Stopping Distance Calculator
Enter your speed, reaction time and the road's friction coefficient to estimate total stopping distance.
Stopping Distance Calculator
Estimate total stopping distance — reaction distance plus braking distance — for a given speed and road condition.
Total stopping distance has two parts: the reaction distance covered before you start braking, and the braking distance itself, which grows with the square of your speed. This calculator combines both using standard physics formulas.
Example
- With the default values shown above, this calculator returns: Reaction Distance (m) ≈ 41.67; Braking Distance (m) ≈ 56.18; Total Stopping Distance (m) ≈ 97.85.
Frequently Asked Questions
What friction coefficient should I use?
Roughly 0.7 for dry asphalt, 0.4 for wet roads, and as low as 0.1 for icy roads. Actual values vary with tires, tread wear and road surface.
Why does stopping distance increase so much with speed?
Braking distance is proportional to the square of your speed, so doubling your speed roughly quadruples your braking distance, even though reaction distance only doubles.