How to Measure Your Dog for a Harness

A harness provides more control over a dog than a collar and leash, and many people and dogs may find they prefer a properly fitted harness instead of a collar. Often a safer option for a dog who pulls at the leash, a harness takes the pressure off her throat and reduces the risk of injury. But when not fitted properly, harnesses may pose hazards: A dog may slip out of a loose harness, and straps adjusted too tightly may rub the skin and cause irritation. In order to ensure your dog’s harness is safe and effective, choose the right style and size, and adjust her harness for a proper fit.

Measuring & Sizing Your Dog for a Harness

Since dog harnesses strap under your dog’s chest, and sometimes belly, harness sizes are measured by the circumference around your dog’s chest and back, known as the girth. To measure the girth of your dog’s chest, simply wrap a soft tape measure (like one used for sewing) around the widest part of your dog’s chest and back and record the measurement. This measurement will correlate with dog harness sizing in inches or centimeters. For instance, a dog with a chest girth between 16 inches and 24 inches would need a small harness, while a dog with a girth between 20 inches and 30 inches would need a medium, in most brands. Harnesses are adjustable, and the girth sizing overlaps so that when your dog outgrows one size, they’ll certainly fit the next size up.

If you’re having trouble measuring your dog’s girth for a harness, we’ve broken it down into five easy steps:

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.

Tips for Dog Harness Sizing

• 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.
• There should be no pressure on her throat, and the harness shouldn’t pinch or bind when she walks.
• Look to the harness manufacturer for a product-specific harness fitting guide, because recommended sizes for your dog’s measurements can vary brand to brand or style to style.

How Should a Dog Harness Fit?

Your dog’s harness should fit snugly enough that it does not slide significantly back-to-front or side-to-side, and loosely enough to be able to fit two fingers under any part of the harness. A well-fitting harness will be comfortable for your dog, while a poorly fitting harness may cause pinch our rubbing points and at best be uncomfortable, or at worst cause injury.

Signs of a Poorly Fitted Dog Harness:

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

Putting a Harness on Your Dog

How you put a harness on your dog depends on the style you choose. With either a standard or step-in harness, remember to approach the dog from behind, as reaching over her head from the front may make her uncomfortable.

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 pull the harness on over your dog’s head, or over her front legs before clipping the chest buckle.

A standard harness goes over the dog’s head. To put this style harness on a dog, follow these steps:

1. Slide the harness over your dog’s head.
2. Adjust the buckles so they’re in the proper location and the harness is facing the right direction.
3. Slip your dog’s leg through the opening and fasten the buckle to create the second leg hole.
4. Adjust as necessary.

A step-in harness is convenient because it eliminates the need to pull the harness over your dog’s face or head, making it a better option for nervous or head-sensitive canines. Get your dog ready for the trek with less fuss in four easy steps:

1. Lay the harness on the ground, unclipped and open.
2. Encourage your dog to step over the harness and place each foot inside a leg hole.
3. From behind your dog, lift the buckle ends, and clip them over her back.
4. Adjust as necessary.

Adjusting a Dog Harness

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.

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. You should be able to slip two ‘stacked’ 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. Watch for signs of chafing behind your dog’s front legs and chest where the harness moves the most. If her harness is too loose or too tight, you’ll undermine the control, safety, and physical benefits of the harness.

There is no need to loosen the harness when you remove it—when you unclip the buckles, the adjusted fit will remain true. But always check for a proper fit, and adjust the harness as needed each time she wears it.

The Best Harness for Your Dog

The best dog harnesses are sturdy, comfortable, lightweight, and fit well. While many features can make using a harness easier, a proper fit is imperative. Choose your dog’s harness based on the materials, style, and features you want, and make sure you’ve adjusted it for a secure, comfortable fit before venturing out. Whatever harness style you choose, adding personalization with your contact information can help your dog find her way back to you faster if she gets lost.

Different Types of Harnesses

There’s more to choosing a harness than size alone: Consider materials, leash clip placement, and harness style. Common harness materials include:

• Nylon
• Leather
• Breathable mesh
• Reflective material

Harnesses may include a handle, which is helpful while hiking or for dogs who need a little extra help standing or climbing stairs. For added safety on the road, some harnesses double as car restraint systems. Pack-style harnesses allow your dog to carry her own supplies, lightening your load while on the trail. Most harnesses feature quick-release buckles for easy on-and-off, while others include metal buckles.

Choose a standard, sturdy, six-foot leash for use with a dog harness, or a two-point leash for added control; nylon or leather leashes are the most common options. The leash should offer a little slack, but not drag on the ground. Retractable leashes are not recommended in general, and especially not for use with a harness.

Leash clip placement varies: Some harnesses include a D-ring on the back of the harness, so the leash clips either at the base of the neck above the shoulder blades or at the bottom edge of the harness over the spine. The leash clips in the center of the chest for front-clip harnesses.

Front-Clip vs. Back-Clip Dog Harnesses

Most harnesses come in either back-clip or front-clip styles, each offering a variety of benefits.

A front-clip harness is meant to be used with a little slack in the leash, which may become a tripping hazard, especially if you often jog or hike with your dog. This style is favored for teaching dogs polite leash behavior, and it works well for pullers.

Back-clip harnesses are more versatile, offer more control, and keep the leash out of chewing range for mouthy dogs. 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.

Best Harnesses for Dogs Who Pull

Harnesses take the pressure off of a dog’s neck, so they’re often a better choice than collars for the dog who pulls—but some styles discourage pulling better than others. Because dogs instinctively tug against pressure, a back-clip-style harness can increase pulling. Front-clip harnesses are a top no-pull option for chronic leash pullers because there’s no pressure at the back for the dog to tug against.

But be advised a dog who pulls exceptionally hard on the leash can sustain a chest or throat injury wearing a front-clip harness. This style may 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.

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). Wearing a harness all day and night can be uncomfortable. Mouthy dogs may chew, and ingest, pieces of the harness—which is a choking hazard or can cause a blockage. 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, clean it as necessary, and hang it up to dry.

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.