Car Center of Mass Calculator

The center of mass is a unique point at which a vehicle behaves as if all its mass were concentrated there. If a force is applied directly at this point, the car moves in that direction without rotating. For vehicles, three coordinates describe it: longitudinal (front-to-rear), lateral (side-to-side), and altitudinal (height from ground).

The CG height and position directly affect a vehicle's handling, stability, and safety. A lower CG reduces the risk of rollover and improves cornering ability. Race cars are engineered for the lowest possible CG, while trucks and SUVs have higher CGs that make them more prone to tipping. Understanding CG is also critical for suspension tuning and brake bias settings.

Drive each axle over a set of vehicle scales (like corner weight scales or a truck scale). Record the weight shown for the front axle and rear axle separately while the car is on a flat, level surface. Make sure the fuel load and driver weight match your intended measurement conditions.

Raising the rear changes how the weight distributes to the front axle. By comparing the front axle weight when level versus when the rear is raised by a known height, the calculator can determine how high the center of gravity sits above the ground. Without this second measurement, only the longitudinal (front-to-rear) position can be found.

The CG height formula is: CG Height = Tire Radius + (Wheelbase × (Front Weight Raised − Front Weight Level) / Total Weight) / sin(arctan(Raise Height / Wheelbase_horizontal)). In simplified form, the change in front axle load caused by tilting the car, combined with the geometry of the raise, reveals how high the mass center is located.

Weight bias is the percentage of the total vehicle weight resting on each axle. A 50/50 split means equal weight front and rear — considered ideal for balanced handling. Front-wheel-drive cars typically have 60–65% front bias due to the engine and transmission being over the front axle. Rear-wheel-drive sports cars often target a 50/50 or even slight rear bias.

For a solid, uniform object, the center of mass is always inside the body. However, for hollow or irregularly shaped objects — like a donut or a boomerang — the CG can technically fall in empty space. For a typical car, the CG is always located within the physical bounds of the vehicle, usually somewhere in the lower-middle portion of the cabin area.

In most engineering and everyday contexts, center of mass and center of gravity are used interchangeably. Technically, center of mass is the average position of all mass in the object, while center of gravity is the point where gravitational force effectively acts. They differ only in non-uniform gravitational fields — which is irrelevant for car calculations on Earth's surface.