For loaf pans, bundt pans, deep-dish pies — depth and shape change baking dynamics. Use volume-based conversion instead.

Bake time adjustment?

Same area, same depth: same bake time. Smaller area or shallower: 10-20% less time. Bigger or deeper: more time, same temp.

Standard area formula for circles. For a 9" round: π × 4.5² ≈ 63.6 in².

9×13 vs. two 9" rounds?

Two 9" rounds = 127 in²; 9×13 = 117 in². Recipes designed for 9×13 ≈ scale 92% for two-9"-round.

Cake Pan Size Converter (by Area)

Convert between round, square, rectangular pans by surface area. Same depth implied.

Result

Capacity ratio (to / from)

100.6%

Scale recipe by this factor when swapping pans.

Fromround 9
From area63.62 in²
Tosquare 8
To area64.00 in²
Ratio1.0060×
Recipe scaling100.6% of original

Step-by-step

From area = 63.62 in² (round).
To area = 64.00 in² (square).
Ratio = 64.00 / 63.62 = 1.0060 (100.6%).

How to use this calculator

Set "from" pan dimensions.
Set "to" pan dimensions.
Multiply recipe ingredients by the ratio.
Adjust bake time slightly: shallower pan = faster bake.

About this calculator

Pan substitution works on surface area when depths match. A round 9" pan has area π × 4.5² ≈ 63.6 in²; a square 8" pan is 64 in² — close enough that the swap is 1:1. But a 9×13 rectangle (117 in²) and a round 9" (63.6 in²) differ ~1.84×, so scale recipe by that factor. Always match pan depth too — same area but deeper pan needs longer baking time. For volumetric (loaf, bundt) shapes, use cake-pan-volume instead.