Whether you’re hiking alpine trails, walking snowy sidewalks, or exploring your local park, your dog’s harness needs to fit properly. A bad fit isn’t just uncomfortable — it can cause rubbing, strain, and even escape risks.

Here’s exactly how to measure your dog and dial in the perfect dog harness fit.

Quick Answer: How Should a Dog Harness Fit?

A dog harness should fit snug but not tight. You should be able to slide one to two fingers between the harness and your dog’s body behind the front two legs, along the back or around the neck. It shouldn’t rub, restrict shoulder movement, or shift side to side when your dog walks.

What is the most important measurement?

• Chest size, the widest part around the dog’s chest or ribcage.

Step 1: How to Measure Your Dog for a Harness

If you have a soft measuring tape, grab that or if you have a traditional measuring tape that will work as well. 

1. Measure the Chest (Girth)

This is the one that matters most.

• Wrap the tape around the widest part of your dog’s chest
• Usually right behind the front legs
• Keep it snug but not compressing fur
• Record the measurement

If you only measure one thing — measure this, this is the most important measurement, especially for our Rocky Mountain Dog Harnesses since the neck clearance is wide enough for a dog’s head and easily adjustable.

2. Measure the Lower Neck

Measure your dog’s neck where the collar sits, keep the tape measurer snug but not tight.

3. Consider Fur & Build

If your dog:

• Has thick winter fur → allow slight extra room
• Is broad-chested (Labs, Boxers, Shepherds) → double-check girth
• Is between sizes → size up for adjustability

For active dogs, adjustability is everything.

Step 2: How to Properly Fit a Dog Harness

Once you have the right size, fitting is the difference between “good” and “perfect" fit for the dog harness and ultimate comfort and control with your dog is the goal.

1. Loosen Everything First

Start with the harness fully loosened and eyeball slight adjustments for the first fit to then decide exact adjustments. Adjust the chest straps and neck straps while it is off your dog.

2. Position It Properly On Your Dog

Unbuckle the back straps on the harness and put the harness over your dog’s head, pull the bottom part of the harness under the chest and buckle the clips around the back of the front legs. A properly fitted harness should:

• Sit below the throat
• Rest across the chest (not digging into shoulders)
• Stay behind the front legs
• Allow full shoulder extension

If it restricts stride, it’s not fitted correctly. From this first fit you will decide how much adjustment the harness needs and take it off the dog for adjustment. This is important, it is much easier to adjust the harness off the dog rather than on your dog. 

3. Adjust The Harness Off Your Dog

You will adjust the harness off your dog

• Adjust the neck size of your dog with the tri-glides along the webbing, making the harness larger or smaller based on the size of the neck
• Adjust the chest size with the tri-glides along the webbing that goes around back legs making the girth larger or smaller

Then put the harness back on your dog to check the fitting, this step may need to be repeated a couple times.

3. Tighten Using the Two-Finger Rule

You should be able to fit one to two fingers under every strap.

If the harness is too tight it may cause chafing, unneeded pressure or restrict movement.
If the harness is too loose, there will be less control while walking the dog, the harness will shift too much, sagging underneath and there would be escape risk.

Then take your dog for a short walk and recheck adjustments.

How to Tell If a Harness Is Too Tight

• Red marks under the front legs
• Hair thinning
• Shortened stride while walking
• Resistance when walking
• Excessive panting without heat

Active dogs need full range of motion — especially on trails.

How to Tell If a Harness Is Too Loose

• Slides side to side
• Chest plate drops
• Webbing straps sag around the chest or around the neck
• Your dog can back out of the harness and escape.

Loose harnesses are the number one cause of escapes.

Why Fit Matters for Hiking & Outdoor Dogs

If you're out hiking with your dog, walking around your house or travelling it's imortant for a properly fitted dog harness. It helps with:

• Mountainous terrain or outdoor trails
• Snow and icy conditions
• Steep inclines
• Using the safety handle to lift your dog
• Running with your dog

A poorly fitted harness causes:

• Shoulder strain
• Uneven pressure
• Hotspots
• Reduced control

A properly fitted, adventure-ready harness distributes weight evenly and moves with your dog.

Not sure which size to choose?

Our Summit All-Terrain Harness fits all sizes of dogs from very large breeds like German Shepards and Great Danes to small dogs like pugs and Yorkies. We have a detailed sizing guide and adjustable straps for a secure fit across all breeds. View our dog harness sizing chart.

Built for Adventure: Summit All-Terrain Dog Harness

The Summit All-Terrain Dog Harness was designed for dogs that actually get outside.

Designed to be the best all round dog harness for big dogs and  small dogs the key features are:

1. Durable material: Crafted from rip resistant polyester and a mesh padded inside for ultimate comfort. 
2. Strong straps: Designed to accommodate your dog’s movement
3. Four-points of adjustments around the chest and neck
4. Comfortable around the neck: Lots of adjustment for the perfect fit
5. Front clip leash attachment for a no-pull dog harness
6. Reflective trim: boosts your dog’s visibility in low light conditions for safety
7. Safety handle: Use the handle for controlling your dog safely
8. Back clip makes it easier than ever to clip your leash and go hands-free

These features evenly distribute the weight for ultimate comfort and the durable, trail-tested material makes this the best harness that holds up on real adventures that can withstand snow, rain and rugged terrain.