How to Measure and Fit a Dog Harness

A harness distributes pressure across the chest and shoulders, rather than the neck, which makes it a good choice for many dogs, particularly those who pull or have neck or breathing problems. But its benefits depend on fit. A harness that is too loose can twist or allow the dog to back out, which is dangerous near roads. A harness that is too tight can chafe, restrict shoulder movement, and affect gait.

A harness that works for one dog may not suit another of the same weight, since body shapes differ. Always measure, and try before buying if possible.

You need a soft measuring tape, and your dog standing on a flat surface. Treats help keep them still. Most brands ask for a few simple measurements.

1. Chest girth: measure around the widest part of the ribcage, just behind the front legs.
2. Neck: measure around the base of the neck, where a collar would sit.
3. Weight: weigh your dog, for brands that use weight ranges.
4. Back length: for some styles, measure from the base of the neck to the base of the tail.
5. Compare the measurements to the brand's size chart, and choose the size that fits the largest measurement.
6. If your dog is between sizes, choose the larger size and adjust.

Different styles suit different dogs and purposes. Consider what you need.

• Back-clip harness: the leash clips on top of the back. Comfortable, and good for small dogs and for dogs who do not pull.
• Front-clip harness: the leash clips at the chest. Helps reduce pulling by turning the dog toward you.
• Dual-clip harness: has both clips, for flexibility and a double-connection leash.
• Step-in harness: the dog steps into it, which can help dogs who dislike things over the head.
• Y-shaped harness: straps form a Y over the chest, leaving the shoulders free.
• Car safety harness: crash-tested and designed to connect to a seat belt.

Note: Some harness designs, such as those with a strap across the chest at the front, can restrict shoulder movement. Look for designs that leave the shoulders free, and ask a trainer or vet if you are unsure.

Put the harness on your dog, and adjust the straps. Then check the fit, with your dog standing and moving. A well-fitting harness is snug but comfortable.

• You can slide two fingers between the strap and your dog's body.
• The harness does not slip over the head or shoulders when your dog backs up.
• It sits behind the front legs, with no rubbing under the armpits.
• Your dog can walk, sit, and lie down normally.
• Straps do not twist, and the buckles lie flat.
• Fur is not bunching up, and the skin is not pinched.

Watch for the following during and after walks. If you see them, adjust the harness or try a different style.

Rubbing, redness, or hair loss around the armpits or chest. A changed gait, such as a shortened stride or a stiff front end. Backing out of the harness, or the harness riding up to the neck. Your dog trying to scratch at it, or refusing to walk. Remember that fit can change as your dog gains or loses weight, or as a puppy grows, so check regularly.

Many dogs dislike things going over their head or around their body. Introduce the harness slowly. Let your dog sniff it, give a treat, and touch it to their back. Place it on briefly, with treats, and take it off. Build up the time, and attach the leash only when your dog is relaxed.

Practice in the house first, with short sessions of play or training, then on short walks. If your dog freezes or struggles, go back a step. Patience early on leads to a dog who is happy to wear a harness for years.