How to Figure the Center of Gravity

Determine the weight of the object. An example that can help illustrate this process is an airplane.

Weigh any additional objects that would be added to the original object. If it is an object that will house additional weight, for example the pilot and copilot of an airplane, the additional objects must be weighed separately.

Add the weights of all objects to get a total weight amount.

Choose a starting point, called the "datum," at one end of the object. When measuring the object, determine the longest point of length that the object has. Continuing with the airplane example, this would be the point from the nose of the plane to the tail. The starting point for this measurement is referred to as the datum.

Measure the distance from the datum to the center of each object. In the example of the airplane, we would measure from the datum to the center of the plane, and then from the datum to the center of each person.

Multiply the weight of each object by the length of measurement from the datum to the center of the object. In the airplane example once again, the length of the datum to the center of the pilot would be multiplied by the pilot's weight. The length of the datum to the midpoint of the plane would be multiplied by the weight of the plane. Each of these numbers is referred to as the object's "moment."

Add all of the moments to get a total moment amount.

Divide the moment amount by the weight amount. The result will be a number, which is the amount of feet from the datum to the center of gravity on the object.