What is a standard wedding cake portion size?

A standard coffee-sized wedding cake portion is 2.5cm wide by 5cm deep by the height of the cake tier (typically 10cm). This gives a slim finger-sized slice that is the traditional serving at wedding receptions, often alongside other desserts.

How many tiers do I need for my wedding cake?

As a rough guide: 1 tier serves up to 30 guests, 2 tiers up to 60, 3 tiers up to 100, and 4-5 tiers for 100+ guests. However, the actual number depends on tier diameters and whether all tiers are real cake or if some are dummy tiers for display.

Should I order extra cake beyond the guest count?

It is common to order 10-15% more portions than your guest count. Some guests may want seconds, you may want to send slices home with guests, and some portions from the very centre of each tier are not as neat. This calculator shows any surplus above your guest count.

Do round or square cakes give more portions?

Square cakes of the same dimension give more portions than round cakes because the corners add extra area. A 25cm square cake gives roughly 27% more portions than a 25cm round cake. Square cakes can be a cost-effective choice for larger guest lists.

Can I mix round and square tiers?

Absolutely. Many modern wedding cakes mix shapes for visual interest. Calculate the portions for each tier individually based on its shape and size, then add them together for your total.

BakeCalcs

Wedding Cake Portions Calculator

Calculate tiered cake sizes needed for a specific number of wedding guests using standard coffee-sized portions.

Number of Guests

Number of guests to cater for

Number of Tiers

Cake Shape

Select the shape that matches your area

Tier Height

Measure floor to ceiling or top of area

Tier Progression

How We Calculate This

This calculator uses the standard wedding cake portion size of 2.5cm x 5cm x cake height (the “coffee portion” used throughout the UK wedding industry). It calculates the number of portions from each tier based on the cake's cross-sectional area divided by the portion footprint.

The Formula

Round cake portions = Floor(pi x r² / (2.5 x 5))
Square cake portions = Floor(side² / (2.5 x 5))
Total portions = Sum of all tier portions

Standard Tier Progressions

3-tier round: 15cm, 20cm, 28cm
3-tier square: 13cm, 18cm, 25cm
Sizes scale automatically to meet your guest count

Frequently Asked Questions

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Last updated: February 2026

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