Pig Weight Calculator: Estimate Pig Weight from Body Measurements

Weighing pigs accurately requires a livestock scale, which many smallholders don't own. The Pig Weight Calculator provides a reliable estimate using a soft tape measure and the industry-standard girth-length formula. This is the same method used by veterinarians and farm advisers when accurate scales are unavailable.

The formula used is: weight (kg) = girth (m)² × length (m) × 69.3, where girth is measured around the chest just behind the front legs and length is measured from between the ears to the base of the tail along the topline.

The calculator returns an estimated weight in kilograms alongside a weight classification: piglet (under 25 kg), weaner (25–50 kg), grower (50–80 kg), finisher (80–110 kg), or heavy (over 110 kg). Measurements that fall outside expected ranges for the animal's size are flagged with a warning.

The girth-length formula for pigs is documented in veterinary dosing literature and is referenced in the AHDB Pork technical guides as an acceptable weight estimation method. The coefficient 69.3 is specific to pigs and reflects the typical body density and conformation of commercial pig breeds. Accuracy is typically within 5–10% of true weight for standard breeds in normal body condition.

Measure the girth in metres by wrapping a soft tape around the pig's chest just behind the front legs with the pig standing square. Measure body length from between the ears to the base of the tail. Enter both measurements. The estimated weight will appear immediately. When medicating based on estimated weight, round up to the nearest 5 kg and confirm the dose with your vet.