How to Measure Your Dog for a Harness

By: Sondra Wolfer

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Measuring your dog is imperative for determining what size harness she needs, but it’s simple—we’ll show you how in five steps.

5 Easy Steps to Measure Your Dog

  1. Get a cloth measuring tape like a tailor uses —OR— a length of twine, a marker, and a ruler.
  2. Make sure your dog is standing with her weight distributed on all fours and her back straight; enlist a friend to help hold your gal while you measure, if necessary.
  3. Measure your dog’s girth, or the circumference of her chest: this is the single most important dimension you need for choosing the correct dog harness size. Starting at the withers—on a dog, this is the ridge right between her shoulder blades—draw the measuring tape (or string) around her chest, just behind her front legs, and back up to her withers on the other side. Pull the tape snug, but not tight. If you used twine, mark the twine where it meets at the withers, and then measure its length against the ruler.
  4. Most dogs don’t stand still: measure your dog’s girth three times. You probably won’t get precisely the same result twice, but third time’s a charm and should give you a good idea of her true girth measurement.
  5. For some dog harness styles, you may need to obtain the circumference of your dog’s lower neck, too—this is the thickest part of her neck, just above the withers but below where her collar normally sits. Heed the manufacturer’s instructions.

Dog Harness Sizing Tips

  • Don’t rely solely on your dog’s weight and try to guess her harness size based on it. Even small breeds can be surprisingly deep chested; the Basset Hound is an example. And while a husky Newfoundland and a sleek Great Dane may weigh exactly the same, they’ll probably have different chest measurements.
  • Consider weight gain or coat growth if these variables are relevant for your dog. If they are, add two inches to your dog’s girth measurement and shop accordingly—look for a harness that will comfortably adjust to your dog’s smallest and largest girth measurements.
  • Choose the larger harness size if your dog’s measurements are in between. Then adjust the harness down for a snug fit.
  • Look to the harness manufacturer for a specific dog harness fitting guide, because recommended sizes for your dog’s measurements can vary brand to brand or style to style.

How to Adjust a Dog Harness

Before putting the harness on your dog, check the straps to make sure they aren’t twisted, which can cause chafing and throw off the fit. Depending on the style, you’ll either put the harness on over your dog’s head or over her front legs before clipping the chest buckle. Once the harness is in place, slide the strap adjustments to loosen or tighten so the harness is uniformly snug, but not too tight. The harness should be secure, but not so tight it restricts your dog’s range of motion or so loose it can catch on things or slip off. For the best fit, a dog harness with multiple adjustment points is preferable.

You should be able to slip two fingers between the harness straps and your dog. If you can fit three or more, it’s too loose. If you have to struggle to get two fingers under the strap, it’s too tight. Check the tightness along all the straps of the harness, which in most cases will lie along the lower neck, around the chest behind the front legs, and along the front of the chest. Watch for signs of chafing behind your dog’s front legs and chest where the harness moves the most. If your dog’s harness is too loose or too tight, you undermine the control, safety, and physical benefits of a dog harness.

Signs of a Poorly Fitted Dog Harness:

  • Fur loss around harness straps
  • Chafing around harness straps
  • Wiggling free of the harness
  • Harness rotates to one side or the other
  • Your dog resists walks

Can You Leave a Harness on a Dog All Day?

In a word, maybe. If her harness fits well and she’s comfortable—and you’re around to keep an eye on her—she can wear it. But allowing her to sleep in it is risky. There are plenty of points where a harness can snag on something and potentially choke a dog (see ‘keep an eye on her’ above). And be advised a wet harness left on a dog for a long time can cause skin infections. If your dog has enjoyed a watery romp outdoors, take off her harness when you come inside and hang it up to dry.

Are Harnesses Better Than Collars for Dogs?

Unlike a dog collar, a dog harness actually helps the leash do its job, especially for a large dog breed or a dog with neck problems. How is a harness different from a collar in this regard? When your dog pulls forward during a walk, the harness distributes the pressure across the chest and shoulders, and not the neck.

The benefits of a dog harness over a traditional dog collar also include greater human control of a dog who tends to pull on her lead or for walks around a busy city. And because harnesses sit low on the neck, they also help dogs with ailments exacerbated by neck pressure from a classic collar—a dog harness is an excellent choice for dogs who suffer from tracheal or respiratory problems.

Front-Clip vs. Back-Clip Dog Harnesses

While there a several types of dog harnesses, most of them come in either back-clip or front-clip styles. The front-clip dog harness is ideal for chronic leash pullers. But be advised a dog who pulls exceptionally hard on the leash can sustain a chest injury wearing a front-clip harness, which can put too much pressure on her throat when she pulls: best to opt for a back-clip harness for this dog, even though you may not enjoy as much control over her. Likewise, the back-clip harness may better accommodate the natural gait of an athletic dog, because the front-clip style can inhibit movement. You know your dog: choose wisely.

Once your dog has a harness that fits correctly and comfortably, there’s really only one thing left to do—set off with her on your daily walks or runs through city streets or the countryside, with a welcome sense of added security.

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