Pan Size Conversion Calculator
Swapping baking pan sizes is one of the most common challenges in the kitchen. Whether you want to bake a sheet cake in a round pan, convert a loaf recipe to muffins, or simply use the pan you have on hand instead of the one the recipe calls for, this calculator tells you exactly how to scale your ingredients. It computes the volume of each pan using standard geometric formulas, calculates the ratio between them, and returns a scale factor you can apply to every ingredient in the recipe. Enter the shape and dimensions of both your original pan and your target pan. For round pans, the calculator uses the area of a circle times depth. For rectangular and square pans, it uses length times width times depth.
Original pan
Target pan
Pan volume formulas
Round pan volume = PI * (diameter / 2)^2 * depth
Rectangular pan volume = length * width * depth
Scale factor = target volume / original volume
Multiply every ingredient quantity in the original recipe by the scale factor to get the amount needed for the target pan.
Common pan volume reference
- 8-inch round (2 in deep): approximately 100 cubic inches
- 9-inch round (2 in deep): approximately 127 cubic inches
- 9x13-inch rectangle (2 in deep): approximately 234 cubic inches
- 8x8-inch square (2 in deep): approximately 128 cubic inches
- Standard loaf 9x5x3 inches: approximately 135 cubic inches
Pan size conversion: frequently asked questions
How do I convert a recipe from a 9-inch round pan to a 9x13 pan?
A 9-inch round pan holds about 64 square inches of area, while a 9x13 pan holds 117 square inches. Divide 117 by 64 to get 1.83. Multiply all ingredient quantities by 1.83 to scale the recipe up.
Does pan depth affect the conversion?
Yes. Pan volume = area x depth. If you switch to a shallower pan, you may need less batter, or you may need to use two pans. This calculator factors in depth when you specify it.
How does this affect baking time?
A larger pan with shallower batter bakes faster; a deeper pan takes longer. As a rule of thumb, check for doneness 5-10 minutes earlier when using a larger shallower pan, and add 5-10 minutes for a smaller deeper pan.
What about springform pans vs regular round pans?
Springform pans and regular round pans of the same diameter have the same base area. The conversion factor depends only on the diameter and depth, not on whether the sides are removable.
Can I use this for loaf pans?
Yes. Enter the length, width, and depth of both loaf pans. The calculator will give you the volume ratio and the ingredient scale factor.
Official sources
- USDA Agricultural Research Service: FoodData Central.
- National Institute of Standards and Technology: Weights and Measures.
Reviewed by the CalculatorHub team, edited by James Graham, 14 June 2026. See our methodology.