Dog harness, collar and lead size calculator
Updated 14 October 2026
In short: to choose a harness size, measure the chest girth (just behind the front legs); for a collar, the neck girth; for a lead, look at the weight. Enter these measurements in the calculator below: it compares them with the Goofy Goldens size guide and gives you the Confort harness, collar and lead size, with tips for your dog's build.
Size calculator: harness, collar and lead
Fill in what you have: chest girth is enough for the harness, neck girth for the collar and weight for the lead. Breed is optional and only fine-tunes the advice.
Find the right size in 30 seconds
Based on the official Goofy Goldens size guide (measurements in cm; 1 in = 2.54 cm)
Indicative result: confirm with the size guide on each product page. Not sure? Write to us, we're happy to help.
How to measure your dog in 2 minutes
- Get a soft tape measureA sewing tape and a few treats. Your dog should be standing and relaxed.
- Chest girthWrap the tape around the widest part of the ribcage, just behind the front legs. Snug, not tight. This is the measurement that decides the harness size.
- Neck girthAt the base of the neck, where a collar sits, with two flat fingers slipped under the tape.
- WeightWeigh yourself holding your dog, then without, and subtract. It helps choose the lead and decide between two sizes.
Tip: measure twice and keep the average. On a long-haired dog, press lightly to feel the body under the coat. Write your measurements down: you'll reuse them for every purchase. Step-by-step method: how to find the right harness size.
How to read the result
For the harness, the calculator starts from the chest girth, because the chest strap holds the dog and takes the pulling force. Neck girth and then weight decide between two sizes when their ranges overlap. For the collar, only neck girth counts. For the lead, weight guides the width.
You should add 2 or 3 cm to the chest girth.
FALSEWith our calculator, enter the real measurement, taken without squeezing. Our size ranges already include the harness's adjustment range.
Breed is enough to pick the size.
FALSENo. Two Labradors can differ by 10 cm in chest girth. Breed gives an idea; the measurement decides.
A dog can wear an L harness and an M collar.
TRUEYes, the harness and collar charts don't line up. That's why the calculator handles each item separately.
Between two sizes, always take the bigger one.
IT DEPENDSFor a growing puppy, the size up lasts longer. For a slim adult, the size down stops the harness twisting. The calculator picks the size where your dog sits closest to the middle of the range.
The result flags something odd
If the neck girth is outside the recommended harness range, or the neck is bigger than the chest, measure again: the numbers may be swapped. Some builds also fall outside standard charts: very deep chests (sighthounds, Dobermanns) or very broad ones (Bulldogs, Staffies). Send us your measurements and a side photo, and we'll reply personally.
The Goofy Goldens size guide
These are the charts the calculator uses. They match our size guide and the tables on each product page.
| Size | Chest girth | Neck girth | Weight | Examples |
|---|---|---|---|---|
| XS* | 28â38 cm | 25â38 cm | 2â5 kg | Chihuahua, Yorkshire Terrier |
| S | 41â54 cm | 35â44 cm | 5â10 kg | Jack Russell, Cavalier King Charles |
| M | 46â61 cm | 39â51 cm | 10â18 kg | Beagle, French Bulldog, Cocker Spaniel |
| L | 57â83 cm | 42â56 cm | 18â32 kg | Golden Retriever, Border Collie, Malinois |
| XL | 59â88 cm | 48â63 cm | 32â45 kg | German Shepherd, Beauceron, Bernese Mountain Dog |
* XS is available on some Confort models: check the product page.
| Size | Fabric collar | Waterproof collar | Guide weight |
|---|---|---|---|
| S | 28â43 cm | 27â36 cm | 5â10 kg |
| M | 33â51 cm | 32â47 cm | 10â25 kg |
| L | 41â66 cm | 42â63 cm | over 25 kg |
Neck girth. See our dog collars.
| Model | Dimensions | For |
|---|---|---|
| Classic lead M | 150 cm, 2 cm wide | Small and medium dogs (under about 18 kg) |
| Classic lead L | 150 cm, 2.5 cm wide | Large dogs (18 kg and over) |
| Multi-position lead | 250 cm, 2.5 cm wide | Medium to large dogs, hands-free or across the body |
See our dog leads.
The breeds listed are examples: your dog's measurements always beat its breed.
Which size for your dog's profile?
Changes size within weeks
Pick a size where it sits at the low end of the range, measure again every two to three weeks and check the fit before each walk. See our puppy harness guide.
Broad chest for its weight
Bulldogs, Pugs, Boxers: trust the chest girth rather than the weight, and use a harness rather than a collar for walks.
Deep chest, narrow waist
Often between two sizes. Chest girth is still the guide, and a harness stops it slipping out of a collar.
Often gains weight
A thin dog often fills out in the first months. Measure again after a few weeks and adjust the straps.
Once the right size arrives, fitting makes all the difference: follow our guide to adjusting your dog's harness. To see how it looks before ordering, try our harnesses on a photo of your dog with the Dog Studio.
5 things to remember
- Always measure your dog rather than relying on its breed or previous size.
- Harness: chest girth first. Collar: neck girth.
- Between two sizes, aim for the one where your dog sits in the middle of the range.
- Check the fit with two flat fingers under each strap.
- Measure again for a puppy, a dog that gains or loses weight, or changes coat.
Frequently asked questions
Should I add a few centimetres to the chest measurement?
No. Enter the real measurement, taken without squeezing: our size ranges already match the harness's adjustment range. Just avoid a size where your dog sits at the very edge.
My dog is between two harness sizes, which should I choose?
The one where its measurement is closest to the middle, which is what the calculator suggests. For a growing puppy, the size up lasts longer; for a slim adult, the size down stops the harness twisting.
Are collar and harness sizes the same?
Not necessarily. A dog can wear an L harness and an M collar, because the charts don't line up.
Which lead width should I choose?
2 cm for a dog under about 18 kg: light, and the clip doesn't weigh on the harness. Above that, 2.5 cm for a better grip. For length, read our article on the ideal lead length.
My measurements are in inches, what do I do?
Multiply by 2.54: 20 inches is about 51 cm. The calculator works in centimetres.
What if the size I receive doesn't fit?
Write to us: a size exchange is possible under our returns policy. Keep the product clean and with its tags while you try it.