How thick should marzipan be on a cake?

For a Christmas or wedding cake, 5mm is the standard thickness. This gives enough depth to smooth over imperfections in the cake surface and provides a good base for fondant icing. For a simnel cake where the marzipan is exposed, 5-7mm is typical.

Do I need to apply apricot jam first?

Yes, always brush the cake with warmed, sieved apricot jam before applying marzipan. The jam acts as a glue that sticks the marzipan to the cake and prevents air bubbles. Apricot is traditional because its mild flavour does not compete with the marzipan.

How far ahead can I marzipan a cake?

Marzipan a cake at least 24 hours before applying fondant, to let the oils settle. If you are just having marzipan (no fondant), you can do it a few days ahead. The marzipan also helps seal moisture in the cake.

Should I buy marzipan or make my own?

Shop-bought marzipan (natural golden colour) works perfectly. If making your own, use a 2:1 ratio of ground almonds to icing sugar, bound with egg. Homemade has a slightly softer texture and a more pronounced almond flavour.

Should I use homemade or shop-bought marzipan?

Both work well. Homemade marzipan (ground almonds, icing sugar, egg) has a fresher almond flavour and softer texture, making it easier to roll. Shop-bought marzipan is more consistent and easier to work with for a smooth finish. For Christmas cakes, many bakers prefer shop-bought for its reliability.

BakeCalcs

Marzipan Coverage Calculator

Calculate how much marzipan you need to cover a cake based on tin size.

Cake Size (diameter or width)

Cake Height

Cake Shape

Marzipan Thickness

Standard is 5mm

How We Calculate This

This calculator works out the total surface area of your cake (top plus sides) and multiplies by the marzipan density at your chosen thickness to give the total weight needed.

The Calculation

Round cake top: Pi x radius squared
Round cake sides: Pi x diameter x height
Square cake top: width x width
Square cake sides: 4 x width x height
Marzipan weight: ~0.3g per cm² at 5mm thick

Application Tips

Knead marzipan until pliable before rolling
Dust work surface with icing sugar to prevent sticking
Roll into a circle large enough to drape over the top and down the sides
Smooth from the top outward, pressing gently to avoid air pockets

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.