What size tent do you need?

By the Canvasdale team · Last checked 21 October 2026

A guide, not advice. Check your kit maker's figures before you buy or pack.

Size your tent from the beds you'll sleep on, not the number on the box. A berth rating counts how many people fit lying side by side on narrow mats, with nothing else in the bedroom. Most families use airbeds or camp beds and keep bags inside, so they need one or two more berths than there are people.

The short answer

Measure your beds, add room for bags and shoes, and look for a tent whose bedroom floor covers that. Then check the berth rating is at least one more than the number of people sleeping.

Why berth ratings run small

Makers rate tents by how many standard sleeping spaces fit in the inner tent. That's a fair way to compare one tent with another, but it isn't how families camp. A double airbed is much wider than two thin mats, children spread out, and nobody wants their bags outside in the rain.

So a "4-berth" tent usually sleeps four people comfortably only if they're on slim mats and keep their kit in the living area. Put a double airbed and two children's mats in it and the bedroom fills up fast. That's why we suggest looking at the bedroom floor first and the berth number second. Our guide to tent berth ratings goes into more detail.

How to work it out

1. List the beds. Write down each airbed, camp bed or mat and its length and width. The sizes are on the box or the maker's page.
2. Lay them side by side. Add the widths together, with a small gap between each bed and at both walls. The longest bed sets the length, plus a little at the head and foot.
3. Add room for kit. Bags, shoes and a bit of space to move. We start with an allowance on top of the bed area, and you can change it.
4. Add the dog. If your dog sleeps inside, add the size of its bed.
5. Compare with the tent. Look at the inner tent sizes the maker gives. For tents with separate bedroom pods, check each pod against the beds you'll put in it.

The tent size calculator does all of this and shows the working, in metres with feet and inches alongside, since UK listings use both.

Bedroom pods and living space

Family tents split the floor into bedroom pods and a living area. A tent can have plenty of floor in total but a pod too narrow for your double airbed, so check pod by pod. Two adults on a double usually want their own pod; two children on mats can often share one.

The living area matters most on wet days. If you expect rain, and in Britain you should, a living area big enough for everyone to sit down out of the weather makes a real difference. That's on top of the bedroom floor, not part of it.

Common mistakes

• Buying on berths alone. It's the most common reason a family tent feels cramped.
• Forgetting the airbed is bigger inflated. Use the inflated size from the box, not the size you guess from the bag.
• Not checking the pitch. A big family tent with its guy lines needs a big pitch. Check the site's pitch size before you book.
• Not pitching it at home first. You'll see how the beds fit and find any missing poles before you're on site.

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