How long should a gas bottle last.

Weeks.

This has been discussed a few times , and from memory , I got 2 weeks out of a 4.5 kg bottle doing the same as you , but it hadn't run out. In fact , I think it went 2 X 2 week trips before refilling.

Troy,
As there are so many variables like the jet used and the pressure in the bottle plus how far the gas is turned up it is almost impossible to say. The weather temp even has an effect also altitude.
But apart from this expect about a week so my idea is to have a back up bottle and time the thing. Remember that a back up bottle is a must as they always run out when cooking an important meal. = Murphys Law.

2kg bottle, 2 burner gas stove, lasts us about 2 weeks camping.

depends how much water you are boiling!

piece of string is easier its the same length from the middle to each end
pmsl

steve

If you quietly sneak through the trapdoor under your inlaws house while they are sleeping you will find that leaving a 9 Kilogram bottle on will not be enough gas to finish them off. And you will find you will have to wiggle around in the dark on all fours through the dogs favorite bleep ting spot under the house. You will also need to shower at a friends house on the way home and borrow an ill fitting tracksuit as the stench will be to great even for you to handle. Only to find that the next morning the father in law has discovered your gasbottle and unbeknownest to him
connects it to his bbq after refilling it and every time you go there for a family gathering you have to see and hear him brag about his great mystery find. And your girlfiiend as all women do have this unnatural knowing of your adventures and she never kisses you the same again.

Take a spare 1 kilo bottle, and get some counselling.

No hang on! It's me that needs the counselling. You just get the spare bottle.

If you have access to some digital scales, just cook something at home eg a stew
weighing the bottle before and after, time how long you cooked and you can get a rough idea on how many gm/hr. Skinnydog

I have a 3kg bottle I take out ski-ing for the weekend. I use it in a similar fashion to you and usually get about 4 to 5 weekends out of it. approx 15 days use.

"How long is a piece of string" It's twice half its length !!!!!

Jason