How we work it out
Every calculator shows its sum, the figures it starts from and where each figure comes from. Our own planning allowances are labelled "Our assumption", and you can change any figure to match your own kit.
Where the figures come from
- Your kit: stove gas use, cartridge sizes and bed sizes come from your own box or the maker's page.
- Our assumptions: allowances such as spare gas or room for bags, labelled and editable.
- Tables: typical figures such as night-time lows (Met Office averages) and hook-up ratings. Each row names its source and the date it was checked. Until the Researcher has checked a row against its source, it says so.
Rules and safety
We explain the rules on wild camping, fires and dogs, and link to the official pages for England, Wales, Scotland and Northern Ireland. We never tell you a spot is open for wild camping: check the rules and get the landowner's permission. Gas and stove pages carry our carbon monoxide warning, word for word.
For the tent size calculator step by step, see how we size tents.
Every calculator's sum and figures
Camping checklist builder
Open the camping checklist builder
- Everyone gets their own sleeping bag, bed, chair, plates, layers, waterproof and head torch
- Cold months (October to April) add liners, hot-water bottles, hats and gloves; summer months add sun hats and repellent
- Hook-up adds the cable and a low-wattage kettle; a festival swaps the site rules for the festival's own
Tick things off as you pack, then print or copy the link. Ticks aren't saved: the link keeps your trip settings, not the ticks.
Pitch a new tent at home first. It's the best way to find a missing pole before you're on site in the rain.
This calculator has no built-in defaults: every figure comes from you or your kit's own label.
Camping gas calculator
Open the camping gas calculator
- Burner time a day = hot meals × minutes per meal + people × brews each × minutes per brew
- Gas = stove's grams per hour × burner time ÷ 60 × days
- Gas to take = gas × (1 + spare allowance)
- Cartridges: the mix of the sizes you can buy with the least gas left over, and the fewest-cartridges alternative
A stove's grams-per-hour figure is for full power. Simmering uses less; wind, cold and a big pan use more.
Gas works less well in the cold, and butane most of all: on a cold morning a cartridge can run well below its rated output. Gas sold for colder weather mixes in propane or isobutane. Check the maker's guidance for the temperatures your gas works at.
Take the spare. Running out halfway through tea is the usual way a camping trip goes wrong.
| Figure | Our default (adjustable) | Kind | Source |
|---|---|---|---|
| Hot meals a day | 2 meals | Our assumption Not yet checked against the source | Our choice: change it to suit your trip Hot meals cooked on the stove each day. Our starting point: change it to your plan. |
| Burner time per meal | 15 min | Our assumption Not yet checked against the source | Our choice: change it to suit your trip Burner-on time per hot meal for the whole group. Our assumption: one-pot meals take less, a fry-up on two rings takes more. |
| Brews per person a day | 2 brews/day | Our assumption Not yet checked against the source | Our choice: change it to suit your trip Hot drinks or washing-up water per person per day. Our assumption. |
| Burner time per brew | 4 min | Our assumption Not yet checked against the source | Our choice: change it to suit your trip Burner-on time per person's brew (part of a shared kettle). Our assumption: depends on your stove and kettle. |
| Spare for wind and cold | 25 % | Our assumption Not yet checked against the source | Our choice: change it to suit your trip Spare gas for wind, cold mornings and a stove running below its rated output. Our allowance. |
| Table | Clause | Nations | Status |
|---|---|---|---|
| Camping gas: cartridge sizes and typical burner use Researcher to cite makers' specs (Campingaz, Coleman, Primus, Calor) and Gas Safe / HSE consumer guidance on butane and propane in the cold | Net gas per cartridge or cylinder, and typical burner consumption in grams per hour | UK-wide | 0/9 values entered Not yet checked against the source |
Sleeping bag rating finder
Open the sleeping bag rating finder
- Night-time low = your forecast, or the typical low for the region and month (Met Office averages)
- Comfort rating to look for = the night-time low, or the low minus the margin if you feel the cold
- Your bag: its comfort rating against that figure (a lower number is a warmer bag)
Use the comfort rating, not the limit. The limit is lower, so a bag bought on its limit feels cold at that temperature for most people.
A bag only works as part of a system: what's under you matters as much. An airbed full of cold air can feel colder than the bag's rating suggests. Our guide to sleeping mats explains R-values.
Children's bags may be rated differently from adults' bags. Check with the maker how a child's bag was rated.
Comfort guidance only. Tents are colder than the forecast on a clear, still night in a dip, and warmer under trees.
| Figure | Our default (adjustable) | Kind | Source |
|---|---|---|---|
| How much warmer, if you feel the cold | 3 °C | Our assumption Not yet checked against the source | Our choice: change it to suit your trip How much warmer a bag to look for if you tend to sleep cold. Our assumption, not a standard figure. |
| Table | Clause | Nations | Status |
|---|---|---|---|
| Typical night-time lows by UK region and month | Met Office 1991–2020 climate averages, mean daily minimum temperature (Researcher to pick one representative station or regional series per row and cite it) | UK-wide | 0/84 values entered Not yet checked against the source |
| EN ISO 23537 sleeping-bag temperature ratings explained EN ISO 23537-1:2022 (Researcher to confirm the current edition and cite BSI or a maker's explainer) | The three temperatures on a rated bag's label, and what each means | UK-wide | 0/6 values entered Not yet checked against the source |
Tent size calculator
- Bedroom width = the widths of all the beds side by side + a gap between each and at both walls
- Bedroom length = the longest bed + a gap at the head and foot
- Floor area = bedroom width × length × (1 + kit allowance), plus the dog bed
- Berths = people + the berth margin (berth ratings count snug, mat-sized spaces)
A tent's berth rating counts how many people fit lying side by side on narrow mats, with no room for bags. Airbeds and camp beds are wider, so most families size up.
Family tents split the floor into bedroom pods. Check each pod's inner size against the beds you'll put in it, not just the total.
Living space, porches and awnings aren't counted here: this is the floor you sleep on.
| Figure | Our default (adjustable) | Kind | Source |
|---|---|---|---|
| Extra space for bags and kit | 30 % | Our assumption Not yet checked against the source | Our choice: change it to suit your trip Extra floor space for bags, shoes and a bit of room to move, on top of the beds. Our planning allowance: raise it if you keep a lot inside or want a living area in the bedroom. |
| Gap between beds and at the walls | 0.1 m | Our assumption Not yet checked against the source | Our choice: change it to suit your trip Gap between beds laid side by side, so airbeds don't push against each other or the walls. Our assumption. |
| Berths to add to the number of people | 1 berths | Our assumption Not yet checked against the source | Our choice: change it to suit your trip Berth ratings count snug sleeping spaces, usually for a mat each with no room for kit. We add this many berths to the number of people. Our rule of thumb: Researcher to check retailer and club guidance on berth ratings. |
| Table | Clause | Nations | Status |
|---|---|---|---|
| Typical bed sizes for tent floor planning Researcher to cite makers' published sizes (airbeds, camp beds, self-inflating mats) or a retailer size guide | Typical lengths and widths by bed type, used to pre-fill the tent size calculator | UK-wide | 0/7 values entered Not yet checked against the source |