If you own a horse, you already know how important it is to keep track of their weight. Whether you’re trying to figure out the exact dosage for a dewormer, checking if they’re dropping pounds over winter, or calculating their daily hay allowance, getting an accurate weight is rule number one of horse care.
But let’s be real: almost none of us have a giant, expensive livestock scale sitting around the barn!
The good news? You don’t actually need one. With two simple measurements and a little bit of proven math, you can estimate your horse’s weight with surprising accuracy. Here is exactly how to do it.
What You’ll Need
You don’t need to buy any fancy equipment for this. Just go grab:
- A soft fabric measuring tape (the kind used for sewing).
- No tape? No problem: If you don’t have a fabric tape long enough, just use a long piece of baling twine or soft rope. Mark the length on the string, and then lay it flat against a regular metal tape measure to get your numbers.
One quick tip before you start: Make sure your horse is standing perfectly square on a flat, level surface. (Easier said than done, I know!) If they are resting a hind leg or standing on a slope, their body shifts, which will totally skew your measurements.
Step 1: Finding the Heart Girth
The “heart girth” is just the circumference of your horse’s barrel, measured right behind their front legs.
- Stand on the near (left) side of your horse.
- Drape your measuring tape over their back, right over the highest point of the withers.
- Reach under their belly and catch the other end of the tape, bringing it up right behind their elbows. (Basically, it should sit exactly where your saddle’s girth would normally go).
- Pull the tape snug. You want to compress their hair coat just a little bit, but don’t pull it so tight that it digs in!
- Write down that number in inches.
Step 2: Measuring Body Length
Here is where a lot of well-meaning owners accidentally make a mistake! You are not measuring from the front of the chest to the tail. Instead, you need to measure from bone to bone.
- Find the point of the shoulder. This is that hard, bony bump at the very front of your horse’s shoulder area.
- Find the point of the buttock. This is the bony bump all the way at the back of their hindquarters, right beside their tail.
- Stretch your tape in a straight, horizontal line from the point of the shoulder directly to the point of the buttock. (Pro tip: Having a barn friend hold one end makes this about ten times easier!)
- Write down that number in inches.
The Math Behind the Magic
Once you have your Heart Girth and Body Length, you can plug them into a tried-and-true equation known as the Carroll & Huntington formula.
It looks like this: Weight in lbs = (Heart Girth² × Body Length) / 330
Equine researchers have used and tested this formula for decades. While it is technically an estimation, vets widely consider it accurate enough for general medication dosing and managing your horse’s diet.
Skip the Math: Let Us Do the Work!
Look, you’re at the barn to spend time with your horse, not to do algebra.
Now that you have your two measurements, just click to here to use our Interactive Equine Weight Calculator. Type in your Heart Girth and Body Length, and our tool will instantly do the math for you. It will even tell you exactly how much forage your horse should be eating every day, and the maximum rider weight they can comfortably carry.
Grab your measuring tape, go give your horse a pat, and let our calculator handle the rest!
