Enrichment · Arts and Creativity · Baking

A round-pan recipe
in a 9 × 13 pan,
at the right depth.

Type the pan the recipe uses and the pan you have. The converter compares their areas and tells you how much to scale the recipe so the batter bakes as the recipe intended.

Convert the panWhat you get

The pan size converter

The worked example moves a made-up birthday cake from a 9 inch round pan to a 9 × 13 inch pan. Nothing you type leaves this browser.

Loading the calculator. If nothing appears, turn on JavaScript.

What you get

Enrichment · Arts & CreativityFree

What you finish with
The factor to scale the recipe by, both pan areas, the batter depth if you do not scale, and the factor for common pans. It prints as a summary and downloads as a spreadsheet.
Who it is for
Students learning to bake, families, and culinary or family and consumer sciences classes practising area and proportion.
Format
Browser calculator for a phone, tablet or computer, by touch or keyboard. Prints a summary; downloads a spreadsheet (.csv); export and import a file.
Access
Free. No account, no sign-in and nothing to install. Everything you type stays in this browser; nothing is sent to Caveat.
Where it lives
The Arts & Creativity space in Caveat Enrichment.
Support
Questions, a correction or a request: team@caveatacademic.com.

How to use it

  1. Choose the shape and type the size of the recipe's pan.
  2. Do the same for your pan.
  3. Optionally type how deep the batter is in the recipe pan.
  4. Read the factor and scale the recipe with it.
  5. Print the summary for the kitchen.

Convert the pan

How the pans are compared

Area of a circle and of a rectangle.

The worked example: round to rectangle9 in round63.6 sq inπ × 4.5²9 × 13 in117.0 sq in9 × 13Factor×1.84117.0 ÷ 63.6Unscaled depth0.82 in1.5 ÷ 1.84The worked example: round to rectangle9 in round63.6 sq inπ × 4.5²9 × 13 in117.0 sq in9 × 13Factor×1.84117.0 ÷ 63.6Unscaled depth0.82 in1.5 ÷ 1.84
Batter spreads to fill the floor of the pan, so area, not the pan’s name, decides how much you need.

The arithmetic

A round pan's floor is π × (diameter ÷ 2)²; a rectangle's is length × width. The factor is your pan's area divided by the recipe pan's. Multiplying every ingredient by it keeps the batter the same depth, which keeps the baking similar. Unscaled, the depth changes by the inverse of the factor.

Time and temperature

Keep the oven temperature. Thinner batter bakes faster and deeper batter slower, so check early and use a toothpick, the spring of the crumb or a thermometer. Fill cake pans about half to two thirds full. Dark metal and glass pans brown faster than light metal.

Sources

  1. King Arthur Baking Company. Pan sizes: volumes, areas and substitutions (kingarthurbaking.com).
  2. Cooperative Extension (land-grant universities). Baking guides: pan sizes, substitutions and filling (state extension services).
  3. National Institute of Standards and Technology. Handbook 44, appendix C: area units (nist.gov).
  4. OpenStax. Prealgebra 2e, section 9.5: area and circumference of circles (openstax.org).

The worked example is made up. Pans vary; measure yours. Your figures stay in this browser. Support: team@caveatacademic.com.