Robyn&Reg — Sizing & Fit Guide

Getting the right fit matters, for comfort, for safety, and so your dog can enjoy their Robyn&Reg piece as much as you do.

A Few General Notes

  • Every dog is a different shape, even within the same breed, always measure your own dog rather than relying on breed averages.
  • If your dog is between two sizes on our chart, we'd recommend choosing the larger size, particularly for a growing puppy.
  • Please check the fit again after the first few wears, and periodically after that, collars and harnesses can loosen slightly as materials settle in.
  • For guidance specific to your dog's needs (including reactive, escape-prone, or anxious dogs), we'd always recommend speaking to your vet or a qualified behaviourist alongside using our size chart.

Here's how to measure your dog properly, plus what to know before choosing a collar, harness, lead, or poo bag holder.

This guide is intended as general advice. Please refer to our Product Disclaimer for information on supervision, safety, and intended use of our products.

How to Measure Your Dog

You'll need a soft tape measure (a fabric one, like a tailor's tape) or a piece of string and a ruler. Measure with your dog standing naturally, not sitting or lying down, and keep the tape snug but not tight.

For a Harness

You'll need two measurements:

  • Neck girth: around the base of the neck, where it meets the shoulders.
  • Chest girth: around the widest part of the ribcage, just behind the front legs.

A properly fitted harness shouldn't rub, pinch, or restrict shoulder movement.

  • You should be able to fit two fingers under all straps, front and back.
  • Watch for chafing behind the front legs after the first few wears — a sign the harness may need loosening or sizing up.
  • If your dog is between sizes, we'd generally recommend sizing up and adjusting the straps rather than sizing down.

Take both measurements with the tape snug, then check them against our size chart above to find the best fit.
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How to Measure Your Dog

You'll need a soft tape measure (a fabric one, like a tailor's tape) or a piece of string and a ruler. Measure with your dog standing naturally, not sitting or lying down, and keep the tape snug but not tight.

For a Collar

Measure around the middle of your dog's neck, where the collar would naturally sit, roughly where their head meets their shoulders.

  • You should be able to comfortably fit two fingers flat between the collar and your dog's neck.
  • Too loose, and a collar can slip over the head — a real risk for narrower-headed breeds (like Greyhounds or Whippets) or nervous dogs prone to backing out.
  • Too tight can cause rubbing, discomfort, or restrict breathing.

Check the fit regularly, especially with puppies or dogs whose weight fluctuates.

Add two fingers' width to allow for comfortable movement.
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How to Measure Your Dog

For a Lead

Leads don't need to be measured to your dog, but it's worth thinking about:

  • Length — shorter leads (around 1m) give more control in busy areas; longer leads (1.2–1.8m) suit calmer walks and more relaxed dogs.
  • Clip strength — make sure the lead's clip is rated for your dog's size and pulling strength.

Always clip the lead to a secure point (collar D-ring or harness back/front clip) and check the clip is fully closed before setting off.

Inspect stitching and clips regularly for wear, particularly if your dog pulls.
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