Stopping Distance Calculator
How far does a vehicle travel before it stops?
Your numbers
Your results
Reaction distance (m)
Reaction distance (m)
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Braking distance (m)
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Total stopping distance (m)
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Total stopping distance (ft)
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Stopping Distance Calculator by TheCalcTools
How the Stopping Distance Calculator works
Enter speed, your reaction time and the road surface.
Reaction distance is speed times reaction time.
Braking distance is v² ÷ (2μg) from the work-energy theorem.
The formula
d_reaction = v × td_braking = v² ÷ (2 μ g)
Worked example
Using the default values shown in the calculator:
| Speed (mph) | 60 |
|---|---|
| Reaction time (s) | 1.5 |
| Road surface | Dry road, average tires (μ ≈ 0.7) |
- 60 mph = 26.8 m/s. Reaction distance = 26.8 × 1.5 = 40.2 m.
- Braking = 52.4 m; total = 92.6 m (304 ft).
Result:
| Reaction distance (m) | 40.2 |
|---|---|
| Braking distance (m) | 52.4 |
| Total stopping distance (m) | 92.6 |
| Total stopping distance (ft) | 304 |
Frequently asked questions
Why does doubling speed quadruple braking distance?
Kinetic energy grows with the square of speed, and friction must remove all of it over the braking distance.
Is the friction coefficient reliable?
It varies with tires, surface and brake condition. The values are typical, not guarantees. Leave extra space in bad weather.
Sources and further reading
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This calculator gives estimates for information only. Check important results independently before you rely on them. See our disclaimer.