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Quick answer
An adult Cockapoo usually measures 40–65 cm around the chest and weighs 6–12 kg1.
These are the sizes most adult Cockapoos need. Your dog may differ, so measure to be sure.
Get an exact size for your dogHow a Cockapoo is built, and why it matters for fit
The Cockapoo is a cross between a Cocker Spaniel and a Poodle. Its size depends a lot on the Poodle parent, which can be a Toy, Miniature or Standard Poodle2. That is why Cockapoos range from small lap dogs to dogs bigger than a Cocker.
Cockapoos are not recognised as a breed by the Kennel Club, so there is no official breed standard2. Clubs such as the Cockapoo Club of GB run their own registration schemes3. Our typical range of 40–65 cm and 6–12 kg covers most pet Cockapoos, but Cockapoos with a Standard Poodle parent can be bigger, so measuring matters more for this dog than for any other on our list.
The coat is usually wavy or curly and can be thick. It hides the body shape, and it can mat under straps.
How to measure your Cockapoo, step by step
- Get a soft tape measure, or a piece of string and a ruler. Stand your dog on a level floor with all four feet square underneath it.
- Find the measuring point: the widest part of the ribcage, just behind the front legs4. Julius-K9 asks you to measure a set distance behind the front legs, which depends on the size: two finger-widths for the Baby sizes, three for Mini-Mini and Mini, and four for size 0 and up5.
- Wrap the tape all the way round. Keep it flat and untwisted, snug against the body but not squeezing. Read the number in centimetres where the end meets the tape.
- Measure twice4. If the two readings differ, use the larger one.
- Weigh your dog too. Julius-K9 gives a weight range for every size as a second guide5; the other brands here size by chest only.
Cockapoo measuring tips
- Push the tape through the coat until it sits against the skin, then read it. A tape resting on top of a fluffy coat can easily read a size too big.
- Measure again after every groom. A freshly clipped Cockapoo can be several centimetres smaller around the chest than one due a groom.
- Ask your breeder about the Poodle parent: it gives you a rough idea of adult size, but your own tape measure is the real answer.
Want every detail, including neck, back length and weighing at home? Read our complete guide to measuring your dog.
Cockapoo harness size by brand
Each brand cuts its sizes differently, so the same dog can be a different size, or a different letter, in each. Here is how a typical adult Cockapoo fits each chart, and why.
Julius-K9
IDC Powerharness
Julius-K9 lists a chest range and a weight range for every size5. Chest girth is the main guide; we use weight to choose between two sizes when the chest fits both.
- A smaller Cockapoo (chest 40 cm, 6 kg): size Mini-Mini (also fits Baby 2)
- A typical Cockapoo (chest 52.5 cm, 9 kg): size Mini (also fits Mini-Mini)
- A larger Cockapoo (chest 65 cm, 12 kg): size Mini (also fits 0, 1)
Overlaps in the Cockapoo range: 40–45 cm: sizes Baby 2 and Mini-Mini both fit; 49–53 cm: sizes Mini-Mini and Mini both fit; 58–65 cm: sizes Mini and 0 both fit; 63–65 cm: sizes 0 and 1 both fit.
Sizes overlap by design; chest girth is the main guide, weight is secondary.
| Size | Chest | Weight |
|---|---|---|
| Baby 1 | 29–36 cm | 0.8–3 kg |
| Baby 2 | 33–45 cm | 2–5 kg |
| Mini-Mini | 40–53 cm | 4–7 kg |
| Mini | 49–67 cm | 7–15 kg |
| 0 | 58–76 cm | 14–25 kg |
| 1 | 63–85 cm | 23–30 kg |
| 2 | 71–96 cm | 28–40 kg |
| 3 | 82–115 cm | 40–70 kg |
| 4 | 96–138 cm | 70–90 kg |
Highlighted rows are the sizes typical adult Cockapoos need.
Check price on AmazonRuffwear
Front Range Harness
Ruffwear sizes the Front Range Harness by chest girth only6, so your tape measure is all you need.
- A smaller Cockapoo (chest 40 cm): size XXS
- A typical Cockapoo (chest 52.5 cm): size XS
- A larger Cockapoo (chest 65 cm): size S
Sized by chest girth only.
| Size | Chest |
|---|---|
| XXS | 33–43 cm |
| XS | 43–56 cm |
| S | 56–69 cm |
| M | 69–81 cm |
| L/XL | 81–107 cm |
Highlighted rows are the sizes typical adult Cockapoos need.
Check price on AmazonBailey & Coco
Trail & Glow Harness
Bailey & Coco sizes the Trail & Glow Harness by chest girth only7, so your tape measure is all you need.
- A smaller Cockapoo (chest 40 cm): size XS (also fits XXS, S, M)
- A typical Cockapoo (chest 52.5 cm): size S (also fits M)
- A larger Cockapoo (chest 65 cm): size L (also fits S, M)
Overlaps in the Cockapoo range: 40–41 cm: sizes XXS and XS both fit; 40–50 cm: sizes XS and S both fit; 40–65 cm: sizes S and M both fit; 55–65 cm: sizes M and L both fit.
Very adjustable, so neighbouring sizes overlap a lot. Sized by chest girth only.
| Size | Chest |
|---|---|
| XXS | 22–41 cm |
| XS | 26–50 cm |
| S | 35–66 cm |
| M | 40–71 cm |
| L | 55–83 cm |
| XL | 71–99 cm |
Highlighted rows are the sizes typical adult Cockapoos need.
Check price on AmazonPuppies and growing dogs: when to re-measure
Because Cockapoos range so much in adult size, their growth varies too. Smaller dogs reach their adult weight sooner than larger ones8, so a toy-sized Cockapoo may settle into its adult harness size much earlier than one from a Standard Poodle.
Coat changes as a puppy grows, and grooming changes the fit, so keep checking the harness after grooms and growth spurts.
The largest study of puppy growth so far, based on records from over 6 million young dogs, grouped dogs by adult weight: under 6.5 kg, 6.5–9, 9–15, 15–30 and 30–40 kg8. An adult Cockapoo at 6–12 kg falls in the under 6.5 kg and 6.5–9 kg and 9–15 kg groups.
Size a puppy on its chest measurement today, not on the size you expect it to reach4. A harness bought to "grow into" is loose now, and a loose harness slips, rubs and is easier to back out of.
While your puppy is growing fast, we suggest measuring its chest every two weeks, then monthly until it stops changing. A quick check in between: if you can no longer slide two fingers under the straps, measure again.
Most harnesses adjust over a good part of their range, so a growing puppy may stay in one size for a while. When your puppy's chest reaches the top of its size's range, move up.
If your Cockapoo is between two sizes
Brand charts often overlap, so a chest measurement can fall inside two sizes. Here is where that happens for a typical adult Cockapoo:
- Julius-K9: 40–45 cm: sizes Baby 2 and Mini-Mini both fit; 49–53 cm: sizes Mini-Mini and Mini both fit; 58–65 cm: sizes Mini and 0 both fit; 63–65 cm: sizes 0 and 1 both fit.
- Ruffwear: no overlapping sizes in this range.
- Bailey & Coco: 40–41 cm: sizes XXS and XS both fit; 40–50 cm: sizes XS and S both fit; 40–65 cm: sizes S and M both fit; 55–65 cm: sizes M and L both fit.
How to choose:
- Our size finder picks the size where your dog's measurement sits nearer the middle of the range, so the harness can be adjusted either way.
- Ruffwear says that if your dog is right on the border between two sizes and fully grown, choose the larger size6. For a growing puppy that is truly between sizes, Ruffwear also suggests the larger one4.
- For Julius-K9, check the weight ranges too: if your dog's weight only fits one of the two sizes, go with that one5.
- Deep-chested dogs with a narrow waist can slip a loose harness, so if the larger size would only just fit on its tightest setting, the smaller one is usually safer.
Fit checks when the harness arrives
Two-finger rule
You should be able to slide two fingers flat under every strap, and no more6. Tighter than that can rub; looser can slip.
Strap behind the front legs
The strap around the body should sit a little way behind the front legs, not pressed up into the "armpit", where it will rub as your dog walks.
Nothing on the throat
Every strap at the front should sit on the breastbone or low on the chest, not across the throat.
Free shoulders
Watch your dog walk and trot. Its stride should look the same as without the harness. A small study found harnesses can shorten how far the shoulder reaches forward9, so if the stride looks shorter, adjust the fit or try another style.
Check for rubbing
After the first few walks, look behind the front legs, under the chest and around the neck for redness or broken hairs. If you find any, loosen or reposition the harness. If the skin is sore, stop using it and ask your vet.
Escape test
With the harness on, gently pull the lead forwards, then backwards and upwards. The harness shouldn't slide over the shoulders or ribs. If it does, tighten it, or choose a design with an extra strap behind the ribcage.
Re-check after a week
Webbing and buckles can settle in the first few walks. Check the two-finger fit again after a week.
Harness styles that suit a Cockapoo
Flat, smooth-strapped Y-front harness
Less surface in contact with the coat means less matting, and it keeps pressure off the throat.
Step-in harness
Easy to put on a wriggly puppy without pulling anything over its head.
Plenty of adjustment
A harness with adjusters on both the neck and chest straps copes better with coat changes between grooms.
Be careful with
- Full vest harnesses on a curly coat: they press a lot of coat flat, which can lead to mats underneath.
- Buying by "mini" or "maxi" labels. They aren't fixed sizes, so measure.
Common mistakes
- Measuring over the coat, not through it.
- Not adjusting after a groom, so the harness is suddenly loose enough to slip.
- Leaving the harness on at home, where it can mat the coat.
- Measuring the neck instead of the chest. Harness sizes are set by chest girth.
- Assuming a size letter means the same thing in every brand. A Medium in one brand can be a Large in another, so check each chart in centimetres.
- Buying a size up "to grow into" for a puppy.
Collar and ID tag: the UK rule
In the UK, a harness doesn't replace a collar. A dog in a public place must wear a collar with the owner's name and address on it, or on a tag or plate attached to it10. Many owners clip the lead to the harness and use the collar for ID.
Cockapoo harness questions
What size harness does a Cockapoo need?
An adult Cockapoo usually has a chest of 40–65 cm and weighs 6–12 kg1. That usually means Julius-K9 IDC Powerharness: sizes Mini-Mini or Mini; Ruffwear Front Range Harness: sizes XXS to S; Bailey & Coco Trail & Glow Harness: sizes XS to L. Measure your dog's chest to get the exact size.
How do I measure my Cockapoo for a harness?
Stand your dog square, then wrap a soft tape around the widest part of the chest just behind the front legs4. Keep it flat and snug and read it in centimetres. Measure twice. See our full guide to measuring your dog.
What size harness for a Cockapoo puppy?
Size a puppy on its chest measurement today, not its expected adult size4. Measure every couple of weeks while it grows fast and move up a size when its chest reaches the top of the current size.
What if my Cockapoo is between two harness sizes?
What size harness does a mini Cockapoo need?
"Mini" isn't a fixed size, because it depends on the Poodle parent and on the individual dog2. Measure the chest and use the size finder to get an exact size in each brand.
Why does my Cockapoo's harness keep getting loose?
Usually because of grooming: the coat under the straps is thinner after a clip. Re-adjust to the two-finger fit after each groom.
How do I stop my Cockapoo's harness matting its coat?
Choose smooth, flat straps, take the harness off after walks, and brush the areas under the straps regularly.