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Tent Size Calculator

A tent rated for six sleeps six only if nobody brings anything and nobody sits up. Tell it who is going, what they sleep on and how much comes inside, and it works out the floor area you actually need, then translates that into the rating you should be shopping for.

Who is sleeping in it
What they sleep on
What comes inside

Per person. This is the allowance most size guides forget, and it is usually what makes a tent feel too small.

What the weather will do

Adds room to move, sit and keep wet kit off the beds.

How the number is worked out

Four steps, all visible above, none of them hidden.

  1. Sleeping footprint. Standard sizes: a regular sleeping mat is about 13.4 sq ft, a single air bed or cot about 20.3, a child mat about 8.3. A double air bed is counted as 16.7 per person because two people on one bed use less floor than two singles.
  2. Gear allowance. Nothing, 4 sq ft a head for bags and boots, or 9 if everything comes in. This is the step most tent size advice leaves out entirely.
  3. Living space. A multiplier for how much time you will spend inside, because a tent you only sleep in and a tent you sit out a storm in are different purchases.
  4. Translate to a rating. Divide by 15.45 sq ft, which is the median floor area per rated sleeper across the 38 tents in our floor area table. That is the honest exchange rate between what makers print on the box and what you get.

What this cannot know

Floor area is not the only thing that decides whether a tent works. Shape matters: 100 sq ft in a straight wall cabin is far more usable than 100 sq ft in a dome that slopes away at the edges. Peak height decides whether you can stand to get dressed. Doors and vestibules decide whether wet boots ever come inside at all. Treat the number as the floor you should not go below, not the whole answer.

Sleeping sizes here are standard mat and mattress dimensions, not measurements we took. The per sleeper median is ours, from the tents we have reviewed. More on how we work: how we test. Think a figure is off? Tell us.