How to use the dog harness size calculator
- Measure around the widest part of the chest behind the front legs.
- Optionally measure the neck.
- Press Calculate and match the number to the brand chart.
Worked example
A dog with a 70 cm chest girth and a 40 cm neck.
- Chest girth (widest part)
- 70 cm
- Neck
- 40 cm
- Use this number
- Find it on the brand's size chart
- Between two sizes?
- Choose the larger and tighten the straps
- Fit check
- Two fingers should slide under every strap
Example values are illustrative; this result is produced by the same calculator above.
How we calculate it
Sources: Manufacturer sizing guidance (general industry convention; brands differ)
Understanding your result
Harness sizes are not standard, so the best approach is to measure your dog and compare the numbers with the maker's own chart.
Measure the chest at its widest point just behind the front legs, and the neck where a collar normally sits. Enter those two numbers and note them down.
Choose the size whose range includes your dog's chest measurement and check the neck fit.
Common mistakes
- Measuring over thick fur without compressing it slightly.
- Assuming a size medium from one brand matches another brand.
- Choosing a harness that is tight because your dog may gain or lose weight.
Good to know
- You should be able to slip two fingers under a correctly fitted strap.
- If your dog is between sizes, check the brand's advice on adjustability.
- Check the fit again as your dog grows or changes weight.
Frequently asked questions
How do I measure my dog for a harness?
Use a soft tape around the widest part of the ribcage, just behind the front legs, snug but not tight.
What if my dog is between sizes?
Choose the larger size and tighten the straps.
How tight should a harness be?
You should fit two fingers under every strap.
Is weight enough to choose a harness size?
No. A broad-chested dog and a slim dog can weigh the same but need different sizes, so chest girth matters more than weight.
Do harness sizes match between brands?
No. There is no universal standard, so always check the manufacturer's size chart before you buy.
What if the harness rubs or slips?
Check the fit again with two fingers under every strap and adjust. If it still rubs or slips, try the next size or a different style.
Sources
- Manufacturer sizing guidance (general industry convention; brands differ)
Guides about this
Related calculators
Guidance only.