Horse Weight Calculator (Girth and Length Tape Method)
Measure heart girth and body length with a soft tape to estimate your horse’s weight.
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Horse Weight Calculator (Girth and Length Tape Method) by TheCalcTools
How the Horse Weight Calculator (Girth and Length Tape Method) works
Carroll and Huntington (1988) found that weight (kg) = heart girth² (cm) × body length (cm) ÷ 11,880 predicts the weight of adult horses within a few percent. In inches the same formula is girth² × length ÷ 330 = weight in lb.
Horses generally need about 1.5% to 2.5% of body weight a day in forage (dry matter). Use the weight to dose dewormers and medicines only as your vet directs.
The formula
Worked example
Using the default values shown in the calculator:
| Heart girth (cm) | 190 |
|---|---|
| Body length (cm) | 165 |
| Daily forage | 2 % of body weight |
- 190² × 165 ÷ 11,880 = 501 kg (1,105 lb).
- At 2% of body weight, feed about 10.0 kg of forage a day.
Result:
| Estimated weight (kg) | 501 |
|---|---|
| Estimated weight (lb) | 1,105 |
| Forage per day (kg, dry matter) | 10.0 |
| Typical water intake (litres per day) | 25 to 50 L, more in heat or work |
Frequently asked questions
Does this work for ponies and foals?
It is designed for adult horses. Ponies, draft horses, foals and pregnant mares need breed-specific formulas or a scale.
How accurate is a weight tape?
Commercial weight tapes use girth only and can be off by 10% or more; adding body length improves the estimate.
Sources and further reading
- Carroll CL, Huntington PJ (1988). Body condition scoring and weight estimation of horses. Equine Veterinary Journal 20:41-45
- Wikipedia: Horse care
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This calculator gives estimates for information only. Check important results independently before you rely on them. See our disclaimer.