How to measure your horse's weight at home
You don't need a weighbridge to keep track of your horse's weight. A soft tape and two measurements will give you a useful estimate in a couple of minutes. Here is exactly where to put the tape, how to turn the numbers into kilograms, and the mistakes that make the result unreliable.
The short version
- Measure the heart girth and the body length, standing square on level ground.
- Weight in kg is girth squared, times length, divided by about 11,900 (all in centimetres).
- Expect an accuracy of about plus or minus 6%. It is best for spotting change over time.
- Use a livestock scale when you need a precise figure, and never dose medication from an estimate.
What you need
- A soft tape measure, like a tailor's tape, in centimetres or inches. A purpose-made weight tape works too, but a plain soft tape lets you take both measurements.
- A helper to hold the horse and the end of the tape. It is much easier with two people.
- Somewhere flat and level, such as a yard or a concrete aisle, so the horse can stand square.
- A note on your phone or in a notebook for the numbers and the date.
Step by step
1. Stand your horse square
All four feet underneath the horse, weight evenly spread, and the head up and level, not stretched out or dropped to the ground. A horse leaning to one side, or standing on a slope, changes the shape of the barrel and shifts the numbers.
2. Measure the heart girth
Pass the tape around the barrel just behind the elbows and over the highest point behind the withers. The tape should sit flat and level on both sides, with no twist and no sag. Pull it snug without squeezing, and read it at the end of a breath out. The tape marks should meet on the opposite side from where you started.
3. Measure the body length
Hold the end of the tape at the point of the shoulder, the front of the shoulder joint, and run it in a straight line to the point of the buttock, the bony point at the back of the hindquarters. Keep the tape straight rather than following the curve of the body.
4. Work out the weight
The simplest way is to use the free horse weight calculator. Enter both numbers in centimetres or inches, choose a body type, and it returns the weight in kilograms, pounds and stone. If you would like to see the arithmetic, it is below.
Worked example A horse with a heart girth of 185 cm and a body length of 160 cm: 185 × 185 × 160 = 5,476,000, and 5,476,000 ÷ 11,900 = about 460 kg (roughly 1,014 lb, or 72 stone 6 lb).
The divisor of 11,900 comes from published work by Carroll and Huntington (1988). Ponies, cobs and very slim horses carry their weight differently, so the calculator offers adjusted divisors for those body types. Those adjustments are approximate, so treat the result for them as a guide.
Mistakes that throw the number off
- A tape that is too tight or too loose. Snug is right. Pulling hard squashes the coat and the skin and under-reads; letting it sag over-reads.
- A tilted tape. If it runs higher on one side, the girth reads long. Check both sides from behind.
- The wrong spot. The tape needs to sit just behind the elbows, not further back on the belly and not up on the withers.
- A horse that isn't standing square, or has its head up high or low. Both change the shape of the barrel.
- Measuring length along the body. Length is a straight line between two bony points, not the length of the back.
- Changing the method. Different tapes, different helpers and different times of day all add noise. Consistency matters more than perfection.
How accurate is it?
Tape-based estimates are typically within about 6% of the true weight for most horses. On a 500 kg horse that is roughly 30 kg either way. That is too loose to trust for a single precise figure, but it is very good at showing direction. If three readings a month apart creep steadily up or down, something is changing. A single jump between two readings may simply be measuring error, or a full or empty gut.
How often should you measure?
Many owners check every two to four weeks, and more often while managing a horse's weight up or down. Measure at the same time of day, ideally before feeding, using the same tape and the same method, so the readings can be compared fairly. Writing each result down with the date is what turns a number into a trend.
When to use a scale instead
A weighbridge, or a livestock scale at a vet, feed merchant or large yard, is the better choice when you need a precise weight. That includes growing youngsters, horses being brought back from poor condition, and anything involving medication.
Weight is only half the picture
Two horses can weigh the same and look completely different. A heavy horse may be well-muscled and in ideal shape, while another at the same weight is carrying too much fat. That is why it helps to pair the number with a hands-on check of body condition. Our guide Is my horse overweight? Weight vs body condition score shows how to do that, area by area.
Keep every measurement in one place
Equus Metric saves each weight and body condition score, charts the trend, and builds a daily ration around your horse. Try it free for 14 days, then £9.99 a month.
General guidance, not veterinary advice. If you are worried about your horse's weight or condition, speak to your vet.