Earth Oven Sizing Calculator

Calculate dome dimensions, door size, thermal mass, heat-up time, and cooking capacity for a cob/clay pizza and bread oven.

Interior dome diameter

Dense cob wall thickness

Insulation layer thickness

Pizzas at once

Tab to move between fields

Interior dome height

60 cm

≈ 7 credit cards

Door height38 cm

Door width45 cm

Overall outer diameter128 cm

Max 30 cm pizzas6

Max bread loaves22

Thermal mass (cob layer)355 kg

Heat-up time68 min

Recommended diameter for pizza count48 cm

Floor Area (m²)0.64

Dome Surface (m²)1.27

Insul Volume M30.16

How to Use This Calculator

Enter the desired interior dome diameter in centimeters.
Set wall thickness, insulation layer thickness, and the number of pizzas to cook simultaneously.
The calculator returns dome height, door dimensions, outer diameter, maximum pizza capacity, and thermal mass.
Use the heat-up time estimate to plan your firing schedule (typically 1.5–2 hours before cooking).
Adjust diameter to trade between pizza capacity and build materials required.

How the result changes with Interior dome diameter

Interior dome diameter: Inner diameter of the oven floor. 60–75 cm for personal use, 90–120 cm for family/entertaining.
Dense cob wall thickness: Thickness of the inner dense clay/cob thermal layer. 10–15 cm is typical.
Insulation layer thickness: Outer insulation layer (sawdust-clay, perlite, or vermiculite mix). 5–10 cm recommended.
Pizzas at once: How many 30 cm (12 in) pizzas you want to bake simultaneously.

Interior dome height: Height of the dome interior from floor to apex.
Door height: Optimal door opening height (63% of dome height for proper draft).
Door width: Door opening width (50% of interior diameter).
Overall outer diameter: Total footprint diameter including walls and insulation.
Max 30 cm pizzas: Maximum number of 12-inch pizzas that fit simultaneously.
Max bread loaves: Approximate 1 kg bread loaves that fit on the oven floor.
Thermal mass (cob layer): Weight of the dense inner cob dome layer.
Heat-up time: Approximate firing time to bring the oven to pizza temperature (~350 °C).
Recommended diameter for pizza count: Interior diameter needed to fit your desired number of pizzas.

Identify Input Parameters
4 parameters
Interior dome diameter = 90, Dense cob wall thickness = 12, Insulation layer thickness = 7, Pizzas at once = 2 = 4 input(s) provided
Calculate Interior dome height
Interior dome height = interiorDiamCm * 0.67
60 = 60
Calculate Door height
Door height = domeHeightCm * 0.63
38 = 38
Calculate Door width
Door width = interiorDiamCm * 0.5
45 = 45