What is the difference between a cake board and a drum?

A cake board (or card) is typically 2-3mm thick and sits between tiers or under lighter cakes. A cake drum is 12-15mm thick and provides a sturdy, rigid base for the bottom tier or the entire cake. Drums are essential for heavy or tiered cakes to prevent sagging or breakage during transport.

How much bigger should the drum be than the cake?

The standard recommendation is 5cm (2 inches) larger in diameter than the bottom tier on each side, giving a 2.5cm border all around. This provides enough space for decoration and prevents the cake from looking cramped. Some decorators prefer a wider 7-8cm overhang for more elaborate decorations.

What thickness drum do I need?

A 12mm drum is suitable for most cakes up to 3 tiers. For 4-5 tier cakes or very heavy cakes, use a 15mm drum or double up two 12mm drums. The drum must be rigid enough to support the total weight without flexing when lifted.

Do I need boards between each tier?

Yes, always place a thin cake card or board between each tier. This distributes the weight across the dowels below and makes it much easier to separate tiers for serving. Use a board that is the same size as or very slightly larger than the tier above it.

BakeCalcs

Cake Board & Drum Sizing Calculator

Calculate the correct board and drum sizes for tiered cakes.

Number of Tiers

Cake Type

Select the cake type for your calculation

Display Style

Choose the style that suits your project

Tier Diameters

Tier 1 (bottom)

Tier 2

Tier 3 (top)

How We Calculate This

The calculator determines the correct board and drum sizes based on your tier diameters and preferred display style. It adds an appropriate overhang around each tier for aesthetics and structural support.

The Calculation

Base drum = Bottom tier diameter + (base overhang x 2)
Intermediate boards = Tier diameter + (board overhang x 2)
Drum thickness based on total number of tiers

Frequently Asked Questions

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Last updated: March 2026

All calculations are based on standard ratios and conversions. Results may vary with specific ingredients, equipment, and conditions.