How much your dog carries should never exceed over 20% of their own body weight. For example, a 15kg dog will carry a maximum of 3kg.
But this gives you a good guide on which to buy. Most backpacks will just give you plenty of room to load up, but you want to make sure you don’t buy a huge backpack for your small terrier which risks being overloaded.
Also, think about where and when they will be using it. A little daytime trip will likely require less space than a big weekend of hiking in the Lake District.
The size you see on our review is just a guide for the company who has made the product. Fitting in a Large for one company won’t necessarily mean your dog is a Large in another, so always take note of the product measurements instead.
Most dog backpacks are usually for medium or larger breeds, so you’d struggle to get one for small or toy breeds. But they are often fully adjustable via the stomach, chest and side straps so you can make it tighter if needed.
Not really a big decision to make. You may want to match their other equipment such as collars and leads, or even your own coat.
We will say that it may be a good idea to get a backpack in a contrasting colour to your dog, however. This is especially fitting if you will be in wooded, darker areas and visibility is a must.