What this calculator does
Horse weight estimate works out estimated adult horse body weight from a heart-girth and body-length tape measurement. Enter your own figures above and the answer updates as you type: nothing is fixed in the code, so the result reflects exactly the numbers you supply.
The formula this calculator evaluates is printed under the tool and explained below, so you can check the working by hand or reuse it in a spreadsheet.
The formula
The inputs explained
| Field | What to enter |
|---|---|
| Heart girth (circumference behind the withers/elbow) (in) | A number, measured in in. Starts at 72. |
| Body length (point of shoulder to point of rump) (in) | A number, measured in in. Starts at 66. |
Worked examples
Every figure in the tables below is produced by this page’s own calculator at build time, so the numbers and the tool always agree. Select any row to load that scenario.
How the answer changes with heart girth (circumference behind the withers/elbow)
Every other input is held at the calculator’s starting values while heart girth (circumference behind the withers/elbow) varies. Select any row to load that scenario into the calculator.
| Heart girth (circumference behind the withers/elbow) (in) | Estimated body weight | In kilograms | Formula used |
|---|---|---|---|
| 36 | 259 lb | 118 kg | Weight (lb) = girth² × length ÷ 330, accurate to roughly ±10% for adult, mature-build horses |
| 54 | 583 lb | 265 kg | Weight (lb) = girth² × length ÷ 330, accurate to roughly ±10% for adult, mature-build horses |
| 72 | 1,037 lb | 470 kg | Weight (lb) = girth² × length ÷ 330, accurate to roughly ±10% for adult, mature-build horses |
| 108 | 2,333 lb | 1,058 kg | Weight (lb) = girth² × length ÷ 330, accurate to roughly ±10% for adult, mature-build horses |
| 144 | 4,147 lb | 1,881 kg | Weight (lb) = girth² × length ÷ 330, accurate to roughly ±10% for adult, mature-build horses |
| 216 | 9,331 lb | 4,233 kg | Weight (lb) = girth² × length ÷ 330, accurate to roughly ±10% for adult, mature-build horses |