Horse Weight Calculator (Girth and Length)
Estimated weight of an adult horse from heart girth and body length, by the formula used by agricultural extension services, plus a daily forage figure.
Results
What this tool does
Few owners have a weighbridge, yet the weight matters for worming doses, feed and trailer loads. The classic formula, girth squared times length divided by 330 with inches and pounds, is generally considered better than a weight tape on its own because it also takes the length into account; here it is converted exactly to centimetres and kilograms. Measure the girth just behind the elbows and over the withers after the horse breathes out, and the length from the point of the shoulder to the point of the buttock. It is meant for adult horses: foals, small ponies, heavy draught breeds and pregnant mares need other equations, and the 2 % forage line is only the usual starting point, to be adjusted to work and condition.
Formula
weight (lb) = heart girth² (in) × body length (in) ÷ 330
Variables
| Symbol | Meaning | Unit |
|---|---|---|
gi | Heart girth (round the barrel, behind the elbows) | cm |
le | Body length (point of shoulder to point of buttock) | cm |
fp | Daily forage as share of body weight | % |
W | Estimated weight | kg |
WL | Same, in pounds | lb |
FD | Forage per day at that share | kg |
Worked example
- Heart girth (round the barrel, behind the elbows)190 cm
- Body length (point of shoulder to point of buttock)165 cm
- Daily forage as share of body weight2 %
- Estimated weight500 kg
- Same, in pounds1101 lb
- Forage per day at that share10.0 kg
Limitations
- The result is an estimate based only on the values you type. Real situations often include factors this calculator does not know about.
- The default values are typical reference figures, not measurements of your situation. Replace them with your own data whenever you have it.