Two dogs wearing collars and harnesses, being held by leashes, with the text spring guide to get the fit.
Proper sizing of products is crucial to the safety and comfort of the dogs and cats wearing them. However, we understand it can be a confusing process for pet owners. Use these visuals as a guide for how to measure dogs properly for a collar, harness, or vest.

A Perfect Fit

How to Measure for Collars and Harnesses

A. Neck: Collars should sit up higher on the neck, so measure here when determining collar size.

B. Girth: Wrap the tape measure around the broadest part of the dog's rib cage.

For optimal fit, ensure that there is enough space for two fingers to easily slide between the collar or harness and your dog's neck or chest.

Measure first!

Dogs come in all different shapes and sizes and therefore, each has a unique fit. The best way to fit them properly is by using their measurements first and their weight range second.

Extra Small Dog


Up to 20 lbs

  • Dachshund
  • Shih Tzu
  • Yorkshire Terrier

Collar Size:


Harness Size:


Small dog


20 - 30 lbs

  • Beagle
  • French Bulldog
  • Miniature Schnauzer

Collar Size:


Harness Size:


Medium dog


30 - 50 lbs

  • Australian Shepherd
  • Bulldog
  • Shetland Sheepdog

Collar Size:


Harness Size:


Large dog


50 - 90 lbs

  • Boxer
  • German Shepherd
  • Labrador Retriever

Collar Size:


Harness Size:



90 lbs and up

  • Great Dane
  • Mastiff
  • Rottweiler

Collar Size:


Harness Size:




How to shop for your size

In the highlighted example below, 1 inch is the width of the collar and the range is 18 inches to 26 inches.

Size options

When shopping in stores, look towards the top of the hang tag for the size and range. 

Collar hang tags

Chain Collar Sizing

To properly fit a chain collar, add 4 inches to the circumference of your dog's neck. This ensures there is enough length for the collar to function properly. 

Then, use their weight to determine the proper gauge of chain.

For example, if your dog's neck is 18 inches, add 4 inches. Your dog will need a chain collar that is a minimum of 22 inches long. If your dog weighs 60 pounds, he will need a 2.5 mm gauge chain.

Where to measure a dog's neck for a chain collar
Chain sizing

Titan Prong Collar Sizing Guide

(Chrome-Plated Steel)

  1. Choose the wire gauge according to your dog's weight.
  2. Size your dog's neck and add 2 inches.
  3. If collar length needs to be adjusted, add or remove links accordingly.

Note: Collars should sit higher up on the neck, so measure here when determining collar size.

For example, if your dog's neck is 18 inches, add 2 inches. Your dog will need a prong collar that is a minimum of 20 inches long. If your dog weighs 70 pounds, the gauge should be 3mm. 

Wire Gauge According to Weight

Up to 66 lb (30 kg) 2.25 mm
Up to 77 lb (35 kg) 3 mm
Up to 88 lb (40 kg) 3.25 mm
Up to 154 lb (70 kg) 4 mm
Prong collar placement