It mainly depends on whether your cake is round or square. The square cake box is to draw the largest square within the range of diameter inches, which is the size of the box. The round cake box is calculated by the diameter of the cake blank.

One inch is 2.54cm, 12 inch =12 * 2.45cm = 29.4cm.

12 inch square cake size picture display

12 inch square cake size picture 1:

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