About PetSizeGuide

PetSizeGuide is a sizing reference for pet supplies. It answers one narrow question and tries to answer it properly: which size should you buy for this dog?

Who runs this site

PetSizeGuide is published by the team behind hei-ai.com, a free online tools site we have been running. We build small, free, useful tools — that is the whole of our background, and we would rather state it plainly than dress it up.

We are not veterinarians. We are not dog trainers. We do not give health, nutrition, or medical advice, and we will not pretend to. If that is what you need, please talk to your vet.

What we are reasonably good at is taking messy measurements and turning them into a decision you can act on.

Why we built this

Almost every pet sizing chart on the internet says the same thing: look up your dog's weight, pick the size. That single table is the reason so many orders get sent back, because the right size for a harness is set by chest girth, the right size for a collar by neck girth, and the right size for a crate by body length and shoulder height.

So instead of one weight table, we wrote a separate calculation for each type of product, and we publish the working.

How to read our numbers

Every recommendation is a range, not a promise. Treat our answer as the size to start from, then spend the thirty seconds measuring that we show on every page. A measurement always beats an estimate. When the two disagree, trust your tape measure and ignore us.