5 Signs Your Dog's Collar or Harness Size Needs Adjusting

Quick answer

Check your dog's collar or harness fit every few weeks, especially during growth or weight changes. The general rule is two fingers should fit snugly between the collar and your dog's neck, and the harness should not shift more than an inch in any direction. If you notice any of the five signs below, adjust the fit or consider a different size.

A well-fitted collar or harness is essential for your dog's comfort and safety, but many owners overlook the signs that the fit has changed. Whether it's a new puppy growing quickly or an adult dog gaining or losing weight, the right fit isn't permanent. Here are five clear signs that it's time to adjust your dog's gear.

We'll walk you through each symptom, its likely cause, and the corrective action you should take. We'll also point out when it's better to stop adjusting and choose a different size or style.

1. Your Dog Is Scratching or Rubbing at the Collar or Harness

If your dog frequently scratches at their collar or harness, it's often a sign of irritation from a too-tight fit. The constant friction can rub against the skin, causing discomfort or even chafing. Another cause could be the material itself, but if the gear is made from soft, smooth materials, the fit is the more likely culprit.

Check the fit by trying to slide two fingers under the collar or harness. If you can't, it's too tight. Loosen it one notch at a time until the two-finger test passes. If the scratching continues after adjusting, the gear may be too small overall, and you should consider a larger size.

• Run your fingers along the edges of the gear to feel for any rough spots that could irritate the skin.

2. The Collar or Harness Slips Over Your Dog's Head

A collar that slips over your dog's head without unclipping is a classic sign it's too loose. This is a safety hazard, as your dog could easily escape during walks. The same goes for a harness that rotates or slides off the body.

Tighten the collar so that two fingers fit snugly but not tightly. For harnesses, adjust the straps so that the harness sits firmly without being restrictive. If you've tightened all the adjustment points and it still slips, the size is too big, and you need a smaller size.

• Test the fit by gently tugging the collar away from the neck; it should not slide over the head.

3. Red Marks or Hair Loss Around the Neck or Chest

Red marks, hair loss, or bald spots are serious indicators of a too-tight fit. When a collar or harness presses too hard against the skin, it can damage hair follicles and cause irritation. This is especially common with harnesses that sit too close to the armpits or collars that are too snug.

Immediately loosen the gear to relieve pressure. Give your dog a break from wearing it for a day or two to let the skin recover. If the marks persist or you notice open sores, consult your veterinarian. Once healed, re-fit the gear with the two-finger rule in mind, and if you can't achieve a comfortable fit, choose a different size or style.

• Check the fit after every walk, especially if your dog has been active and may have swollen slightly.

4. Your Dog Pulls or Stops During Walks

If your dog suddenly starts pulling, stopping, or refusing to walk, the harness or collar may be causing discomfort. A too-tight harness can restrict movement or rub against the shoulders, making walking painful. A too-loose collar can slide and choke, causing anxiety.

Observe where the gear sits on your dog's body. Adjust the straps so that the harness allows full range of motion without shifting. For collars, ensure it sits high on the neck, not too low. If the problem persists, consider a step-in harness design that distributes pressure more evenly.

• Watch your dog's gait; any hesitation or change in stride may indicate a fit issue.

5. You Can't Slide Two Fingers Under the Gear

The two-finger test is the gold standard for checking fit. If you can't slide two fingers comfortably between the collar and your dog's neck, or between the harness and your dog's body, it's too tight. This can restrict breathing and cause anxiety.

Loosen the gear until the two-finger test passes. For harnesses, check both the neck and chest straps. If the gear is already at its loosest setting and still too tight, it's time to size up. Remember that some materials, like waterproof gear, may not stretch, so a proper fit is crucial.

• Perform the two-finger test at least once a month, and after any significant weight change.

Diagnosis: Is it a fit issue or a size issue?

• Symptom: Scratching, slipping, red marks, pulling, or a failed two-finger test. Identify which symptom you're seeing to determine the likely cause.
• Likely cause: The gear is either too tight (causing irritation) or too loose (causing slipping or choking). Determine whether you need to tighten or loosen the gear.
• Corrective action: Adjust the straps or buckle to achieve a snug but comfortable fit, using the two-finger rule. Re-test the fit after adjusting; if the symptom persists, move to the next step.
• When to choose another option: If you've adjusted to the loosest or tightest setting and the symptom remains, the size is wrong. Consider a different size or a different style, such as a step-in harness for easier fit.

Waterproof gear that fits right

• Waterproof Jellies Collar - Aurora: Made from durable, waterproof materials, this collar resists dirt, odor, and moisture, and is fully washable for effortless upkeep. A waterproof collar is easy to clean, so you can quickly remove any dirt or sweat that might cause skin irritation, especially if your dog has sensitive skin.
• Waterproof Jellies Harness - Caviar: The step-in style makes getting ready a breeze, and it's thoughtfully engineered to be gentle on your dog's fur and skin—no rubbing, no irritation. A step-in harness is easier to put on correctly, reducing the chance of a poor fit that leads to rubbing or chafing.

Regularly checking your dog's collar and harness fit is a simple habit that prevents discomfort and safety risks. If you notice any of these signs, adjust the gear right away. And if you're in the market for new waterproof gear, look for designs that are easy to adjust and gentle on your dog's skin. Your dog will thank you with happier, more comfortable walks.