Future updates will support round pans. For now, convert round pans to their area manually (πr²).

Does this change bake time?

Not directly. Thinner layers often bake faster—start checking early and use visual doneness cues.

Can I go from a sheet pan to a cake pan?

This handles area only. Very different pan depths or materials may need additional adjustments beyond scaling ingredients.

Do I scale oven temperature?

Usually no. Keep the same temperature and adjust time based on thickness and doneness checks.

How do I handle a loaf pan?

Loaf pans aren’t rectangular in the same way; approximate their base area or stick to a pan with similar geometry.

cooking calculator

Pan Size Converter

Scale recipes when switching between rectangular pan sizes (area-based).

Results

Original area (sq in): 81.00
New area (sq in): 117.00
Scale multiplier: 1.44
Percent change: 14444.44%

How to use this calculator

Enter the original pan’s length and width.
Enter the new pan’s length and width.
See the scale factor and percent change to adjust your recipe.

Inputs explained

Original pan length/width: Inside dimensions of the pan your recipe was written for.
New pan length/width: Inside dimensions of the pan you want to use.

How it works

We compute the area of each pan (length × width) and divide new area by original area to get the scaling multiplier.

Formula

Scale factor = (new length × new width) ÷ (old length × old width)

When to use it

Scaling brownie or cake batters between square and rectangular pans.
Adapting casserole or bar recipes to the dishes you own.
Adjusting ingredient quantities to maintain thickness when swapping pan sizes.

Tips & cautions

Area scaling changes thickness; baking time may need slight adjustment—start checking earlier for thinner layers.
Round pans aren’t supported yet; you can convert round pans to area (πr²) and plug the numbers in manually.
Line or grease pans as usual; this calculator only handles area, not heat transfer differences between materials.
Rectangular pans only; round/loaf/tube pans require manual area conversion.
Baking time is not calculated—thinner batters often bake faster.
Assumes similar batter depth preferences between pans.

Worked examples

9×9 to 9×13

Original area = 81 sq in
New area = 117 sq in
Scale factor ≈ 1.44

8×8 to 9×9

Scale factor ≈ 1.27 — increase ingredients by 27%

Deep dive

This pan size converter compares pan areas to give a scale factor and percent change when swapping baking dishes. Enter original and new pan dimensions to know how much to multiply your recipe by.

Use it to keep brownies, bars, and casseroles the right thickness when moving between 8×8, 9×9, and 9×13 pans. Adjust bake time separately if the batter ends up thinner or thicker.

FAQs

Round pans?: Future updates will support round pans. For now, convert round pans to their area manually (πr²).
Does this change bake time?: Not directly. Thinner layers often bake faster—start checking early and use visual doneness cues.
Can I go from a sheet pan to a cake pan?: This handles area only. Very different pan depths or materials may need additional adjustments beyond scaling ingredients.
Do I scale oven temperature?: Usually no. Keep the same temperature and adjust time based on thickness and doneness checks.
How do I handle a loaf pan?: Loaf pans aren’t rectangular in the same way; approximate their base area or stick to a pan with similar geometry.

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