Scale a recipe between baking tin sizes

How it works

Round area is πr², square area is side², and rectangular area is length × width; destination ÷ source gives the scale factor. Equal-depth tins use base area, while differing depths require both volumes, and no bake-time ratio is inferred.

• Area is the initial basis because it preserves fill depth between equal-depth tins.
• Depth becomes mandatory on both sides when volume is selected.

Worked example

											From shape: round
From dimension1 cm: 20
To shape: round
To dimension1 cm: 23
Basis: area
										

												From area cm2: 314.2
To area cm2: 415.5
From volume cm3: 0
To volume cm3: 0
Basis used: area
Scale factor: 1.32
Quantity multiplier percent: 132
Note: Multiply ingredient quantities by the scale factor. Baking time and temperature do not scale by this ratio; follow a tested recipe or check doneness independently.
											

When to use this

Round cakes move from 20 cm to 23 cm tins, brownie formulas move between square and rectangular bases, and unequal-depth tins compare geometric capacity.

Edge cases

• A rectangular tin without both length and width is rejected because its base area cannot be calculated.
• Area scaling assumes comparable fill depth; choose volume and enter both depths when capacity is the intended basis.
• Baking time and oven temperature do not change linearly with batter mass, so the geometric multiplier is not applied to minutes.