By determining the weight per linear foot of a material, you know how much any length of the substance weighs. The weight per foot is also known as linear weight density. This equals the weight in pounds of the object, such as a rope, divided by its total length in feet. For some applications, such as competitive sailing, it is important to know the weight per foot of rope to avoid adding too much weight to the sails.

Place the entire length of the object on a scale to determine its weight. For example, say you have 5 lbs. of rope.

Measure the length of the object in inches. Continuing the example, the length of the rope is 102 inches.

Convert the length to feet by dividing by 12. This would be 102 inches divided by 12 for a length of 8.5 feet.

Divide the weight by the length to obtain the linear weight density in pounds per foot. Completing the example, 5 lbs. divided by 8.5 feet equals 0.6 lb. per foot.