Horse Weight Calculator — Heart Girth Method (Adult, Foal, Pony, Draft)
What does your horse weigh, in pounds or kilograms? This calculator estimates body weight using the standard heart-girth × body-length formula validated by Texas A&M Animal Science and Rutgers Cooperative Extension, with separate divisors for adults, yearlings, weanlings, foals, ponies and draft breeds. Accurate weight is essential for dosing dewormers and bute correctly — a 10% error in weight estimate equals a 10% error in drug dose.
Calculator
Measure just behind the withers, all the way around the horse.
From point of shoulder to point of buttock (pin bone).
Daily hay requirement
23.1 lb of hay per day (2 % of bodyweight).
Adjust for workload: add 0.25–0.5 % bodyweight of grain for light-medium work.
Average weights by breed
| Breed | Typical weight (lb) |
|---|---|
| Miniature horse | 150–300 |
| Pony (Shetland, Welsh) | 400–800 |
| Arabian | 800–1,000 |
| Morgan | 900–1,100 |
| Thoroughbred | 900–1,100 |
| Quarter Horse | 950–1,200 |
| Warmblood | 1,200–1,400 |
| Clydesdale / Percheron | 1,800–2,200 |
| Shire | 2,000–2,600 |
Horse weighing terminology
- Heart girth
- Circumference around the chest just behind the elbows and over the withers; main predictor in the weight tape formula.
- Body length
- Measured from point of shoulder to point of buttock (pin bone); second key input.
- Body Condition Score (BCS)
- 1-9 Henneke scale used by equine vets to grade fat cover at six locations; 5 is ideal.
- Weight tape
- Cloth tape calibrated to convert heart-girth measurement directly to estimated weight; accurate ±5-10%.
Frequently Asked Questions
How do you calculate a horse's weight without a scale?
Use the heart-girth × body-length formula: weight (lb) = (heart girth in inches)² × body length in inches ÷ 330 for adult horses. A horse with 76-inch girth and 66-inch body length weighs approximately 1,155 lb.
How accurate is a weight tape?
A weight tape marked in pounds is accurate to ±50–100 lb for adult horses. The heart-girth × body-length formula is slightly more accurate (±5–10 %) if measurements are careful.
Where do I measure heart girth?
Just behind the withers and around the barrel (not the chest), measured with the horse standing square. The tape should be snug but not tight.
What does an average horse weigh?
Thoroughbred 1,000 lb · Quarter Horse 1,100 lb · Warmblood 1,300 lb · Arabian 900 lb · Draft horse (Clydesdale, Percheron) 1,800–2,200 lb · Pony 400–800 lb · Miniature horse 150–300 lb.
How much hay should I feed per day?
Standard: 1.5–2.5 % of bodyweight per day. A 1,000 lb horse needs 15–25 lb of forage daily. Light work = 2 %, medium/heavy work = 2.5 % plus grain concentrate.
How do I weigh a foal?
For foals under 6 weeks, use the heart-girth-only formula: HG² × 0.07 − 300. Otherwise, stand on a scale with and without the foal (for small foals).
Sources & References
- [1]Texas A&M AgriLife Extension — Horse Body Weight Estimation — Texas A&M AgriLife
- [2]Rutgers Equine Science Center — Weight Tape Accuracy — Rutgers Equine Science Center
- [3]Merck Veterinary Manual — Equine Nutritional Requirements — Merck Veterinary Manual
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