Round pizzas in inches—each area in in² and how many times larger pizza A is than B.
Each pizza is modeled as a circle using the typed diameter in inches. Areas are π(d÷2)² square inches (one decimal in the comparison line). The ratio line is area₁ ÷ area₂ (three decimals).
This calculator uses plain decimal numbers. If a result looks wrong, check whether you used a comma instead of a dot (or vice versa) where the field expects one.