How to Estimate a Horse's Weight

There are many things that can cause a horse to drop weight, such as parasites, stress and sickness, but most often it is related to feeding. Since hay and grain are fed by weight, it's important to know your horse's weight. While many horsemen simply make an educated guess about their horse's weight, there is a more accurate way to calculate your horse's weight using a formula developed by equine nutritionists.

Things You'll Need

  • Measuring Tape
  • Calculator
  • Pen and Paper
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Instructions

    • 1

      Review the formula you will use to calculate your horse's weight. The formula is: body weight (in kilograms) = [girth circumference squared (in centimeters) x body length (in centimeters)] / 11,877.

    • 2

      Measure the circumference of your horse's girth. Starting behind your horse's wither lay a measuring tape around your horse's barrel, just behind the elbow and around the narrowest part of his trunk. Write down this number.

    • 3

      Measure the body length of your horse. Place one end of the measuring tape in the center of your horse's chest, pull it straight along her side and end in the center of the tailbone. Write down this measurement.

    • 4

      Convert both measurements (girth and length) from inches to centimeters by multiplying the number of inches by 2.54. For example, for a horse with a girth that is 75 inches, you would multiple 75 times 2.54, which equals 190.5 centimeters.

    • 5

      Square the measurements for the girth. Do this after you have already converted the measurement in to centimeters. If you are not a math wiz, this is easiest to do using a calculator.

    • 6

      Multiple the circumference of the girth squared (in centimeters) by the number of the body length (in centimeters).

    • 7

      Divide this number by 11,877. This will give you the weight of your horse in kilograms.

    • 8

      Multiple the final numbers by 2.2 to get your horse's weight in pounds; for instance, if your horse weighs 578 kilograms he would weight 1,721 pounds.