Stopping Distance Calculator
A free, browser-based calculator. Runs entirely in your browser — no sign up, nothing stored.
100% FreeRuns in your browserBasic
Enter Values
Enter your values and press Calculate to see results.
How to use this calculator
- Enter the speed.
- Adjust reaction time and braking deceleration if needed.
How it works
Reaction distance = speed × reaction time; braking distance = speed² ÷ (2 × deceleration).
Worked example
60 km/h. ≈ 25 m reaction + 20 m braking = ~45 m.
Common mistakes
- Underestimating reaction time — 1.5 s is typical, fatigue makes it worse.
- Assuming dry grip — wet or gravel roads need much more distance.
Frequently asked questions
Why does speed matter so much?
Braking distance grows with the square of speed — doubling speed roughly quadruples the braking distance.
Related tools
Tip: Enter any known values to calculate the remaining results.
All calculations run in your browser. Your inputs are never saved or transmitted.