The 30-second version
- Use a soft tape measure in centimetres, with your dog standing square on a level floor.
- Chest girth (for harnesses and coats): around the widest part of the ribcage, just behind the front legs1.
- Neck: around the base of the neck, at its lowest point1.
- Back length (for coats): from the base of the neck to the base of the tail.
- Keep the tape flat and snug, not tight. Measure twice1.
- Crate: length from nose to base of tail (standing) and sitting height to the top of the head or ear tips, then add about 10 cm to each2.
What you need
- A soft tailor's tape measure. No tape? Use a long piece of string, mark it, and measure the string against a ruler or metal tape afterwards1.
- Small, tasty treats, to keep your dog standing still and happy.
- A helper if you can. One person holds and treats, the other measures.
- Bathroom scales for weighing (or your vet practice's scales for a big dog).
- Something to write on, or the [measurement record](#record) at the bottom of this page.
Getting your dog ready
- Pick a calm moment, such as after a walk, not when your dog is excited to go out.
- Take off any harness, coat or bulky collar. They change the reading.
- Stand your dog on a level, non-slip floor with all four feet squarely underneath it and the head up in a natural position. A sitting or lying dog's chest, back and coat change shape and give the wrong numbers.
- Keep sessions short. Measure one thing, give a treat, then do the next.
- If your dog is worried about being touched or about the tape, stop. Show the tape, treat; touch it to the dog's side, treat; build up over a few days. A rushed, wriggling measurement is usually wrong anyway.
Chest girth: the one that matters most
Chest girth (the distance around the body) decides the size of almost every harness and most dog coats. Get this one right and you've done most of the work.
- Find the spot: the widest part of the ribcage, just behind the front legs1. Run your hand back from the elbow and you'll feel the ribs widen out.
- Pass the tape under the chest and bring both ends up to meet on top of the back.
- Check the tape is straight and level all the way round, not slanting back towards the waist, and not twisted.
- Pull it snug so it sits against the body without squeezing: snug, "without being too tight or baggy", as Julius-K9 puts it3. On a fluffy dog, push the tape through the coat to the body.
- Read the number where the end of the tape meets the rest of it. Write it down in centimetres.
- Measure again. If the two readings differ, use the larger one.
Where each brand measures the chest
| Brand | Measuring point |
|---|---|
| Julius-K9 | A set distance behind the front legs that depends on the size: two finger-widths for Baby 1 and 2, three for Mini-Mini and Mini, four for size 0 and up. Measure at the finger furthest from the legs3. |
| Ruffwear | Around the widest part of the chest, just behind the front legs1. |
| Other brands | Most use the widest part of the chest behind the front legs. Always read the brand's own measuring note, because a few measure somewhere else. |
Neck
- Measure around the base of the neck, at its lowest point, where it meets the shoulders1. That is where the neck strap of a harness sits.
- For a collar, measure a little higher up, where the collar will sit. Check the brand's chart to see whether it wants the neck size exactly or has already added room.
- Overhead harnesses must also go over the head. If your dog has a broad head (bull breeds, for example), check that the neck opening at its largest will pass over it.
Back length
You'll need this for dog coats, and it helps check whether a vest-style harness suits a long-backed dog.
- Measure along the spine from the base of the neck, where a collar sits, to the base of the tail, where the tail joins the body. Don't include the tail.
- Keep your dog's head up and straight. A dog looking down or round at you stretches or shortens its back.
- Coat makers don't all measure back length the same way. Some measure to the base of the tail, some to where the coat should end. Check the chart before you compare.
Height at the shoulder
This is the height breed standards quote. It's useful for comparing your dog with its breed and for some beds. For a crate, you need sitting height instead (see F below).
- Stand your dog next to a wall on a level floor.
- Find the withers: the highest point of the shoulder blades, just behind the neck.
- Lay a book or ruler flat across the withers so it touches the wall, and mark the wall where its underside meets it.
- Measure from the floor to the mark.
Nose-to-tail length
The main measurement for crates and beds.
- With your dog standing, measure in a straight line from the tip of the nose to the base of the tail.
- Stop at the base of the tail, where it joins the body. Don't include the tail2.
- For a crate, add space on top of this so your dog can stretch out. UK guides suggest adding 5–10 cm2, and Pet Crates Direct suggests about 6 inches (15 cm)4. We suggest about 10 cm.
Sitting height
The second crate measurement, and the one most people forget.
- Ask your dog to sit on a level floor, head up in a natural position.
- Measure from the floor to the top of the head. If your dog's ears stand up, measure to the tips of the ears2.
- Measure sitting, not standing: some dogs are taller when they sit2.
- Add about 10 cm, as for length. Your dog should be able to sit up in the crate without its head or ears touching the top5.
Choosing a crate size from your numbers
- Compare your dog's length and sitting height, each plus about 10 cm, with the crate's length and height. The crate has to clear both.
- Check the width too. The RSPCA says a crate should be big enough for your dog to stand, turn around, lie down and stretch6; Dogs Trust adds sitting down, wagging its tail and stretching out fully7.
- Crates are usually sold by length in inches (24, 30, 36, 42, 48). A "36-inch" crate is about 91 cm long, but brands round differently, so check the real dimensions.
- Check whether a brand lists inside or outside measurements. Plastic and furniture-style crates can be noticeably smaller inside than out.
- For a puppy, many owners buy the adult size and use a divider panel to make it smaller at first. See the puppy section of any of our crate guides.
- For the car, measure your boot too: floor length and width, and the height of the opening. The Highway Code says dogs must be suitably restrained in a vehicle8.
Crate guides by breed
- BeagleCrate size guide
- Bichon FriseCrate size guide
- Border CollieCrate size guide
- Border TerrierCrate size guide
- BulldogCrate size guide
- Cavalier King Charles SpanielCrate size guide
- CavapooCrate size guide
- ChihuahuaCrate size guide
- CockapooCrate size guide
- Cocker SpanielCrate size guide
- English Springer SpanielCrate size guide
- French BulldogCrate size guide
- German Shepherd DogCrate size guide
- Golden RetrieverCrate size guide
- Jack Russell TerrierCrate size guide
- Labrador RetrieverCrate size guide
- Miniature DachshundCrate size guide
- Miniature SchnauzerCrate size guide
- PugCrate size guide
- Shih TzuCrate size guide
- Staffordshire Bull TerrierCrate size guide
- Standard DachshundCrate size guide
- WhippetCrate size guide
- Yorkshire TerrierCrate size guide
Weight
Some brands give weight ranges as a second guide, and weight helps you track a growing puppy.
- Weigh yourself on bathroom scales. Then weigh yourself holding your dog. Take the first number from the second.
- For a dog too big to lift, ask your vet practice: many let you pop in and use their scales.
- For a small puppy, place a box or basket on kitchen scales, zero it, and put the puppy in.
- Weigh at about the same time of day each time, ideally before a meal, so readings are comparable.
Inches and pounds
UK and European brands mostly use centimetres and kilograms. If your tape or scales use imperial units, convert first: inches × 2.54 = centimetres and pounds × 0.4536 = kilograms.
= – cm
= – kg
Puppies, fluffy dogs and other special cases
Puppies
Size a puppy on its measurements today, not on what you expect it to reach1. Research on millions of pet dogs shows small breeds reach adult weight sooner than large ones, and large breeds can keep growing into their second year9.
We suggest measuring the chest every two weeks while your puppy is growing fast, then monthly until the numbers stop changing. If you can no longer slide two fingers under the harness straps, measure again.
Fluffy and double-coated dogs
Press the tape through the coat until it sits against the body. A tape resting on the fluff can read several centimetres too big.
Measure again after grooming or clipping, and adjust the harness: less coat means a looser fit. Our Cockapoo and Golden Retriever guides go into more detail.
Deep-chested and barrel-chested dogs
Dogs such as Staffies, French Bulldogs and Labradors have a chest that is big for their weight. Always size these breeds by chest girth, not weight. See our Staffordshire Bull Terrier guide for an example.
Flat-faced (brachycephalic) dogs
Keep the tape and any strap well clear of the throat. The RSPCA advises walking flat-faced dogs on a harness rather than a collar to avoid pressure on the neck10.
Long-backed dogs
Measure the chest level with the ground, not at a slant, and take the back length too so you can check vest-style harnesses aren't too short. See our Dachshund guide.
Wriggly dogs
Use string: loop it round, pinch the point where it meets, and measure the string afterwards1. It's quicker than reading a tape on a moving dog. A helper feeding treats at nose height keeps most dogs standing.
Older or stiff dogs
Measure in short goes and let your dog rest in between. If standing seems uncomfortable for your dog, check with your vet.
Common measuring mistakes
| Mistake | What happens | Fix |
|---|---|---|
| Measuring the neck for a harness | The harness is too small around the body | Harness sizes go by chest girth |
| Tape resting on top of a fluffy coat | A size too big; it slips | Push the tape through the coat to the body |
| Tape pulled tight | A size too small; it rubs | Snug, flat, not squeezing |
| Tape slanting back towards the waist | Reading too small | Keep the tape level, just behind the front legs |
| Measuring a sitting or lying dog | Wrong chest and back readings | Measure standing square |
| Measuring in inches, reading a chart in cm | Wildly wrong size | Convert: inches × 2.54 = cm |
| Going by weight alone | Wrong size for deep-chested breeds | Use weight only as a tie-breaker |
| Using last season's measurements for a puppy | Too small | Re-measure before every purchase |
| Measuring a dog standing for crate height | Crate too low to sit up in | Measure sitting, to the top of the head or ear tips |
| Including the tail in crate length | Crate bigger than needed | Measure to the base of the tail |
| Comparing a crate's outside size with your dog | Crate tighter than expected | Check the inside dimensions |
From numbers to the right size
- Compare your dog's chest in centimetres with each brand's chart, not the size letters. A Medium in one brand can be a Large in another.
- Brand charts often overlap, so your dog may fit two sizes. Choose the size where your measurement sits nearer the middle, so the harness can adjust either way.
- If your dog is fully grown and right on the border between two sizes, Ruffwear recommends choosing the larger size11.
- Julius-K9 gives weight ranges as well as chest ranges; use weight to decide between two sizes that both fit the chest3.
- Or let our size finder do it: pick the breed, enter the chest and weight, and it shows the size in each brand.
Harness guides by breed
- BeagleHarness size guide
- Bichon FriseHarness size guide
- Border CollieHarness size guide
- Border TerrierHarness size guide
- BulldogHarness size guide
- Cavalier King Charles SpanielHarness size guide
- CavapooHarness size guide
- ChihuahuaHarness size guide
- CockapooHarness size guide
- Cocker SpanielHarness size guide
- English Springer SpanielHarness size guide
- French BulldogHarness size guide
- German Shepherd DogHarness size guide
- Golden RetrieverHarness size guide
- Jack Russell TerrierHarness size guide
- Labrador RetrieverHarness size guide
- Miniature DachshundHarness size guide
- Miniature SchnauzerHarness size guide
- PugHarness size guide
- Shih TzuHarness size guide
- Staffordshire Bull TerrierHarness size guide
- Standard DachshundHarness size guide
- WhippetHarness size guide
- Yorkshire TerrierHarness size guide
Checking the fit when it arrives
- You should be able to slide two fingers flat under every strap, and no more11.
- The strap around the body sits a little way behind the front legs, not pressed into the "armpit".
- Nothing presses on the throat.
- Your dog's stride looks the same with and without the harness. A small study found harnesses can shorten how far the shoulder reaches forward12.
- After the first few walks, check behind the front legs and under the chest for redness or rubbed fur. If the skin is sore, stop using the harness and ask your vet.
Measurement record
Print this page or copy the table to keep track, especially for a growing puppy.
| Date | Chest (cm) | Neck (cm) | Back (cm) | Height (cm) | Length (cm) | Sitting (cm) | Weight (kg) |
|---|---|---|---|---|---|---|---|
Questions about measuring
How do I measure my dog for a crate?
Measure length from the nose to the base of the tail with your dog standing, and sitting height from the floor to the top of the head or ear tips2. Add about 10 cm to each and compare with the crate's length and height.
Where exactly do I measure my dog for a harness?
Should the tape be tight or loose?
Snug against the body, flat and untwisted, but not squeezing: "without being too tight or baggy"3. On a fluffy dog, push the tape through the coat to the body.
Can I measure my dog with string?
Yes. Wrap the string round, pinch where it meets, then measure the string against a ruler or tape1.
How do I convert inches to centimetres?
Multiply inches by 2.54. For pounds to kilograms, multiply by 0.4536. Or use the converter on this page.
How often should I measure my puppy?
We suggest every two weeks while it is growing fast, then monthly until the measurements stop changing. Always buy for its size today1.
Is weight or chest size more important for a harness?
Chest girth. Weight is only a rough guide because dogs of the same weight can have very different chests. Use weight as a tie-breaker when the chest fits two sizes3.
My dog won't stand still. What can I do?
Measure after a walk, use a helper with treats at nose height, and try the string method. Keep sessions short and stop if your dog is worried.
Why is my dog a different size in different brands?
Each brand designs its own sizes and chest ranges, and many overlap. Always compare your dog's measurement in centimetres against each chart.