Advanced options
Berth ratings assume sleeping mats touching with zero kit inside: hence the universal "+2 rule" for comfort camping. Airbeds are wider than mats (a double airbed eats 3 rated berths). Other numbers that matter: hydrostatic head 3,000mm+ for British rain, standing-height centre for family tents, and a porch/awning for wet boots and the stove that must NEVER burn inside (carbon monoxide).
What The Tent Size Calculator Works Out
- Buy a: the number of campers plus the comfort allowance for your style of camping. Berth ratings are written by optimists with tape measures: a "4-berth" means four sleeping mats touching edge to edge with kit exiled outdoors, hence the universal plus-two rule for car camping and plus-four for family base camps with standing room. Backpacking inverts the rule, packed weight pricing every berth.
- Floor space to look for: about 2.5 m2 per person, so four campers want roughly 10 m2 of sleeping and living floor.
- Check before buying: pitch time as one adult in wind, blackout bedroom fabric against the 4:45am summer dawn, and the boot test with the fridge, chairs and children the tent was bought for.
- Double airbeds, dogs and kit (advanced): a double airbed sleeps two but occupies three rated berths, each dog takes a berth, and bags stored in the bedrooms take another, so the adjusted count is the one to shop for.
- Floor space per person (advanced): override the 2.5 m2 rule, for example 3 m2 for long stays or 2 m2 for a weekend squeeze.
- Minimum hydrostatic head (advanced): the waterproof rating by season: 1,500 mm is a fair-weather festival document, 3,000 mm plus is the floor for British rain, and exposed or all-year sites want 5,000 mm. Sewn-in groundsheets stand against the draught and the slug.
- Packed weight to expect (advanced): a rough range from the adjusted berth count: about 1.2 kg per berth for backpacking tents, 2.5 kg for car-camping tents and 3.5 kg for family tents, with inflatable-beam tents about 30% heavier again. The inflatable generation converted twenty-pole hours into pump minutes, at a price and a packed weight.
- Pitch you will need (advanced): the tent's footprint plus a metre each side for guy lines, against the standard UK pitch of roughly 8 x 8 m. Doors go downwind, storm pegs serve real wind, and lines get lit or flagged against the night-time ankle.
- Style table (advanced): the berth, floor area and typical weight for your party under all three styles. Stoves and barbecues never burn inside or in the porch: carbon monoxide from a cooling disposable barbecue has its own annual toll. End-of-season clearances halve prices every September.