How accurate is this formula?

The Carroll & Huntington formula is accurate to within about 5–10 % for most light horse breeds. Draft horses and ponies may vary more; for critical dosing always confirm with a veterinarian.

Where do I measure the heart girth?

Wrap a soft tape measure around the horse's barrel just behind the withers and elbows, making sure the tape is snug (not tight) and level on both sides.

Where do I measure body length?

Measure from the point of shoulder (the bony protrusion at the front of the shoulder) straight back to the point of buttock (the bony protrusion at the back of the hindquarter).

Can I use this for foals or ponies?

This formula is validated for adult light horses. For foals under 6 months, ponies, or draft breeds use a species-specific formula and consult your vet.

Horse Weight Calculator

Name: Horse Weight Calculator
Availability: InStock
Author: Nham Vu

Enter your horse's heart girth and body length (in inches or centimetres) to get an estimated body weight in pounds or kilograms.

Measurements

Unit System

Heart Girth (inches)

Measure around the barrel, just behind the withers and elbows.

Body Length (inches)

From point of shoulder to point of buttock.

Enter measurements and press Calculate

Summary

Enter your horse's heart girth and body length (in inches or centimetres) to get an estimated body weight in pounds or kilograms.

How it works

Measure the heart girth (the circumference of the horse's body just behind the front legs) and the body length (from the point of shoulder to the point of buttock). The tool applies the standard formula (HG² × BL ÷ 330 for inches/lbs, or HG² × BL ÷ 11,877 for cm/kg) and returns the estimated weight.

Use cases

Estimate medication or dewormer dosage based on body weight.
Monitor weight gain or loss over time without a livestock scale.
Plan feed rations that are proportional to body size.
Screen for obesity or underweight conditions before a vet visit.

Frequently Asked Questions

Last updated: 2026-06-11 · Reviewed by Nham Vu