How many gas cartridges should you take?

A 230 g cartridge lasts four to five days for two people cooking simply: a hot drink morning and evening, one cooked dish a day. Everything else follows from that benchmark — more people, more days, longer meals — and that is what the calculation below does.

Two conditions move it more than anything else: wind, which can double a stove’s consumption without a windshield, and cold, which means heating colder water from a cartridge that vaporises less well. The answer always counts one spare, because nothing shows how much is left in the one you are using.

Choosing the stove and how long its fuel lasts are covered in how to choose a camping stove; what goes in the kitchen crate around it, in how to organise a camp kitchen.