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Cake Pan Calculator / 9 inch round to 8 inch square
King Arthur & Joy of Baking Geometry Standard

9 Inch Round to 8 Inch Square Pan — Exact 1:1 Match

Area-based volume scaling for round, square, loaf, Bundt, and 9x13 sheet pans.

Scaling Ratio
1.00x (Virtually Identical Area)
Both a 9-inch round (63.6 sq in) and an 8-inch square (64 sq in) have the same volume. 100% interchangeable!
Never fill pans more than 2/3 full
Interactive Pan Area Comparator

Pan Geometry & Oven Science Guide

A 9-inch round pan has an area of 63.62 sq inches ($pi imes 4.5^2$). An 8x8-inch square pan has an area of 64.0 sq inches ($8 imes 8$). They are a virtually 100% PERFECT 1:1 MATCH.

You can swap an 8x8-inch square pan and a 9-inch round pan with zero recipe scaling and identical baking times. It is one of the most convenient pan substitutions in baking.

Standard Cake Pan Surface Area & Volume Guide

Surface area dictates batter depth, while volume dictates maximum safe capacity.

Pan Name & Dimensions Surface Area Batter Capacity Ratio vs 8" Round
6-inch Round (2" deep) 28 sq in 4 cups 0.56x
8-inch Round (2" deep) 50 sq in 6 cups 1.00x (baseline)
9-inch Round (2" deep) 64 sq in 8 cups 1.27x
10-inch Round (2" deep) 79 sq in 10-11 cups 1.57x
8x8-inch Square (2" deep) 64 sq in 8 cups 1.27x (matches 9" round)
9x9-inch Square (2" deep) 81 sq in 10 cups 1.61x
9x13-inch Rectangle 117 sq in 14-15 cups 2.33x (matches two 9" rounds)
8.5x4.5-inch Loaf Pan 38 sq in 6 cups 0.76x
9x5-inch Loaf Pan 45 sq in 8 cups 0.90x
10-inch Bundt Pan 78 sq in 12 cups 1.55x
9-inch Springform Pan 64 sq in 10 cups (3" deep) 1.27x

Pan Substitution Rules & Baking Physics

Exact 1:1 Match

63.6 sq in vs 64.0 sq in — completely interchangeable with zero ingredient adjustments.

Same Bake Time

Bake at the recipe's exact specified temperature and time.

Corner Alert

In the square pan, check the four corners 2 minutes early to ensure they do not overbrown.

Frequently Asked Questions

Can I use an 8-inch square pan instead of a 9-inch round pan? +
Yes! They have identical surface areas (64 sq in vs 63.6 sq in). Use the recipe as written with no changes.
Does baking time change between 9" round and 8" square? +
No, because the surface area and batter depth are identical, bake times remain the same.
Can brownies in an 8x8 pan be baked in a 9-inch round? +
Yes! Brownies will bake to the exact same fudge-like density in a 9-inch round pan.

Related Pan Conversions

8 inch to 9 inch cake pan →9 inch to 8 inch cake pan →9x13 pan to round pan →9x13 pan to 8 inch round →9x13 pan to 9 inch round →8 inch round to 8 inch square →9 inch round to 9 inch square →8 inch round to 9 inch square →8x8 square to 9x13 pan →9x9 square to 9x13 pan →8 inch round to loaf pan →9 inch round to loaf pan →10 inch bundt to 9x13 pan →10 inch bundt to round pan →6 inch to 8 inch cake pan →8 inch to 10 inch cake pan →
Baking & Kitchen Cluster Cross-Links

Verified ingredient weight conversions and pan geometry calculators across our baking suite:

Butter Sticks Converter 113.4g per stick Yeast Packet Converter 7g = 2 1/4 tsp Cake Pan Size Converter Area & volume 250g Butter to Sticks 2.2 sticks (block) 7g Yeast to Teaspoons 2 1/4 tsp 8" to 9" Cake Pan 1.27x factor 9x13 Pan to Round Two 9" rounds 1 Stick Butter in Grams 1/2 cup / 8 tbsp Instant vs Active Dry 1.25x ratio 9" Round to 8" Square Exact 1:1 match
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