Find the longitudinal position and height of your vehicle's center of gravity
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When you’re tuning a vehicle for performance, analyzing rollover risk, or designing a custom suspension setup, understanding where the center of mass sits is essential. The center of gravity influences everything from how the car handles through corners to how stable it is in emergency maneuvers yet most drivers never think about this invisible balance point that shapes the car’s behavior.
This car center of mass calculator helps you determine both the longitudinal position and height of your vehicle’s center of gravity. Using front and rear axle weights, wheelbase, and either a tilt test angle or direct height input, the tool computes the COG position, weight distribution percentages, and static stability factor. Whether you’re a motorsport engineer optimizing a race car, a safety analyst evaluating vehicle stability, or an automotive student studying vehicle dynamics, this calculator provides instant, accurate results. All processing runs locally in your browser, keeping your inputs private.
Enter the front axle weight using the first input field, selecting kilograms or pounds.
Enter the rear axle weight, the calculator will auto-sum these to give the total vehicle weight.
Specify the wheelbase, the distance between the front and rear axles — in meters, inches, or feet.
Choose the COG height method, Tilt Test (requires track width and tilt angle) or Direct Input (enter a known height).
For the tilt test method: enter the track width and the tilt angle at which the vehicle starts to tip.
For direct input: enter the known height of the center of gravity above the ground.
Review the COG position, weight distribution, height, and static stability factor in the results section.
The calculator uses the principles of static equilibrium to determine the longitudinal position of the center of gravity and the tilt test method to estimate the COG height. The calculations follow standard vehicle dynamics equations.
Formula: COG Position from Front Axle (a)
Formula: a = (W_rear / W_total) × L
Where W_rear is the rear axle weight, W_total is the total vehicle weight, and L is the wheelbase. This comes from taking moments about the front axle: the moment due to the total weight at distance a equals the moment due to the rear weight at distance L.
Formula: COG Position from Rear Axle (b)
Formula: b = (W_front / W_total) × L
Similarly, the distance from the rear axle is determined by the front weight fraction.
Formula: Weight Distribution Percentages
Formula: Front % = (W_front / W_total) × 100
Formula: Rear % = (W_rear / W_total) × 100
Formula: COG Height from Tilt Test
Formula: h = (Track Width / 2) × tan(θ)
Where θ is the tilt angle at which the vehicle begins to lift off the platform. This relationship comes from the geometry of a tilted vehicle at the point of tip-over, where the center of gravity is vertically above the pivot point.
Formula: Static Stability Factor (SSF)
Formula: SSF = Track Width / (2 × h)
The SSF is a dimensionless measure of a vehicle’s rollover resistance — higher values indicate better stability.
Consider a sports car with a front axle weight of 800 kg, rear axle weight of 600 kg, and a wheelbase of 2.8 meters. The track width is 1.6 meters, and the tilt angle is measured at 35°.
Step 1: Calculate total weight
W_total = 800 + 600 = 1,400 kg
Step 2: Calculate COG position from front axle
a = (600 / 1400) × 2.8 = 0.4286 × 2.8 = 1.20 m
Step 3: Calculate COG position from rear axle
b = (800 / 1400) × 2.8 = 0.5714 × 2.8 = 1.60 m
Step 4: Calculate weight distribution
Front % = (800 / 1400) × 100 = 57.1%
Rear % = (600 / 1400) × 100 = 42.9%
Step 5: Calculate COG height from tilt test
h = (1.6 / 2) × tan(35°) = 0.8 × 0.7002 = 0.560 m
Step 6: Calculate Static Stability Factor
SSF = 1.6 / (2 × 0.560) = 1.6 / 1.12 = 1.43
Interpretation: The sports car has a COG positioned 1.20 m behind the front axle (57.1% front weight distribution) with a height of 0.56 m above the ground. The SSF of 1.43 indicates good stability typical for a sports car or sedan.
The center of mass (or center of gravity) is the single point where the entire mass of the vehicle can be considered to act. It’s the balance point of the vehicle, the average position of all the mass distributed across the length, width, and height of the car.
A higher COG increases the risk of rollover because it reduces the static stability factor. SUVs and trucks have higher COGs and are more prone to rollover than sedans and sports cars with lower COGs. Lowering the COG improves stability and reduces rollover risk.
Use a set of vehicle scales placed under each axle. The vehicle should be on level ground with the driver and any typical load in place. The sum of the front and rear weights equals the total vehicle weight.
The Static Stability Factor is a measure of a vehicle’s rollover resistance, calculated as track width divided by twice the COG height. Higher SSF values indicate better stability values above 1.2 are generally considered good for SUVs and trucks, while sports cars often have SSF values above 1.5.
In a tilt test, the vehicle is placed on a tilting platform and slowly inclined until one side just begins to lift off. At this moment, the COG is vertically above the pivot point. The tilt angle and track width are used to calculate the COG height using h = (track width / 2) × tan(θ).
The ideal weight distribution depends on the vehicle’s purpose. A 50/50 front/rear distribution provides balanced handling for sports cars. Front-engine vehicles typically have 55–60% front weight, while mid-engine cars can achieve near 50/50. Rear-engine vehicles often have 40–45% front weight.
Lowering a car reduces the COG height, which improves stability, reduces body roll, and can enhance handling. The calculator shows exactly how much the SSF improves when you lower the COG.
Yes, the calculator works for any vehicle, modified or stock. Enter the actual weights and dimensions of your modified vehicle to get an accurate COG estimate. This is especially useful for race cars, off-road vehicles, and custom builds.
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