What is the Schaeffer formula?

The Schaeffer formula is HG² × BL ÷ 300 (imperial), where HG is heart girth in inches and BL is body length in inches. The result is the estimated weight in pounds. It is widely used because it accounts for both girth and length, giving a more accurate estimate than girth alone.

How accurate is heart-girth weight estimation?

Estimates typically fall within ±10–15% of actual scale weight for average-condition animals. Accuracy decreases for very fat or very thin cattle, pregnant cows near term, or breeds not matched to the formula coefficients.

Where do I measure heart girth?

Wrap the tape snugly around the animal's body immediately behind both front legs and the top of the withers. Keep the tape perpendicular to the spine and record the circumference.

Where do I measure body length?

Measure in a straight line from the point of the shoulder (top of the front leg joint) to the pin bone (point of the buttock). Do not follow the curve of the body.

Which method should I use — Schaeffer or heart-girth-only?

Use the Schaeffer formula when you have both measurements — it is more accurate. The heart-girth-only method is useful when measuring body length is impractical, such as with a restless animal.

Does this work for calves?

The formulas are calibrated for mature and growing beef and dairy cattle. For very young calves (under ~3 months), accuracy decreases. Use the result as a rough guide only.

Cattle Weight Estimator

Enter heart girth (and optionally body length) to estimate live cattle weight using the Schaeffer formula or breed-specific heart-girth tables.

Measurements

Unit System

Estimation Method

Heart Girth (inches)

Circumference just behind the front legs at the withers.

Body Length (inches)

Straight-line distance from point of shoulder to pin bone.

Estimated Weight

Enter measurements and click Estimate Weight.

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Summary

The Cattle Weight Estimator calculates live body weight from simple tape measurements taken in the field. It implements the Schaeffer formula (HG² × BL ÷ 300) for maximum accuracy when both heart girth and body length are available, and provides heart-girth-only estimates using published coefficients for beef and dairy breeds. Both imperial and metric unit systems are supported.

How it works

Select your preferred unit system: imperial (inches / pounds) or metric (cm / kg).
Choose the estimation method: Schaeffer formula uses heart girth + body length; heart-girth-only uses breed-specific coefficients.
Measure the heart girth — the circumference just behind the front legs — and enter it.
For the Schaeffer method, also measure body length from the point of shoulder to the pin bone and enter it.
Click Estimate Weight to see the calculated live weight.

Use cases

Estimate cattle weight without a livestock scale when purchasing or selling animals.
Calculate drug or anesthesia doses based on estimated body weight.
Monitor weight gain over time with periodic tape measurements.
Screen herd condition quickly during field veterinary visits.
Help small producers track growth rates in beef and dairy calves.

Frequently Asked Questions

Last updated: 2026-06-19 · Reviewed by Nham Vu