NichesTools

Campfire Fuel Calculator

The calculator estimates the mass of wood or charcoal required to sustain a user‑defined heat output over a specified time. It multiplies the desired power in kilowatts by the burn duration to obtain total energy demand in kWh, then divides this by the fuel’s effective energy per kilogram—considering its intrinsic calorific value and combustion efficiency—adding an optional safety margin to buffer against environmental losses.

Specify how hot you want your fire to be on average, in kilowatts (kW). 1 kW equals roughly 3.4 kBTU/h.
How many continuous hours you expect the fire to burn at that output.
Choose the type of wood or charcoal you will use. Each option lists its average energy density in kWh per kilogram.
What percent of the fuel’s energy actually becomes usable heat at the fire, accounting for incomplete burning and heat loss to surroundings.
Extra % of fuel you add to be safe against wind or uneven burn. Typical values are 5‑15%.

What it is

The Campfire Fuel Calculator gives outdoor enthusiasts an exact estimate of how many kilograms of wood or charcoal they’ll need to run a fire at a chosen heat level over a set time. The tool takes into account the fuel’s calorific value, typical combustion efficiency (how much of that energy actually heats the camp), and adds a safety margin for wind or uneven burn. This precision helps campers avoid under‑fueling, which leads to cold fires, or over‑fueling, wasting both weight and cost—critical when packing limited gear.

How to use it

Enter your desired heat output in kW, how many hours you plan the fire will run, and pick the fuel type from the drop‑down. Specify the combustion efficiency (a percentage of energy that becomes usable heat) – common values are 60‑90%. Add a safety margin of about 5‑15% to account for leaks or weather. Click calculate; the result tells you exactly how many kilograms to bring.

Worked example

Step 1: Desired power of 2 kW over 4 h yields total energy demand ENERGY = 2 kW × 4 h = 8 kWh. Step 2: Wood has an average calorific value of 5 kWh per kilogram. With 80 % combustion efficiency this becomes EFFECTIVE_PER_KG = 5 kg⁻¹ × (80 / 100) = 4 kWh/kg. Step 3: Raw fuel mass before safety margin is RAW_FUEL = 8 kWh ÷ 4 kWh/kg = 2.0 kg. Step 4: Adding a 10 % safety margin: FUEL_NEEDED = 2.0 kg × (1 + 10 / 100) = 2.20 kg. Thus you should bring roughly 2.20 kg of wood for a steady 2‑kW campfire lasting four hours.

Inputs

  • Desired Heat Output: 2
  • Fire Duration: 4
  • Fuel Type (energy per kg): 5
  • Combustion Efficiency: 80
  • Safety Margin: 10

Result

  • Fuel Needed (kg): 2.2

Frequently asked questions

Why do I need to enter combustion efficiency rather than the fuel type alone?

Combustion efficiency accounts for how well the fire burns in real conditions – incomplete burning, wind loss, and heat escaping into the air all reduce the usable energy from the same amount of wood. Using a realistic percentage (often 60‑90 %) gives a more accurate fuel estimate than assuming perfect combustion.

Can I calculate for other types of wood?

Yes, you can switch between the two built‑in options or use the "Wood (average)" choice and manually adjust the energy value. If you know a specific species’ calorific value in kWh/kg, simply enter that as the fuel_energy_per_kg numeric field when customizing your calculation.

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