The right pan.
The right amount.
Measure capacity, scale a known recipe, or work backward from the batter in your bowl. One clear calculation at a time.
A calculation you can check.
A straight-sided 20 × 20 × 5 cm pan holds 2,000 ml to the rim. At a chosen 66.7% fill, the planned batter volume is 1,334 ml. A 24 cm round pan of the same depth holds about 2,262 ml, with 1,509 ml at that fill. The recipe scaling factor is about 1.131.
Volume is a starting point.
The recipe comes with it.
Use the inside dimensions.
Round volume is π × radius² × depth. Rectangular volume is length × width × depth. In centimetres, the result is millilitres. Tapered loaf pans, tubes, Bundt pans and rounded corners need an actual water-capacity measurement instead of the straight-wall estimate.
Choose fill from the recipe.
66.7% is the editable worked-example allowance. It is not a safe limit for every batter or dough. Follow the tested recipe and pan maker’s guidance, especially for expanding yeast dough. A capacity match does not predict bake time, texture, doneness or oven clearance.
Keep the whole recipe together.
Scale each weighed ingredient by the same factor for an arithmetic starting point. A different depth, pan material or shape can require a new baking trial. The candidate pan dimensions here are illustrative straight-sided sizes, not verified measurements of products for sale.