The 8x8" square pan has a base of 64 sq in (413 cm²).
The 8x8" square pan in centimeters, and pans of about the same size
Measured across the top, the 8x8" square pan is 20.3 × 20.3 cm, with a base of 413 cm².
Pans within 10 % of its area: two 8x4" loaf pans (64 sq in) or one 9" round pan (63.6 sq in). A recipe for the 8x8" square pan fits these without scaling; if the batter ends up deeper or shallower, adjust the baking time.
Measure a pan across the top, from inside edge to inside edge, not across the bottom or the outside: that is the size recipes and labels give. Pans with sloped sides are smaller at the bottom than the size on the label.
Factors keep the batter as deep as in the 8x8" square pan. Below 1 means make less; above 1, more.
Frequently asked questions
How big is the 8x8" square pan?
Its base is 64 sq in (413 cm²).
How do I convert a recipe from the 8x8" square pan to the 9x13" pan?
Multiply the recipe by 1.83 (about 1 3/4 ×) so the batter stays as deep. The 9x13" pan is 117 sq in.
Does the baking time change?
If the batter is deeper or shallower than the recipe’s, yes: shallower bakes faster, deeper slower. Start checking early and use the recipe’s doneness test.