The 9" round pan has a base of 63.6 sq in (410 cm²).
The 9" round pan in centimeters, and pans of about the same size
Measured across the top, the 9" round pan is 22.9 cm across, with a base of 410 cm².
Pans within 10 % of its area: one 8x8" square pan (64 sq in) or two 8x4" loaf pans (64 sq in). A recipe for the 9" round 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 9" round pan. Below 1 means make less; above 1, more.
Frequently asked questions
How big is the 9" round pan?
Its base is 63.6 sq in (410 cm²).
How do I convert a recipe from the 9" round pan to the 9x13" pan?
Multiply the recipe by 1.84 (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.