First things first
It’s important to remember when you’re setting out to buy a tent that there aren’t standardised measurements for tent manufacturing. What one maker will classify as a two-person tent, another will call a one-person tent, and so on. Starting with size is a good way to begin. The best tents for families involve a lot of space, both for your own bodies and for the clothing and supplies you want to keep inside the space of the tent.
Packs, sleeping bags and supplies take up room. A good general rule of thumb is to size up from manufacturing recommendations: if a tent says it’s made for four people, consider it about right for two. A family of four or more will require a tent marketed for at least six. If you're camping with children or have teenagers who really want privacy, consider getting a tent with rooms or separated areas, so that retreat is possible. It’s also a good idea to buy a tent where everybody can sleep inside their sleeping bags without touching the walls, to avoid getting cold or dripped on in the night. Even with excellent ventilation, tents can still develop condensation on interior walls - and the opposite is also true; staying cool in a tent can involve choosing one made from a particular material as well as following best practise.