The most accurate way to weigh your horse is to walk him onto a livestock scale, like those used in veterinary hospitals or stockyards. But there are other methods for tracking his weight:
• A weight tape, which looks like a tailor’s tape but is marked in pounds instead of inches, is simple to use: Wrap it around your horse’s barrel, right behind the elbows where the girth rests, then record the reading where the ends meet. Weight tapes are notoriously inaccurate at gauging a horse’s true weight; but, if you take measurements regularly, they can be useful for tracking changes over time.
To get consistent readings, always place the tape in the same location behind your horse’s elbows and over his withers, and pull it snugly. Record measurements at the same time each day, under the same conditions. Exercise and rest can affect the readings.
• Calculate your horse’s weight with a standard tailor’s tape, plus some basic math. First, determine your horse’s girth circumference by measuring the distance in inches from just behind his elbow, up over his withers, and back to your starting point. Now measure the length of your horse’s body from the point of his shoulder to the point of his buttocks. Then, plug these two numbers into this equation: