How much batter does that tin take?

Work in batches, not cups

Every recipe scales differently, so a chart that tells you 'six cups of batter' is only useful if your recipe happens to yield in cups you have measured. The number that transfers between kitchens is volume: how many cubic centimetres of finished cake a tin holds.

Once you know the volume of your own recipe — bake it once in a tin you have measured, or simply note that a typical single-tier home recipe yields around 3,000 cm³ — every tin size becomes a straightforward fraction or multiple of it.

That is what the third column below gives you: not grams of somebody else's batter, but how many batches of a 3,000 cm³ recipe a given tin takes.

Volume and weight by tin size

For a round tin filled to a baked height of four inches. The weight columns are the weight of the baked sponge — see the caveat below.

Why flavour changes everything

A light vanilla sponge is about half air by the time it comes out of the oven — 0.5 g/cm³. A chocolate mud cake is 0.85, and a fruit cake 1.1, denser than water. The same tin, filled to the same line, produces cakes that differ in weight by more than double across that range.

This is why scaling by weight between flavours goes wrong. If you know your vanilla recipe fills an 8-inch tin and you scale the same weight of mud batter into it, you will overfill it — and mud cake, being denser and slower to bake, is exactly the batter you least want spilling over.

Scale by volume between flavours, and by weight only within a flavour.

Doubling the diameter does not double the batter

Volume goes with the square of the radius, so a 12-inch tin holds four times what a 6-inch one does, not twice. That single fact accounts for most under-baking disasters: someone steps up two tin sizes, makes one and a half times the batter, and comes up badly short.

From the table: 6 inches takes 0.62 of a batch, 12 inches takes 2.47. Four times, exactly as the geometry says.

• Going up one standard size (6→8, 8→10) needs roughly 1.7× the batter.
• Going up two sizes (6→10, 8→12) needs roughly 2.8×.
• Adding two inches of height to the same diameter needs 1.5× — height scales linearly, unlike width.