Rocket Stove Design Calculator

Calculate combustion chamber dimensions, chimney height, pot gap, and fuel consumption for a rocket stove from target BTU output.

Target heat output

BTU/hr

Fuel stick diameter

Fuel moisture content

Insulation thickness

Tab to move between fields

Chamber cross-section side

7.5 cm

Chimney (riser) height19 cm

Feed tube length11 cm

Pot gap (channel gap)6 mm

Pot skirt height15 cm

Outer body diameter13.5 cm

Actual output19,193 BTU/hr

Fuel consumption4.09 kg/hr

How to Use This Calculator

Enter your target heat output in BTU/hr based on the cooking task.
Set fuel stick diameter, moisture content, and insulation thickness.
The calculator outputs chamber cross-section, chimney height, feed tube length, pot gap, and fuel consumption rate.
Use these dimensions as a blueprint for building the combustion chamber and riser.
Verify that actual BTU output meets your target and adjust stick diameter if needed.

How the result changes with Fuel stick diameter

Target heat output: Desired heat output. 10,000–15,000 BTU for household cooking, 20,000+ for large pots.
Fuel stick diameter: Diameter of typical fuel sticks. Rocket stoves work best with 1–4 cm diameter wood.
Fuel moisture content: Moisture content of fuel wood. Air-dried ≈ 12–20%, green wood ≈ 30–50%.
Insulation thickness: Thickness of insulation around the combustion chamber (perlite, vermiculite, or wood ash).

Chamber cross-section side: Inner side length of the square combustion chamber opening.
Chimney (riser) height: Vertical insulated chimney above the elbow for draft and combustion.
Feed tube length: Horizontal fuel feed opening length.
Pot gap (channel gap): Gap between pot bottom and stove top for optimal heat transfer (6–9 mm).
Pot skirt height: Height of metal skirt around the pot to capture exhaust heat.
Outer body diameter: Total outer diameter including insulation.
Actual output: Actual heat output from the rounded chamber dimensions.
Fuel consumption: Wood fuel consumed per hour at full output.

Identify Input Parameters
4 parameters
Target heat output = 15000, Fuel stick diameter = 2.5, Fuel moisture content = 15, Insulation thickness = 3 = 4 input(s) provided
Calculate Chamber cross-section side
Chamber cross-section side = sticksWide * stickDiamCm
7.5 = 7.5
Calculate Chimney (riser) height
Chimney (riser) height = actualSideCm * 2.5
19 = 19
Calculate Feed tube length
Feed tube length = actualSideCm * 1.5
11 = 11