How to Use a Horse Weight Tape

What you need

A commercial weight tape, or an ordinary soft tailor’s tape plus the weight calculator.
Level, reasonably hard ground — a slope or deep bedding changes the reading.
Ideally a second pair of hands, or a horse that stands quietly.
A note of the date and both measurements, so you can compare next month.

The method, in order

Stand the horse square. All four feet on level ground, weight evenly distributed, head in a normal relaxed position — not stretched up for a treat.
Find the girth groove. The tape goes around the barrel just behind the elbow, and across the lowest point of the withers.
Have the horse exhale. Watch the ribs. Slide the tape through your fingers as the horse breathes out, then read at the bottom of the breath.
Pull snug, not tight. The tape should sit against the coat without compressing it. If you can slide a finger under it easily, it is too loose.
Note the girth figure. Read at eye level to avoid parallax error.
Measure the length. From the point of the shoulder to the point of the buttock, in a straight line, not following the curve of the body.
Repeat both. Take each measurement twice. If they differ by more than half an inch, take a third.
Record it. Date, girth, length, computed weight, and condition score.

The five mistakes that skew the result

Mistake	Effect on the estimate
Measuring at the inhale	Overstates weight — the chest is at its largest
Running the length tape along the body’s curve	Overstates length, and weight, often by 5–10%
Pulling the tape tight enough to compress the coat	Understates girth, and girth is squared — so the error doubles
Using the wrong divisor for the animal	Ponies, yearlings and weanlings need 299, 301 and 280 rather than 330
Mixing units between the two measurements	A girth in centimetres with a length in inches produces nonsense

Note how heavily girth is weighted: because it is squared, a half-inch error in girth moves the final weight more than a half-inch error in length. Take the girth reading twice.

Set up a monthly routine

The value of a weight tape is not a single reading — it is a trend. Measure on the same day each month, at the same time of day, before feeding, and write the number down. A steady 10 lb per week in either direction is a signal long before the horse looks different.

Pair the weight with a body condition score: weight alone cannot tell you whether the change is muscle, fat, or a full gut. Together they answer the two questions that matter — how heavy, and is that right.

Frequently asked questions

Where do you put a weight tape on a horse?

Around the barrel, just behind the elbow and across the lowest point of the withers — the same place a girth sits. Read it at the end of a normal exhale.

Can I use a normal tape measure instead of a weight tape?

Yes. A commercial weight tape simply converts girth into a printed weight. With a soft tailor’s tape you take the girth and length figures and enter them into a calculator that applies the same formula.

How often should I weigh my horse?

Monthly is enough for a stable adult, every two weeks while you are correcting condition, and weekly for a horse on a weight-loss or weight-gain programme.

Which measurement matters more, girth or length?

Girth. It is squared in the formula, so a small error in the girth reading has roughly twice the effect of the same error in length.

Related tools and guides

Sources and method

Ontario Ministry of Agriculture, Food and Rural Affairs — Estimating body weight for horses.
NSW Department of Primary Industries — Primefact 928: Estimating a horse’s condition and weight.
Carroll, C.L. & Huntington, P.J. (1988) — the girth-and-length body weight formula used on weight tapes.

Page last reviewed 2026-10-16. Results are estimates from published formulas and are not veterinary advice.