Cake Pan Size Converter

Compare an original cake pan or pan set with a new pan size. The calculator uses total pan surface area to preserve approximately the same batter depth and provides a recipe multiplier and optional scaled batter weight.

Original pan

Shape

Pans

Diameter

New pan

Shape

Pans

Diameter

Original batter weight (optional)(g)

Use the same measurement unit for both pans.

Enter both pan sizes.

Use matching units, such as inches for both pans or centimetres for both.

How to Use the Cake Pan Size Converter

Choose the original pan shape, enter its dimensions, and select the number of pans used by the recipe.

Enter the shape, dimensions, and count for the new pan set.

Use the same measurement unit throughout. Both sets may be entered in inches or both in centimetres.

Add the original batter weight when you also want a scaled batter amount in grams.

How Cake Pan Scaling Works

The calculator finds the bottom surface area of each pan and multiplies it by the number of pans.

The new total area is divided by the original total area to create the recipe multiplier.

This approach keeps approximately the same batter depth when the pans have comparable usable depth.

Pan measurements used by the calculator

Pan measurements used by the calculator
Shape	Required dimensions	Single-pan area
Round	Diameter	π × (diameter ÷ 2)²
Square	Side length	side²
Rectangle	Width and length	width × length

Swipe horizontally to view the full table.

Common Cake Pan Conversions

A one-inch change in diameter can represent a much larger change in batter requirement because round-pan area depends on the radius squared.

For example, a 9-inch round has approximately 26.6% more surface area than an 8-inch round.

An 8-inch square and 9-inch round are very close in area and are often practical substitutes when their usable depth is similar.

Common pan-size recipe multipliers

Results assume comparable usable pan depth.

Common pan-size recipe multipliers
Original	New pan	Multiplier	Recipe change
One 8-inch round	One 9-inch round	1.266×	Increase by 26.6%
One 9-inch round	One 8-inch round	0.79×	Reduce by 21%
One 9-inch round	One 8-inch square	1.006×	Almost unchanged
One 9 × 13 rectangle	Two 9-inch rounds	1.087×	Increase by 8.7%
Two 8-inch rounds	One 9 × 13 rectangle	1.164×	Increase by 16.4%

Swipe horizontally to view the full table.

Converting Multiple Cake Pans

Pan count is included in the total area calculation.

A recipe written for one rectangular pan can therefore be compared with two or more round pans without running separate calculations.

When dividing batter between several pans, weigh each filled pan or portion the batter evenly so the layers bake at a similar rate.

Why the Calculator Does Not Ask for Pan Depth

The main goal is to preserve the recipe's existing batter depth rather than fill every pan to its rim.

Full pan height is not the same as safe batter capacity because cakes need space to rise.

When the new pan has a substantially different usable depth, measure bakeable capacity or follow manufacturer and recipe guidance instead of relying only on area.

Baking Time May Change

A thinner cake generally heats more quickly, while a deeper cake may need longer for its centre to set.

Do not multiply the baking time by the recipe multiplier.

Keep trusted recipe guidance, monitor the cake, and begin checking earlier when the batter is spread more shallowly.

Pan Material and Colour

Glass, ceramic, light metal, and dark metal transfer heat differently.

King Arthur Baking notes that glass and ceramic conduct heat more slowly than metal, while dark pans can produce stronger edge browning.

Changing both size and material introduces more uncertainty than changing size alone.

Bundt and Special-Shaped Pans

Bundt, tube, angel-food, tapered loaf, and novelty pans cannot be represented accurately by a simple round or rectangle formula.

For an irregular pan, measure its bakeable capacity with water and leave appropriate headroom for the cake to rise.

Some cakes depend on a specific pan structure and should not be transferred to another shape.

Privacy and Local Processing

The calculation runs entirely in the browser.

Pan dimensions and batter amounts are not uploaded, added to a public URL, or permanently stored.

Cake Pan Conversion Formulas

The total area of the new pan set is divided by the total area of the original pan set.

Formula variables

$d$: Round-pan diameter
$s$: Square-pan side length
$w$: Rectangular-pan width
$l$: Rectangular-pan length
$n$: Number of identical pans
$M$: Recipe multiplier

Round pan area

A = π (\frac{d}{2})^{2}

Square pan area

A = s^{2}

Rectangular pan area

A = w \times l

Total pan area

A_{t} = A \times n

Recipe multiplier

M = \frac{A _{n e w}}{A _{or i g ina l}}

Scaled batter weight

B_{n e w} = B_{or i g ina l} \times M

Can I substitute an 8-inch square pan for a 9-inch round pan?

Their surface areas are very close, so they are often practical substitutes when their usable depths are similar.

Should I enter inches or centimetres?

Either works because the calculator uses a ratio. Use the same unit for the original and new pans.

Why is pan depth not an input?

The calculator assumes you want the same batter depth. If usable depths differ substantially, compare measured bakeable capacities instead.

Can I convert one pan into multiple pans?

Yes. Enter the appropriate number of original and new pans.

Does the calculator support Bundt pans?

No. Bundt and novelty pans should be compared by measured bakeable capacity rather than simple surface dimensions.

Will baking time remain the same?

Not necessarily. Batter depth, pan material, shape, colour, and oven performance can all affect baking time.

Should I change the oven temperature?

Follow the tested recipe unless reliable pan-specific guidance states otherwise.

Are my pan sizes saved?

No. The calculation runs locally in the browser.

References

Recipe Scaling Calculator

Scale an ingredient list for more or fewer servings, including fractions, mixed numbers, decimals, and ranges.

Grams to Cups Converter

Convert grams to US cups, tablespoons, teaspoons, and millilitres using ingredient-specific baking weights.

Ice Cream Mix Calculator

Calculate milk fat, MSNF, added sugar, and total solids for a simple milk, cream, sugar, and skim-milk-powder base.

Circle Calculator

Calculate a circle's area, circumference, radius, and diameter from any one known measurement.