What Size Harness Does My Dog Need? (Fit Guide 2026)
Dog LoveWhat size harness does my dog need? Measure, fit, check.
Most harness problems we see in the salon, the rubbing, the matting, the dog who backs straight out at the vet, come down to fit rather than the harness itself. This guide covers how to measure properly, how to read a size chart, how to fit every strap, the checks that tell you it is right, and when to measure again.
Chest first, size up if unsure, then fit every strap
- Measure the widest part of the chest, just behind the front legs
- Press the coat flat; fluff adds centimetres
- Between two sizes, take the larger and tighten it
- Two flat fingers under every strap, no more
- Girth strap a few finger widths behind the armpit
- Recheck after every groom and every growth spurt
In this guide
How to measure your dog for a harness
You need a soft sewing tape, a few treats and about two minutes. A string and a ruler work if you have no tape.
- Stand your dog square.All four feet on the floor, head up, not sitting. A sitting dog's chest measures differently.
- Find the widest part of the ribcage.It is just behind the front legs, where the chest is deepest. On most dogs that is about a hand's width behind the elbow.
- Press through the coat.Push the tape down to the skin. On a fluffy oodle or a long coated breed, measuring over the fluff can add five centimetres or more and put you a whole size out.
- Snug, not tight.The tape should sit flat against the body without squeezing. Read the number where the tape meets.
- Do it twice.If the two readings differ, use the larger one.
Reading a harness size chart
Every brand sizes differently. A Medium in one brand can be a Large in another, so always go by the centimetres, never the letter.
| Size | Chest | Price |
|---|---|---|
| XS | 33 to 43cm | $59.95 |
| S | 43 to 56cm | $61.95 |
| M | 56 to 69cm | $64.95 |
| L | 69 to 81cm | $69.95 |
| XL | 81 to 107cm | $74.95 |
Take the larger one
A harness that is a little generous and tightened down sits flat and stays kind to the skin. One that is a little tight rubs on every walk and cannot be fixed by adjusting. The four adjusters on each size give plenty of room to bring a bigger size in.
Why we never size by kilos
A slim 20kg Border Collie and a barrel chested 20kg Staffy can sit two sizes apart. Weight tells you very little about the shape of a chest, which is the only thing a harness cares about.
Typical chest measurements for breeds we groom often
A starting point only. Individual dogs vary a lot, and the tape always wins.
| Breed | Typical chest | Usual size |
|---|---|---|
| Toy Cavoodle | 38 to 48cm | XS or S |
| Mini Cavoodle | 45 to 58cm | S, sometimes M |
| Toy Spoodle | 38 to 46cm | XS or S |
| Mini Spoodle | 44 to 56cm | S |
| French Bulldog | 50 to 65cm | S or M |
| Mini Groodle | 48 to 62cm | S or M |
| Mini Labradoodle | 52 to 62cm | S or M |
| Medium Groodle or Labradoodle | 60 to 72cm | M or L |
| Standard Groodle | 70 to 88cm | L or XL |
| Standard Labradoodle | 70 to 95cm | L or XL |
| British Bulldog | 75 to 90cm | L or XL |
Each breed has its own guide with the coat and shape details that change the fit: Cavoodles, Spoodles, Groodles, Labradoodles and French Bulldogs.
Fitting a harness strap by strap
A new harness arrives at a generic setting. Spending five minutes adjusting it is the difference between a harness that works and one that rubs.
- Loosen everything first.Open all four adjusters a little so nothing is tight while you put it on.
- Put it on.Either unclip the neck, wrap it around and clip it shut, or slip it over the head if your dog is relaxed about that. Then buckle the belly strap behind the front legs.
- Set the neck strap.It should sit low, across the base of the neck and top of the chest, not up near the throat like a collar.
- Centre the chest plate.The padded panel belongs flat on the breastbone, between the front legs. If it sits off to one side, even out the left and right adjusters.
- Set the girth strap.Tighten the belly strap so it sits a few finger widths behind the armpit, never wedged into the crease, which is where most rubbing and matting starts.
- Go round again.Tightening one strap changes the others. Do one more pass of all four.
Five checks that tell you the fit is right
Do these in the house before the first walk, and again after the first week.
- The two finger check.Two flat fingers should slide under every strap. Three fingers means too loose; struggling to fit one means too tight.
- The breastbone check.Clip on the lead and give a gentle forward pull from the front ring. The chest plate should stay on the breastbone, not ride up toward the throat.
- The armpit check.Slide a finger along the strap behind the front leg. You should have clear space between the strap and the crease of the armpit.
- The twist check.Walk your dog a few laps of the room. The harness should stay centred, not rotate round to one side.
- The reverse check.Hold the lead and gently encourage your dog to step backwards. If the harness starts sliding forward over the shoulders, tighten the girth strap. Our guide on stopping a dog backing out of a harness covers escape artists in detail.
How a badly fitted harness shows up on the grooming table
We see the results of fit every day. These are the signs to look for at home.
Pink skin and bald stripes
Thinning hair or redness behind the elbow, across the chest or on top of the shoulders means a strap is rubbing. Usually it is too tight, too far forward, or worn too long.
Felted mats along the strap lines
A strap width band of mats behind the front legs or across the breastbone is friction plus trapped moisture. Our guide to harness rubbing under the arms shows exactly where to check.
Twisting and riding up
A harness that rotates to one side or slides up into the throat when your dog pulls is too loose or the wrong shape. Our guide on a harness that keeps twisting covers the fixes.
A shortened stride
If your dog walks differently in the harness, shorter steps at the front or reluctance to move, a strap may be sitting across the shoulder joint. Loosen, refit, and see your vet if it continues.
The fit changes more often than people expect
A harness that was perfect in autumn can be wrong by spring. Four things change it.
- Grooms.A full groom can take several centimetres of coat off the chest. Refit the straps before the first walk after every groom.
- Puppy growth.Fit the chest your puppy has today, not the one you expect. A harness bought to grow into slides around and rubs. Check the fit every week or two and size up when two fingers no longer slide under the straps.
- Weight.A kilo gained over winter changes the girth, especially on deep chested breeds. Run the tape around a couple of times a year.
- Seasonal coats.A thick winter coat or a summer clip both change the setting. Adjust the straps rather than living with a harness that is suddenly loose or snug.
Harness sizing questions
How do I measure my dog for a harness?
Stand your dog square, wrap a soft tape around the widest part of the ribcage just behind the front legs, press it through the coat to the skin, and read the number. Measure twice and use the larger reading.
How tight should a dog harness be?
Snug enough that it does not twist or slide, loose enough that two flat fingers slide under every strap. If you can fit three fingers it is too loose; if one is a struggle it is too tight.
What if my dog is between sizes?
Choose the larger size and tighten the adjusters. A slightly generous harness brought in sits flat; a slightly small one rubs and cannot be loosened enough to fix it.
Should I buy a bigger harness for my puppy to grow into?
No. Fit the chest your puppy has now. A harness that is too big slides around, rubs and is easy to back out of. Check the fit every week or two and size up when you need to.
Can I use my dog's weight to choose a size?
Not reliably. Dogs of the same weight can have very different chests. Use the chest measurement every time.
Do I need to adjust the harness after a groom?
Yes. A groom can take a surprising amount of coat off the chest, leaving the straps loose. Refit before the first walk after every groom.
Where should the strap behind the front legs sit?
A few finger widths behind the armpit, on the ribcage. Wedged into the crease of the armpit, it rubs the skin on short coats and mats long coats.
What if I order the wrong DogLove Pro size?
Exchange it within 30 days, as long as it is unused and in its packaging. Drop it at our Tranmere salon for free, or post it back at your cost, and we send the new size at no charge.