How to Choose a Tent: The 6 Numbers on the Tag

Between a $90 tent and a $500 tent there isn't $410 of fabric. There are six numbers on the spec tag, and once you can read them, the price differences stop being mysterious. This is what each one actually tells you.

1. Hydrostatic head (HH): how much rain it takes

Hydrostatic head measures how much water pressure a fabric resists before it leaks, in millimetres. The scale is straightforward:

• Under 1,000 mm — water-resistant, not waterproof. Fine for a drizzle, not for a night of rain.
• 1,500 mm — the minimum most manufacturers recommend for a real three-season tent.
• 3,000 mm — solid protection, including sustained rain.
• 5,000 mm+ — expedition and storm conditions.

Two details matter more than the headline number. First, floors should be rated higher than walls, because ground moisture is constant while rain is intermittent. Second, a 3,000 mm fly still leaks if the seams aren't taped — water gets in through the needle holes from stitching, not through the fabric. Look for "fully taped seams", not "critical seams taped".

2. Floor area: the person count lies

A "4-person tent" does not mean four adults sleep well in it. The industry figure is roughly 20 inches (50–60 cm) of width per sleeper — a narrow sleeping bag, no gear, no elbows.

Do the arithmetic yourself:

• Sleeping area: about 20 in wide × 80 in long per person
• Gear: allow 16–24 in of depth in the middle if there's more than one of you
• Peak height: 4 ft or more if you want to sit up and change clothes; 6 ft if you want to stand

A tent nominal for four is comfortable for two with gear and workable for three. That isn't a marketing trick — it's the standard.

3. Poles: aluminium, not fibreglass

For a tent you intend to keep, aluminium is the better buy. Fibreglass is normal on entry-level models — acceptable for car camping, not for anything carried.

4. Freestanding, or not

A freestanding tent holds its shape with poles alone. It pitches on hard ground, on rock, on sand, and you can pick it up and move it after it's up. Almost every car-camping and three-season tent is freestanding, and it is the right default for a first tent.

Non-freestanding shelters need stakes or trekking poles to stand, and they save 30–50% of the weight in exchange for a steeper learning curve. That trade makes sense for experienced backpackers, not for a first purchase.

5. Ventilation: why you wake up wet

Moisture inside a tent usually doesn't come from outside. It comes from you — roughly 0.5 to 1 litre of water per person per night through breathing and skin. Without somewhere for it to go, it condenses on the inside of the fly and drips.

What to look for:

• Two vents — one high, one low, to create movement
• A double wall — mesh inner lets vapour out, the fly keeps rain off
• Mesh on doors and vents, so ventilation doesn't mean insects

A single-wall tent is lighter, but it gives condensation nowhere to go.

6. Packed size: what fits in the trunk

Packed size is the least-read number on the tag and the most regretted. For backpacking, under 20 in (50 cm) so it lies across the pack. For car camping it matters less — but a 20 cm difference is real when the trunk is already full.

One tip worth knowing: many tents ship with separate stuff sacks for poles and body, which lets you pitch the fly first and keep the inner dry when it's raining.

The short version

If you take three numbers into the store, take these: HH of 3,000 mm, 20 inches of width per sleeper, aluminium poles. The rest follows. And store the tent loosely and dry — a tent packed damp in a basement for a year comes out smelling of mildew and leaking at the seams.