the rejoining traffic, the staggered laps and the gap after both cars have stopped. A temporary place lost while only one rival has visited the pits does not settle whether the strategy worked.
Separate a slower pit service from a slow lap after leaving the pits. Both can change the outcome, but they are different inputs. A neutralisation can alter pit loss relative to the field and the gaps themselves; do not transplant an unchanged green-flag calculation into that situation or call the stop free.
The two examples omit changing conditions, overtaking, traffic and execution uncertainty except where explicitly included. Event rules can also rule out an otherwise attractive plan. This is a method for asking better questions of the timing screen, not a replacement for the information on a team's pit wall.
Correction note
Rewritten in September 2026 to remove an unsupported race anecdote and pit-loss figures, and to separate the same-stop and additional-stop comparisons. None of the worked numerical examples is attributed to an actual race.