Everyone I've talked to, vets, trainers, and long-time dog owners, all agree that harnesses are way safer than collars. A harness gives you way more control without risking injury. But figuring out what size harness your dog needs is a mess. Some brands say to size by weight, but that's only half the story. A 40-pound Bulldog and a 40-pound Greyhound are built nothing alike. One's thick and stocky, the other's sleek and narrow. It's the same weight and a totally different shape.
Take French Bulldogs, for example. You need something that won't choke them or squeeze their barrel-shaped chest. A soft, step-in harness that spreads out the pressure works way better for them than anything tight around the throat. When I started getting serious about harness sizing, I was knee-deep in Karma Dog Training classes with my crazy adolescent Labrador. I had tried about four harnesses before I found one that fit her right.
Around the same time, I talked to two vets and a canine behaviorist for their take. They all said the same thing: Every dog needs a harness, no matter if they're tiny, giant, lazy, or wild. At the end of the day, it's not about the brand or the style. It's about getting the right fit. That's what makes the difference between a dog that walks happy and safe and one that's pulling, choking, or wiggling free. That's what made me sit down and put this guide together. I figured if I could help even one dog owner get the perfect harness fit for his furry friend, I would save him the headache I went through with my Labrador.
How to Get the Perfect Harness Fit
A dog harness is built to fit around your dog's chest and the widest part of their neck. The whole point is to spread out pressure so it doesn't all hit one spot. Instead of pulling on the throat as a collar does, a good harness uses a few contact points to balance the load across the chest and shoulders. When I talked to Dr. Amy Attas from City Pets in New York, she explained it perfectly.
She said harnesses aren't just for the big leash-pullers. They're the perfect gear for flat-faced breeds like Bulldogs, Frenchies, and Pugs. She also recommends them for senior dogs, such as dogs with neck pain, breathing problems, and heart issues. Basically, if your dog's got anything going on with their airway or spine, a harness is the way to go. But here's the part no one likes to admit: a badly fitted harness causes just as much damage as a collar. Maybe even more because people think they're being safer and stop paying attention.
If a harness rubs wrong, squeezes too tight, or shifts around while your dog moves, you're looking at sore spots, restricted breathing, and joint problems over time. So, how do you know if your dog's harness fits like it should? I'm going to walk you through some signs to watch for. Then, I'll walk you through how to take measurements for a perfect harness fit.
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The dog escapes from the harness: If the dog manages to wiggle free from the harness, it's either the harness is too loose, or the wrong shape for your dog breed.
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Signs of discomfort: Dogs are pretty clear when they're uncomfortable. You just have to watch. If your dog keeps scratching at the harness, walks stiff, keeps stopping, or seems weird after the walk, something's wrong.
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Pressure points around the shoulders and neck: A harness should spread pressure across your dog's chest and back, never the throat. If you hear coughing or gagging when your dog pulls, that harness is working more like a bad collar.
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Harness shifts and slides during walks: A good harness stays put. It shouldn't twist sideways or ride up toward the neck while your dog moves. If it does, that's a sign the fit isn't correct.
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The harness requires constant adjustment: If you find yourself messing with the straps every five minutes, it's not the right harness. You shouldn't have to fight with it. A properly fitted harness goes on quickly and stays put the whole time. Now, when I buy gear, I look for harnesses with strong quick-release buckles and easy adjustment points, such as Hunter Tactical Harnesses. These harnesses don't need constant adjustments.
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Rubbing and bald patches around the chest and shoulders: If you see hair thinning, redness and rough patches where the harness sits, it means the harness is too tight or rubbing the wrong places. But note that some harnesses have stiff seams and edges that can wear down your dog's skin. I recommend you go for the Alpine Dog Terrain Harnesses. They are all lined with neoprene, so this won't be an issue.
Now, if you notice any of the above signs, it doesn't mean the harness is bad. It's something to do with the fitting. I once told a friend this, and she was quick to trash my idea, saying the harness size chart matches her dog. But the truth is that size charts are just a starting point. Breeds vary a lot, even when they weigh the same. Always pull out the measuring tape and take measurements. Here's a step-by-step guide.
Understand How the Harness Fits
A properly designed harness should look like an H on the dog's back and a Y on the front of their chest. The front of the harness should sit right on the sternum, the solid bone in the middle of your dog's chest. That's the spot meant to take pressure if your dog lunges or pulls. If the harness sits too high and rides up on the throat, it acts more like a collar, which defeats the whole point. If it's too low, it interferes with your dog's front legs while walking.
The top part, which looks like an H from above, should sit squarely over the ribcage. Not up near the neck, not down by the belly. You want to feel a solid rib under the strap, not a soft stomach. For dogs with narrow waists and deep chests, like Greyhounds, Dobermans, and German Shorthaired Pointers, standard harnesses don't always fit right.
Consider a safety harness with an extra belly strap. However, avoid anything with straps that press into the soft belly area. If you can't find one that avoids the belly completely, make sure the leash attaches to a ring over the ribcage. That way, you're not pulling on anything fragile.
Prepare the Dog for Measurements
Before you ever bring out the measuring tape, make sure the dog is calm. You don’t want the dog to think you’re paying tug-of-war with the tape. I usually take five minutes to set the mood by giving her the treats. Sit on the floor with her, not above her. That part matters. If you stand over her with a measuring tape, she will get stiff and uneasy, especially if she’s a guard dog like the Rottweiler or German Shepherd. But when you’re on her level, it’s just another chill moment together.
A vet tech friend once told me that dogs don’t just need to be still; they just need to feel safe. So, always make sure she knows it isn’t the vet, there are no needles, and nothing bad’s about to happen. Another tip is to take the dog for a short walk first. A tired dog is easier to work with than one full of zoomies. I suggest you take measurements after breakfast but before her second walk. She’s awake, alert, but not so full of beans that she can’t stand still.
Also, make sure she hasn’t just eaten a huge meal. A full stomach can make her body shape a little different around the chest and belly. As for location, indoors always wins. Outdoors, there’s way too much going on, like birds, squirrels, and neighbor dogs barking. I have also learned never to jump into measuring. Spend a few minutes just hanging out with her, letting her sniff the tape, and giving her scratches behind the ears. That way, the tape measure will feel like a toy, not a tool.
Make Sure the Dog Stands Naturally
Measure when the dog is standing naturally. Not sitting, not lying down, not stretching into weird yoga poses. If you measure when your dog is slouched or twisted, you’ll end up buying the wrong fit.
I recommend carpeted rooms, as she’s less likely to shift or slide around while you’re trying to wrap the tape around her. Plus, if you’re kneeling for a while, your knees won’t hurt. Sometimes, I even ask a friend to help. One is to feed treats, and the other is to handle the tape. Two hands just aren’t enough when your dog decides to throw in a dramatic flop halfway through.
Take Measurements
I suggest you take four measurements: chest girth, neck size, belly circumference, and back length. Each one tells part of the story, and skipping even one means the harness might rub, slide, or simply fail to work. But before I give you a breakdown of those measurements, there’s something I’d like to make clear.
You’ve probably heard the two-finger rule when it comes to fitting a harness or collar. Most people say you should be able to slide two fingers between the strap and your dog’s body. That’s not bad advice, but it’s not perfect either. When I asked Dr. Attas about it, she gave me a better version.
She said you should have to squeeze those two fingers in. Not jam them in, but there should be a little resistance. It shouldn’t be loose enough that your fingers slide in with no effort. That usually means the harness is too loose. If your furry friend has a fluffy coat, squeezing the fingers should get even trickier. So, keep that in mind when taking the following measurements.
Chest Girth
Chest girth is the widest area of the rib cage, which is the area right behind the front legs. This is the most important measurement. Every harness brand lists chest girth as its primary sizing factor. If this number is off, everything else will feel wrong.
To measure it, wrap the tape around the broadest part of her chest, then add an inch for comfort. Also, account for deep-chested dogs like Greyhounds and Pointers. They need more coverage under the chest, not just around it. So don’t just measure the circle; look at the shape also.
Neck Size
This one tripped me up the first time. A harness doesn’t sit where the collar does. Most harnesses wrap around the lower part of the neck, closer to the shoulders. That’s the base of the neck, not the top.
Measure around that lower neck area, right above the shoulders. If the neck opening is too small, your dog’s going to hate slipping it on. If it’s too loose, the whole harness shifts around like a broken seat belt. However, this won’t be an issue if you’re using a step-in harness like the Hunter Beach Tactical Harness.
Belly Circumference
This one doesn’t get mentioned as much, but it matters. Some harnesses have a third strap or panel that runs along the belly, especially the no-pull styles. If the belly strap is too tight, it’ll dig in. If it’s too loose, the whole harness rotates and gaps. To measure the belly, wrap the tape just in front of the back legs.
Note that this measurement is important for thicker-bodied dogs like Bulldogs and barrel-chested mutts. Also, dogs gain and lose weight just like us. If your dog’s belly measurement changes a lot, like after winter, adjust the harness and size up. That means you’ll need to check your dog’s belly measurements every few months.
Back Length
Some people skip this one, but they shouldn’t. Back length matters if you’re buying a harness with a long body panel or if you have dogs like Dachshunds and Corgis. For these dogs, if the harness is too short, it bunches up in the middle. If it’s too long, it rides up over the hips and restricts movement.
The rear strap also digs into the dog’s tailbone and makes her walk like she is stepping on eggshells. To take the back length measurements, start at the base of the neck, not the top of the head, and go to where the tail begins.
Choosing a Fitting Harness
Once you’ve got the dog’s measurements, now comes the shopping. And honestly, picking a harness is more complicated than it should be. Every brand has a different idea of what medium means. One company’s medium barely fits a 30-pound dog, and another’s could wrap around a Husky with room to spare.
So, I learned early on to ignore the size label and go straight to the numbers. The first thing I do is pull up the manufacturer’s sizing chart. Good brands like Alpine Dog give you a size range for chest girth, neck size, back length, and neck to behind-the-foreleg measurements for their different categories of small, medium, large, and extra large.
Another tip: only buy harnesses with at least four points of adjustment around the shoulders, chest, belly, and neck. That way, you have a wider fit window. Interestingly, the Alpine Dog harnesses come with four points of adjustment. That means when you take measurements and then buy a harness from Alpine Dog, you’re sure it’ll fit.
Final Thoughts
A fitting harness shouldn’t be something your dog tolerates. It should be something she forgot she’s even wearing. If you’re seeing rub marks, constant adjustments, and escape attempts, something isn’t right with the harness fit. I suggest you avoid the guesswork. Take a tape and measure. Then, buy a harness that matches your dog’s size and shape. I recommend Alpine Dog harnesses because they have four points of adjustability, and the company gives a clear sizing guide.