Food & Cooking
Pan Size Conversion
Swap pans without wrecking a recipe — get the ingredient multiplier and bake-time adjustment between any two pan sizes.
Pan Size Conversion
Inputs
Results
Multiply ingredients by
× 1.83
Adjust bake time by
Approx — start checking earlier/later than the recipe says.
× 1.35
8x8 square
64.0 sq in
9x13 rectangle
117.0 sq in
How to use this
Pan swaps are an area problem, not a shape problem. A 9×13 rectangle has roughly twice the area of an 8×8 square, so the same recipe in the bigger pan is half as deep and bakes faster.
The bake-time adjustment is approximate — it scales with the square root of area because thinner batter conducts heat faster. Always start checking a few minutes early.
Formula
ingredient multiplier = target_area ÷ original_area
bake-time multiplier ≈ √(target_area ÷ original_area)
Round pan area = π × (diameter / 2)². Rectangular = length × width.
Related calculators
Recipe Scaler
Scale any recipe up or down — halve it, double it, or fit a specific serving count with the original yield intact.
Oven Temperature Converter
Convert between Fahrenheit, Celsius, and UK Gas Marks — with a "best for" hint for every temperature.
Kitchen Unit Converter
Convert between grams, ounces, cups, and tablespoons — with ingredient density for accurate volume-to-weight swaps.
Formula
multiplier = target_area ÷ original_area; bake_time ≈ √multiplier