How to use the car stopping distance calculator
Estimate reaction, braking and total stopping distance. Enter speed, reaction time, tyre friction coefficient in the fields above; the reaction distance, braking distance, total stopping distance are computed instantly and plotted on the chart so you can see how the answer changes.
Formula
Variables
- v — Speed (km/h)
- tr — Reaction time (s)
- mu — Tyre friction coefficient
Worked example
With speed = 100 km/h, reaction time = 1.5 s, tyre friction coefficient = 0.7, the calculator gives reaction distance ≈ 41.66667 m; braking distance ≈ 56.20129 m; total stopping distance ≈ 97.86796 m.
Frequently asked questions
What is the formula for the car stopping distance calculation?
Reaction distance (m) = v / 3.6 × tr. Braking distance (m) = (v / 3.6)^2 / (2 × mu × GRAV). Total stopping distance (m) = [Reaction distance]+[Braking distance]. Here v is speed (km/h), tr is reaction time (s), mu is tyre friction coefficient.
What inputs do I need for the car stopping distance calculator?
You need speed in km/h, reaction time in s, tyre friction coefficient. Each field is pre-filled with a typical example so you can see how the result responds as you edit the numbers.
How do I use this calculator?
Type values into the input fields. Results and the chart update instantly. Use Reset to restore the example values, Copy results to paste them elsewhere, or Share to copy a link that preserves your inputs.
Is the result exact?
Calculations use standard formulas and double-precision arithmetic, then display about seven significant figures. Real-world measurements carry uncertainty, so treat results as estimates unless your inputs are exact.