How to Measure a Vaulted Room in Cubic Feet

Measure the dimensions of the room in feet. You need to know the length, width, height to the point that the ceiling begins to vault and the height of the vaulted ceiling extending above where the vaulting starts.

Multiply the length times the width times the height of the room to the point the vaulting starts to vault. This is the volume of the room if the ceiling were not vaulted. For example, if the room measures 22-by-18 feet and the wall goes up 10 feet before starting to vault, multiply 22 by 18 by 10 to get 3,960 cubic feet.

Multiply the dimension that runs perpendicular to the vaulting by the vaulting height by 1/2. In this example, if the vaulted ceiling runs perpendicular to the length (22 feet) and the vaulting adds 4 feet to the height, multiply 4 by 22 by 1/2 to get 44 square feet.

Multiply the result by the dimension parallel to the vaulting to find the volume the vaulting adds to the room. In this example, multiply 44 square feet by the 18 foot width to get 792 cubic feet.

Add the volume of the room without the vaulting to the volume added by the volume to find the volume of the vaulted room. In this example, add 3,960 cubic feet to 792 cubic feet to find the total volume equals 4,752 cubic feet.