Online Tool Store
Cattle Weight Estimator
Estimate cattle live weight from heart girth and body length using the university-verified formula, with a shrink allowance for marketing weight.
This works right here on your device — nothing gets sent out.
Health and farm tools
Cattle Weight Estimator
Measurements
Estimated weight
On-farm live weight
±5% typical accuracy vs. a certified scale
After shrink allowance
How it works
- Measure heart girth (chest circumference just behind the front legs) and body length (shoulder point to pin bone) with a flexible tape.
- Choose imperial (inches, pounds) or metric (centimeters, kilograms) — both use the same underlying relationship.
- The estimator calculates on-farm live weight, then optionally applies a shrink percentage to estimate post-transport marketing weight.
- Measure first thing in the morning before feeding for the most consistent result.
The formula
This is the standard heart-girth-and-length formula used by university extension programs (verified against Washington State University Extension and Mississippi State University Extension guidance, and cross-checked for unit consistency):
Weight (lb) = Heart girth² x Body length / 300 (inches)
Weight (kg) = Heart girth² x Body length / 10,840 (centimeters)
FAQ
How accurate is this estimate?
University extension trials report roughly ±5% accuracy compared to a certified scale when heart girth and body length are measured correctly. It is a farm-planning estimate, not a substitute for a scale — do not use it for buying, selling, or medication dosing decisions.
How do I measure heart girth and body length?
Heart girth is the circumference of the animal's chest just behind the front legs, measured with a flexible tape pulled snug (not tight) while the animal stands square. Body length is measured from the point of the shoulder to the pin bone.
Why does the formula divide by 300 in one unit system and 10,840 in another?
They are the same relationship expressed in different units. Converting the imperial formula's constant through inches-to-centimeters and pounds-to-kilograms gives almost exactly 10,840 — both versions describe the same body-volume-to-weight relationship.
What is the shrink allowance for?
Cattle lose weight in transport from reduced feed and water intake and manure loss ("shrink"). Typical pencil shrink is 2-3% for feeder cattle and 3-4% for finished cattle over a normal haul — enter a percentage to estimate the lower weight you would expect at a sale barn after transport.
Does this account for breed or body condition?
No — the heart-girth-and-length formula does not adjust for breed, frame size, or body condition score. Very lean, very fat, or unusually framed animals will estimate less accurately than the ±5% typical range.
How we compare
| Feature | Online Tool Store | CattleWeight AI (Agarwal's Formula calculator) | Farmer Grows Livestock Calculator |
|---|---|---|---|
| Heart girth + body length formula | Yes | Yes | Yes |
| Imperial and metric units | Yes | Yes | Yes |
| Shrink allowance for post-transport weight | Yes | Not shown | Yes |
| No sign-up or waitlist | Yes | Calculator free, AI app is waitlist-only | Yes |
For a quick farm estimate without extra subjective inputs to fill in, this keeps the same university-verified formula the paid tools use and is upfront about the ±5% accuracy range and what the formula does not account for, like breed or body condition.