How to estimate cattle weight with a tape
Schaeffer formula (heart girth + body length)
Weight (lb) = heart girth² × body length ÷ 300, with both measurements in inches. In metric:
weight (kg) = heart girth² × body length ÷ 10,838, in centimeters. It is the most widely used field
formula because it accounts for the size of the animal in two dimensions.
Heart girth only
If you cannot measure body length, the calculator uses the Crevat formula, weight (kg) = 80 × heart girth³
with heart girth in meters. It is quicker but less accurate. Commercial weigh tapes use a similar heart-girth-only
table.
Example
A steer with 67 inches of heart girth and 59 inches of body length: 67 × 67 × 59 ÷ 300 ≈ 883 lb (about 400 kg).
Tips for accurate measurements
- Measure in the morning before the animal eats or drinks heavily.
- The animal should stand on level ground with all four feet square and its head in a natural position.
- Take two or three measurements and use the average.
- If you have access to a scale, weigh a few animals and compare, so you know how to adjust for your herd.
Frequently asked questions
How accurate is a cattle weight tape?
For adult cattle in normal body condition the error is usually around 5–10 % compared with a scale. It is less accurate for very young calves, very fat or thin animals, pregnant cows and animals with a full gut.
Where do I measure heart girth?
Right behind the front legs and shoulder blades, around the chest and perpendicular to the backbone. The tape should be snug but not tight, with the animal standing square and calm.
How do I measure body length?
From the point of the shoulder to the pin bone (point of the buttock), in a straight line. Adding body length makes the Schaeffer formula more accurate than heart girth alone.
What is the Schaeffer formula in pounds and inches?
Weight (lb) = heart girth² × body length ÷ 300, with both measurements in inches. For example, 67 in of heart girth and 59 in of body length give about 883 lb.