Quick answer: To measure your dog for a harness, take three measurements: girth (widest part of the ribcage), neck circumference, and chest length (base of neck to end of ribcage). Measure with a soft tape over the fur, not too tight. Check the manufacturer’s size chart and choose the larger size if between sizes.
Last Updated: 27 May 2026
Website: pethubonline.com
Business: Pet Hub Online
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A poorly fitted harness is worse than no harness at all — too loose and your dog can wriggle free, too tight and it restricts movement and causes chafing. Taking accurate measurements before purchasing ensures you get the right size first time.
What You Need
- A flexible measuring tape (fabric or tailor’s tape works best)
- A helper to keep your dog standing still (optional but useful)
- A notepad to record measurements
Step 1: Measure the Chest Girth
This is the most important measurement. Wrap the measuring tape around the widest part of your dog’s ribcage, just behind the front legs. The tape should be snug but not tight — you should be able to fit two fingers between the tape and your dog’s body. Note this measurement in centimetres or inches.
Step 2: Measure the Neck
Measure around the base of your dog’s neck, where a collar would normally sit. This measurement helps determine the correct neck opening for step-in or overhead harness styles. Again, allow a two-finger gap between the tape and the skin.
Step 3: Measure the Length (Optional)
Some harness brands also require a back length measurement. Measure from the base of the neck (where the collar sits) to the base of the tail along the spine. This helps determine the correct harness length for vest-style designs.
Step 4: Weigh Your Dog
Most harness sizing charts include weight ranges alongside measurements. Knowing your dog’s current weight helps you cross-reference between the chart’s measurement and weight recommendations, especially when measurements fall between sizes.
Sizing Tips
- Between sizes? Generally choose the larger size and adjust the straps down
- Growing puppy? Look for harnesses with wide adjustment ranges
- Deep-chested breeds (Greyhounds, Whippets) often need a different size than their weight suggests — prioritise the chest measurement
- Barrel-chested breeds (Bulldogs, Pugs) may need sizes up from their weight range
- Fluffy coats — Measure with the coat as it normally is; do not compress the fur
Checking the Fit
Once the harness arrives, check these points before heading out:
- Two-finger gap everywhere between harness and body
- Straps sit behind the front legs, not in the armpit crease
- The chest plate sits centrally on the breastbone
- Your dog can move freely — sit, lie down, and walk without restriction
- No visible rubbing points or pressure marks after a short indoor wearing period
Frequently Asked Questions
How often should I re-measure my dog?
Re-measure every 3-6 months for adult dogs, or monthly for growing puppies. Weight changes, seasonal coat changes, and ageing can all affect harness fit. A harness that fitted perfectly six months ago may now be too tight or too loose.
My dog is between breed size categories. Which should I choose?
Always go by your actual measurements rather than breed guidelines. Breed size categories are averages, and individual dogs vary significantly. Your tape measure is more accurate than any breed chart.
This article is part of our Best Dog Harness guide. Explore the full guide for more expert information on this topic.
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