Stopping Distance Calculator

Estimate total stopping distance for a vehicle from its speed, the driver's reaction time and the road's grip, splitting it into thinking distance (covered before you react) and braking distance (covered while slowing). Pick a road condition preset to set the tyre–road friction coefficient (dry, wet, snow, ice) and a reaction-time preset, then adjust. The braking distance uses the constant-deceleration model v² ÷ (2·g·μ). Useful for driver education and understanding how speed and conditions multiply stopping distance. Pure arithmetic — a real emergency stop also depends on brakes, tyres, gradient, ABS, surface type and whether you were paying attention. Everything runs locally in your browser.