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Rollout Calculator
Calculate tire rollout and revolutions per mile
Rollout is a tire's circumference — the distance the car travels per tire revolution, including growth at speed for slicks.
Formula: Rollout = π × diameter · Revolutions per mile = 63,360 ÷ rollout (inches)
What this number means
This calculates rollout — the distance a tire travels in one full revolution — from diameter or a measured circumference, plus revolutions per mile. Rollout is the number that ties tire size to gearing, speed and the stagger used on circle and drag applications.
What to change next
Measure rollout with a tape on the actual tire at race pressure when precision matters, because marked diameter and real rollout differ, especially between two 'matching' slicks. A rollout mismatch side to side can pull a car off line, so check pairs, not just one tire.
Worked example
A tire with a 90 in measured circumference has a rollout of 90 inches and turns ≈ 704 revolutions per mile.