Horse Bodyweight Calculator
Estimate bodyweight from heart girth and body length measurements when a livestock scale is not available, then keep a private history in this browser if you choose.
Weight over time
What you work out here stays on this device. Log in to save it and keep a history against a named horse. Nothing is sent anywhere unless you press Save.
A useful estimate, not a scale.
With measurements converted to inches first, the adult equation is heart girth × heart girth × body length ÷ 330. Oregon State Extension publishes constants of 301 for a yearling and 280 for a weanling. The adult equation is also offered for an adult horse only.
This is an adult-horse equation, and it is least reliable exactly where a horse's build differs from the light-horse proportions it was derived from. Ponies, draft types, heavily pregnant mares and unusually short-coupled or long-backed horses all sit outside it. There was previously an “Adult pony” option here; it has been removed, because it applied the identical adult-horse divisor and so implied an adjustment the arithmetic never made. For those horses, treat the result as a trend line for the same horse measured the same way rather than an absolute weight, and use a livestock scale wherever one is available, particularly before calculating a medication dose.
The selected sources do not support one honest error percentage for every breed, condition and body type, so this tool does not manufacture one. Repeatable measurements are most useful for seeing a trend. A scale remains the accurate method.
This estimate is useful for tracking and general management. Use a livestock scale or weight confirmed by a veterinarian when precise dosing matters.
Related: Supplements and conditions.
Sources
- University of Minnesota College of Veterinary Medicine: body measurements
- University of Tennessee Extension: Estimating a Horse’s Weight
- Oregon State University Extension: equine weight calculator
Page content last reviewed by Lazy K on August 25, 2026 against the sources above. This is an editorial review, not a veterinary review: no veterinarian has reviewed or approved this page.