Free interactive tool
Stopping Distance Calculator
Thinking distance plus braking distance — and why speed matters more than it feels.
Count the meters before the car stops
Speed, reaction time, and the road surface each claim distance. The bars show who takes how much.
Reaction distance grows in a straight line with speed, but braking distance grows with its square — which is why small speed changes matter more than they feel.
- Double the speed from 30 to 60. Did the total stopping distance double?
- Switch the road to wet and find the speed that stops as short as 60 km/h on dry.
Stopping is two distances: the car you drive during your reaction time, and the braking distance — which grows with the square of speed. Double the speed and braking distance quadruples.
Switch the road to wet and watch the grip term stretch everything: the same 60 km/h needs far more room in the rain than intuition budgets.
How far to stop from 60 km/h?
Around 36–40 m on dry roads with a 1 s reaction — roughly 8–9 car lengths.
What changes most in the wet?
Grip: braking distance roughly doubles, while thinking distance stays the same.