Party Cake Slice Calculator
Reviewed by Hamza Gujjar, Algorithm Architect & Software Developer
Last updated: July 27, 2026Cake Slice Calculator
Wondering how many slices your round party cake will actually yield, and whether you need to order a second one? This calculator uses a standard party-size slice width to give you a clear count.
Formula
Circumference = π × Diameter
Slices Per Cake = Circumference / 1.5 inch slice width
Example
A 10-inch diameter cake:
Circumference = π x 10 ≈ 31.4 inches → Slices = 31.4 / 1.5 ≈ 20 slices
Why Circumference, Not Area?
Round cakes are traditionally sliced radially from the center outward, like pizza wedges - so the number of slices is determined by how many 1.5-inch-wide wedges fit around the outer edge, not by the cake's total surface area. A 1.5-inch slice width is a common casual-party reference size, noticeably larger and more generous than the thin wedges typical of formal wedding cake service.