Livestock owners often need to know the weight of their animals in order to determine proper feed rations, to administer the proper dosage of a medication, or to track how individual animals grow. A common tape measure can be used to measure the animal's girth circumference and body length. Using those measurements, the weight is calculated using the formula: Weight = (Girth X Girth X Length)/330 for Imperial units or Weight = (Girth X Girth X Length)/11916.3 for Metric units. Results can be saved for multiple animals and multiple measurements for the same animal to track growth over time.