The formula
This tool uses Schaeffer’s formula, widely taught to farmers and vets because it needs only a tape:
Weight (kg) ≈ heart girth (cm)² × body length (cm) ÷ 10,840
(original: weight (lb) = girth (in)² × length (in) ÷ 300)
Example: girth 170 cm and length 140 cm → 170 × 170 × 140 ÷ 10,840 = 373 kg.
How to measure correctly
- Make the animal stand square on level ground with its head up.
- Heart girth: pass the tape around the chest just behind the front legs and shoulder blades. Pull snug, read after the animal breathes out.
- Body length: from the point of the shoulder in a straight line to the pin bone at the tail end.
- Measure twice and use the average.
How accurate is it?
For healthy adult cattle the estimate is usually within about 5–10% of scale weight. It is less accurate for very young, pregnant, very fat or very thin animals, and for goats and sheep with thick coats. For medicine doses, when in doubt ask your vet — under-dosing dewormers can cause resistance.
Questions people ask
Can I use only the girth?
Girth-only tapes exist and are printed for specific breeds. Adding body length makes the estimate more reliable across breeds.
Does it work for buffaloes?
Yes, as an estimate. Buffaloes are often heavier for the same measurements; compare with a scale weight when you can.
How much should a cow eat?
As a rough guide, dry matter intake is about 2.5–3% of body weight per day, more for high-yielding cows. Your vet or dairy cooperative can advise on a balanced ration.
Sources
Weight estimates guide feeding and dosing; follow your veterinarian’s advice for medicines. Last reviewed: November 2026.