Running out of stove fuel halfway through a trip is no fun. Carrying way more than you need isn't ideal either.

So how much camping stove fuel should you bring?

There are a few things that will determine how much fuel you'll use on a trip. Here's how to make a reasonable estimate.

What affects camping stove fuel use?

Your stove's published fuel consumption is a good starting point, but real-world conditions make a difference.

What you're cooking.  Simply boiling water for dehydrated meals uses much less fuel than simmering rice or cooking a meal for 20 minutes.

Water temperature. Very cold water takes longer to boil. Melting snow requires considerably more fuel.

Altitude. Water boils at a lower temperature at higher elevations. While this doesn't necessarily add much to boil times, food can take longer to cook.

Wind and weather. Wind can dramatically reduce stove efficiency. A properly used windscreen and heat reflector can make a big difference.

How to calculate how much stove fuel you need

Start by estimating how much water you'll need to boil over the entire trip, including water for meals, coffee, tea and other hot drinks.

As a simple rule of thumb, you can estimate 1 litre of boiled water per person, per meal. If you're cooking rather than just boiling water, this is still a useful starting point, although meals requiring long simmer times will use more fuel.

Next, look up the specifications for your stove. You're looking for information such as:

• How long does it take to boil 1 litre of water?
• How much water can it boil with a given amount of fuel?
• How long will a fuel canister or bottle run?

You'll usually find this information on the stove packaging or manufacturer's website.

If you want a more accurate estimate, plan out your meals and calculate the actual amount of water you'll need to heat each time.

Example: fuel for two people on a three-day trip

Let's say two people are heading out for three days with an MSR WindPro II canister stove. They'll be making two hot meals and drinks each day.

Using our 1 litre per person, per meal guideline:

• 2 people × 2 litres = 4 litres per day
• 4 litres × 3 days = 12 litres total

According to MSR's published specifications, the WindPro II can boil approximately 1.8 litres of water per ounce of fuel.

• 12 L ÷ 1.8 L = 6.7 oz of fuel

That means an 8 oz (227 g) canister should provide enough fuel for the trip, while a 4 oz (110 g) canister likely wouldn't.

You can also calculate this using boil time. If your stove takes approximately 3.6 minutes to boil a litre of water:

• 3.6 minutes × 12 L = about 43 minutes of stove time

Compare that with the manufacturer's estimated burn time for your fuel canister or bottle.

Keep in mind that stove specifications are generally based on controlled conditions. Wind, cold temperatures and your cooking habits can all increase fuel consumption, so we prefer to err on the side of bringing a little too much.

Camping stove fuel guidelines

For a quick estimate, here are some rough guidelines based on MSR liquid fuel bottles and canister sizes. These assume two people, two hot meals per day and approximately 1 litre of boiled water per person per meal in good conditions.

**Treat these as estimates rather than guarantees. If it's cold or windy, you're melting snow, or you like meals that require plenty of simmering, bring extra.

How to make your camping stove fuel last longer

A few small habits can noticeably reduce the amount of fuel you use:

• Keep a lid on your pot whenever possible.
  
• Use a windscreen and heat reflector where appropriate. Never use a windscreen in a way that encloses or overheats a fuel canister. Follow your stove manufacturer's instructions.
  
• You don't always need to run your stove at full blast. Turning it down slightly can reduce heat escaping around the sides of the pot.
  
• Have your water, food and cooking gear ready before lighting the stove so you aren't wasting fuel while you get organized.
  

Not sure whether that half-used fuel canister has enough left for another trip?

One simple trick is to float it.

Fill a pot with water and place the canister in it upright. Tilt it slightly to release any air trapped underneath, then let it float. The more fuel remaining in the canister, the deeper it will sit in the water.

MSR IsoPro canisters have a handy float gauge printed on the side to help you estimate how much fuel remains.

One last tip

Fuel calculations will always be estimates. Your stove, meals, weather and cooking habits all make a difference.

When in doubt, give yourself a little margin. A few extra grams of fuel are generally preferable to discovering on the last morning that there's no coffee.