How do you measure a small dog for a well-fitting harness?

You've bought a harness, put it on, and it's immediately crooked. Too loose at the shoulders, too tight behind the front legs, or it constantly slides forward as soon as your dog starts walking. Familiar, right? For small dogs, the margin for a good fit is particularly narrow, and most size charts don't account for this enough.

A poorly fitting harness is more than just an annoyance. It can restrict movement, irritate the skin, or even chafe on active dogs. And for small breeds like a Maltipoo, Bichon, or Cavapoo, their build is compact and sensitive: narrow rib cage, soft skin, a short torso. This requires precision when measuring, not a guess based on weight.

Three measurements that really matter

Most brands ask for the chest circumference. This is the measurement you take just behind the front legs, at the widest point of the rib cage. Measure with a flexible tape measure, not too tight and not too loose. You want room for one to two fingers between the tape and your dog's skin. Note this measurement, as it is your basic data.

The second measurement is the neck circumference, measured where a collar would sit. Not too high, not too low. Some harnesses have an adjustable neck opening, but it is still important to know if your dog is built narrow or wide here.

The third measurement that few people take but makes a big difference is the back length. Measure from the base of the neck, the point where the neck and back meet, to the beginning of the tail. For small dogs with a compact torso, this can be the deciding factor between a harness that stays nicely in place and one that constantly slides forwards or backwards.

How to measure this most easily?

Have your dog stand calmly on a flat surface, preferably not when they are excited. A small treat after measuring helps keep the mood good. Use a soft tailor's tape measure, or failing that, a piece of string that you then lay next to a ruler. Write down all three measurements before you start comparing.

Also know that two dogs of the same breed and the same weight can look very different in terms of measurements. One Maltipoo has a wide rib cage and a short back, the other is narrow and elongated. Measurements say more than weight, always.

What else you should check on the size chart

Many brands give a range: size S fits a chest circumference of 30 to 40 centimeters, for example. If your dog is exactly in the middle, choose that size without hesitation. If you are at the limit, always choose the larger size and then adjust the harness. A harness that is just too small can never be adjusted properly. One that is slightly roomier can.

Also check how adjustable a harness is. Cheaper models often only have one adjustment ring, while a well-fitting harness for a small dog should be adjustable at at least two points: at the neck and at the chest. This way, you can fine-tune the fit to your dog's specific build.

After putting it on

A well-fitting harness moves with your dog, not for her. Your dog must be able to stretch her front legs freely forward without the harness pulling up in the armpits. There should be no room to slip out, but also no pressure on the soft skin behind the front legs. The two-finger test also applies here: put two fingers under the harness on the chest and on the back. If that works comfortably, then it fits well.

Holy Moly will soon be launching a collection of harnesses for small dogs, designed with precisely these things in mind.