How to Measure Your Dog for a Harness: Size Chart and Fit Check
Short answer: measure your dog’s chest at its widest point, just behind the front legs, and the neck where a collar sits. Use a soft tape measure with your dog standing. Compare both numbers with the size chart; if your dog is between two sizes, choose the larger one and tighten the straps until two fingers fit underneath.
A harness that fits well is safer and more comfortable than one that is “nearly right”. Too loose and a dog can back out of it; too tight and it rubs behind the front legs. This guide shows you how to take the two measurements that matter, how to read a size chart and how to check the fit at home in under a minute.
What you need
- A soft tape measure (the kind used for sewing). No tape? Use a piece of string, mark it, then measure the string with a ruler.
- A few treats, so your dog stays still.
- Two minutes, and ideally a second person to hold your dog.
How to measure your dog for a harness, step by step
- Stand your dog on all four legs. A sitting or lying dog gives a smaller chest measurement.
- Measure the chest (girth). Wrap the tape around the widest part of the rib cage, just behind the front legs. Keep it snug against the coat but not tight. Many size charts, including ours, call this measurement “waist”.
- Measure the neck. Wrap the tape around the base of the neck, where a collar would rest, not the thinnest part near the head.
- Measure twice. Write down both readings. If they differ, use the larger one.
- Compare with the chart. The chest measurement decides the size; the neck confirms it.
FreeFaro harness size chart
The Air harness and the H harness use the same sizes. All measurements in centimetres.
| Size | Chest / waist (cm) | Neck (cm) |
|---|---|---|
| XS | 27–37 | 24–28 |
| S | 40–53 | 30–40 |
| M | 48–66 | 41–54 |
| L | 58–86 | 52–65 |
The no-pull harness (S to L) and the Force harness for medium and large dogs (M to XL) have their own charts on each product page.
Between two sizes?
Choose the larger size. An adjustable harness can always be tightened, but it cannot be made bigger. The ranges overlap on purpose: a dog with a 50 cm chest fits both S and M, so the neck measurement or your dog’s build decides. A deep-chested dog with a slim neck usually suits a fully adjustable H harness.
The two-finger fit check
Put the harness on and adjust every strap. Then check:
- Two fingers slide flat between any strap and your dog’s body. One finger is too tight; a whole hand is too loose.
- No rubbing behind the front legs. The strap should sit a few centimetres behind the armpits.
- The neck strap rests on the chest bone, not on the throat.
- Your dog cannot back out. Walk backwards slowly with the leash attached; the harness should stay on.
Check the fit again after the first walks: webbing settles and coats change with the seasons.
Common mistakes
- Choosing by weight or breed alone. Two dogs of the same weight can have very different chests. Measurements are always more reliable.
- Measuring over a thick winter coat and then using the harness in summer, or the other way round.
- Buying a big harness for a puppy to grow into. A loose harness is easy to escape from. Buy the size that fits now and measure again every few weeks while your puppy grows.
- Using the collar size. A collar only tells you the neck; a harness is sized by the chest.
Measuring a cat for a harness
The method is the same: chest just behind the front legs, and the base of the neck. Cat harnesses need a snugger fit, because cats are flexible and quick to wriggle out.
| Cat harness size | Chest (cm) | Neck (cm) |
|---|---|---|
| S | 25–40 | 15–30 |
| M | 35–55 | 15–30 |
See our cat harness and leash sets.
Frequently asked questions
Can I choose a harness size by my dog’s weight?
Only as a rough guide. Chest girth is what decides whether a harness fits, so always measure.
My dog is between two sizes. Which one should I buy?
The larger one, then tighten the straps until two fingers fit underneath.
How do I know if the harness is too tight?
If you cannot slide two fingers under the straps, if it leaves marks on the coat or if your dog walks stiffly, loosen it or go up a size.
Is collar width related to harness size?
No. FreeFaro dog collars come in four widths, from 1 cm (XS) to 2.5 cm (L), chosen by your dog’s size and neck measurement.
What if the size is wrong?
FreeFaro Europe accepts returns within 30 days, so you can exchange for the right size.
Ready to choose?
With your two measurements in hand, pick the harness that suits how your dog walks: Air for everyday comfort, H for a fully adjustable fit, no-pull for dogs that pull. Every harness comes in the same prints as our leashes and collars, so the set matches. Orders ship from Viseu, Portugal, in 1–2 business days.
Written by the FreeFaro Europe team, official importer of FreeFaro in Europe. Size data from FreeFaro product specifications.
