Braking Distance
Calculator
Results
- Braking distance (m)
- 49.176129
- Braking distance (ft)
- 161.339006
- Deceleration (m/s²)
- 7.84532
- Braking time (s)
- 3.540681
Results
| Braking distance (m) | 49.176129 |
| Braking distance (ft) | 161.339006 |
| Deceleration (m/s²) | 7.84532 |
| Braking time (s) | 3.540681 |
formula-map diagram
- Braking distance (m)
- 49.176129
- Braking distance (ft)
- 161.339006
- Deceleration (m/s²)
- 7.84532
- Braking time (s)
- 3.540681
Formula breakdown
Formula
d = v² ÷ (2 × μ × g)= 49.176129098087
Note
Simplified model: results use idealised textbook relationships and ignore real-world factors such as driving style, load, temperature, aerodynamic and rolling losses, drivetrain efficiency, tyre and brake condition and road surface. CO2 figures are tailpipe only, based on the standard 2.31 kg CO2 per litre of petrol (2.68 kg per litre of diesel), and exclude fuel production and distribution. Use them as estimates, not as legal, safety or load-rating figures.
More in Automotive and transport
See all →Frequently asked questions
What is braking distance and how is it different from stopping distance?+
Braking distance is specifically the distance a vehicle travels from the moment brakes are applied until it comes to a complete stop, excluding driver reaction time. Stopping distance is the broader figure that adds the distance covered during the driver's reaction time before braking even begins.
How is braking distance calculated?+
A standard physics-based formula is: braking distance = speed² ÷ (2 × deceleration), where deceleration depends on factors like tire grip, road surface, and braking system. Because speed is squared, braking distance grows much faster than speed itself — doubling speed roughly quadruples braking distance.
Why does doubling your speed more than double your braking distance?+
Kinetic energy scales with the square of velocity, and that energy must be dissipated as heat through the brakes and tires to stop the vehicle. Since braking distance is proportional to speed squared (for constant deceleration), going from 30 to 60 mph doesn't double the distance needed — it roughly quadruples it.
What's a common misconception about wet or icy road braking distance?+
People often underestimate how much friction (and therefore deceleration capability) drops on wet or icy surfaces — braking distance can easily double on wet pavement and increase by 5-10 times on ice compared to dry pavement, far more than intuition based on 'a little less grip' would suggest.
Does this calculator account for anti-lock brakes (ABS) or tire condition?+
The deceleration value used in the calculation should reflect these factors, but the calculator itself typically uses a single deceleration rate you specify or a standard assumed value — it doesn't automatically model ABS engagement or reduced grip from worn tires unless you adjust the deceleration input accordingly.