Calculate cornering speed from lateral G-force and turn radius, or acceleration speed from G-force and time in mph, km/h, and m/s.

Use lateral acceleration, not total felt g. Model assumes a circular path.

Classical model only; results do not establish safe driving or rotor speeds.

Illustrative radius presets

G-Force to MPH Formula

The following formula is used to convert G-Force to MPH.

MPH = sqrt(G × 32.17404856 × R) × (15 / 22)

Variables:

  • G is the lateral acceleration expressed in g
  • R is the radius of the turn in feet
  • MPH is the speed in miles per hour

For cornering, multiply the lateral G-force by standard gravity (approximately 32.17404856 ft/s²) and the turn radius in feet, take the square root, then multiply by 15/22 to convert ft/s to mph. G-force alone does not determine speed.

G-Force to Speed (mph) Conversion Table (Radius r = 100 m, g = 9.80665 m/s²)
G-Force (g) Speed (mph)
0.122.152
0.231.328
0.2535.025
0.338.368
0.444.304
0.549.533
0.654.261
0.7560.666
0.862.655
0.966.456
170.051
1.276.737
1.585.795
299.067
2.5110.760
3121.332
3.5131.053
4140.102
5156.639
6171.589
* Rounded to 3 decimals. Using v = √(G × g × r), with g = 9.80665 m/s² and r = 100 m. Conversion: 1 mph = 0.44704 m/s exactly.

What is G-Force?

G-Force, or gravitational force, is a measurement of the type of force per unit mass – typically acceleration – that causes a perception of weight, with 1 g being the force per unit mass due to gravity at the Earth’s surface (9.8 m/s^2 or 32.174 ft/s^2). In the context of circular motion, such as a vehicle taking a turn, G-Force can be felt as the centripetal force required to keep the vehicle in a curved path.

How to Calculate Speed from G-Force?

The following steps outline how to calculate the speed in MPH from G-Force.

  1. First, determine the G-Force experienced (G).
  2. Next, determine the radius of the turn (R) in feet.
  3. Use the formula above: MPH = sqrt(G × 32.17404856 × R) × (15/22).
  4. Finally, calculate the speed in MPH.
  5. After inserting the variables and calculating the result, check your answer with the calculator above.

Example Problem : 

Use the following variables as an example problem to test your knowledge.

G-Force experienced (G) = 2 g

Radius of the turn (R) = 100 feet