Harness for medium dogs — what to check before you buy
'Medium' is not a fixed, standard size across harness brands, so the label alone tells you less than you would expect — a chest measurement, taken with a soft tape around the widest part of your dog's ribcage, is what actually matters when choosing a harness sized for a medium dog. Beyond size, the main practical choice is between a back-clip and a front-clip design, which change how a harness behaves on a walk.
What 'medium' means on a size chart
Every brand sets its own size ranges, so a medium in one harness can overlap with a small or large in another, particularly for breeds that sit right on the boundary between weight categories. Chest girth, not weight alone, is the measurement that decides fit, since two dogs of the same weight can have very different builds.
Measure around the widest part of your dog's ribcage, just behind the front legs, with the tape snug but not tight, and check that figure against the specific harness's own size chart rather than assuming 'medium' on the label matches your dog by name alone.
Front-clip or back-clip
A back-clip harness, with the lead attachment between the shoulders, is the simplest and most comfortable option for a dog who already walks reasonably well on a lead, and it does not discourage pulling in the way a front-clip design can.
A front-clip harness, with the attachment on the chest, gently turns a pulling dog back towards you when they lean into the lead, which many owners find helps with training a dog out of pulling without any extra equipment. Some harnesses offer both a front and a back attachment point on the same design, giving the choice without needing two separate harnesses.
Getting the fit right
A properly fitted harness should sit snugly without rubbing, with enough room to fit two fingers flat under any strap, and should not restrict how freely your dog's front legs move at the shoulder. A harness that is too loose can let a dog back out of it, particularly one who is nervous or startled, while one that is too tight can chafe on longer walks.
Check the fit again after a week of regular wear, since straps can loosen slightly with use and a growing or changing dog's measurements are worth rechecking periodically rather than assumed to stay the same as when you first measured.
What we stock
Everything below is in stock with us, priced with delivery worked out, and packed and posted by hand in the UK.
Red Dingo Classic Dog H-Harness
Red Dingo Classic Dog H-Harness in ten colours, sizes XS to Large. Hard-wearing, comfortable and finished with solid hardware — and, like all Red Dingo gear, covered by their 5-year guarantee.
From£19.99
Red Dingo Design Dog H-Harness
Red Dingo Design Dog H-Harness in 25 designs, sizes XS to Large. Hard-wearing, comfortable and finished with solid hardware — and, like all Red Dingo gear, covered by their 5-year guarantee.
From£22.49
Halti Anatomy Harness
A three-clip harness with neoprene padding that keeps a pulling dog's weight off its neck
From£37.99
Red Dingo Classic No-Pull Dog Harness
Red Dingo Classic No-Pull Dog Harness in two colours, sizes Small to Large. Hard-wearing, comfortable and finished with solid hardware — and, like all Red Dingo gear, covered by their 5-year guarantee.
From£13.99
Company of Animals Carsafe Crash Tested Harness
A car harness crash tested to 32kg, that doubles as a walking harness
From£29.99
Ancol Padded Harness
A padded dog harness with a reflective band, in a range of sizes and colours
From£13.79
Red Dingo Mesh Dog Harness
Red Dingo Mesh Dog Harness in six designs, sizes XX-Small to XX-Large. Hard-wearing, comfortable and finished with solid hardware — and, like all Red Dingo gear, covered by their 5-year guarantee.
From£25.99
Halti Front Control Harness Black & Red
A front-clip harness that steers pulling from a dog's chest instead of its neck
£18.99
Halti Comfy Harness
A fleece-lined harness with an adjustable chest strap, no leg-lifting needed to put on
From£15.99
Ancol Viva Travel Harness
A car and walking harness with two D-rings, in three colours and four sizes
From£24.29
Adjustable Nylon Tactical Dog Harness for Medium and Large Breeds
A rugged tactical-style harness with a padded control handle, MOLLE webbing panels and quick-release buckles. Built for medium and large breeds, the adjustable no-pull design gives secure control on training walks and adventures.
From£12.99
Halti Walking Harness
A five-point adjustable harness with front and back lead rings and a control handle
From£16.29
Common questions
- How do I know if my dog is a medium for harness sizing?
- Measure around the widest part of your dog's ribcage with a soft tape and check that figure against the specific harness's own size chart, since 'medium' varies between brands. Weight alone is a less reliable guide than chest measurement, particularly for stockier or leaner builds.
- Is a front-clip harness better than a back-clip one?
- Neither is universally better; a front-clip design can help discourage pulling by turning a dog gently back towards you, while a back-clip is simpler and comfortable for a dog who already walks well. Some harnesses offer both attachment points, which covers either situation.
- How tight should a dog harness be?
- You should be able to fit two fingers flat under any strap without it being loose enough to slip over your dog's head or shoulders. Check the fit again after a week of wear, since straps can loosen slightly with use.
- Can a harness stop my dog pulling on the lead?
- A front-clip harness can help reduce pulling by redirecting a dog gently as they lean into the lead, but it works alongside training rather than replacing it. A harness changes the mechanics of a pull; it does not teach a dog not to pull on its own.
Related
Written by Matt Garnett, who runs Giddy Pets and is a lifelong pet owner — not a vet. This is general information, not veterinary advice, and it cannot replace an examination by the vet who knows your animal. How we write these guides.