Cooking & Kitchen

Icing Amount Calculator

A rough guide is about 150 g of icing per 20 cm layer, scaled by pan area for other sizes.

This result is the estimated amount of icing needed to fill and coat the cake described.

Formula

Icing (g) = layers x 150 x (diameter / 20) squared.

How it works

This covers filling between layers plus a coat over the top and sides. A naked or semi-naked finish needs less; thick piped decoration needs more.

Making a little extra is safer than running short mid-cake — leftover icing keeps well in the fridge for a week.

Worked example

For example, 3 layers at 20 cm need 3 × 150 × (20 ÷ 20)² = 450 g of icing.

FAQs

Does the icing type change the amount?
Somewhat. Whipped buttercream spreads further than dense ganache, but the estimate is a fair starting point for both.

How much extra should I make?
About 10% extra covers smoothing losses and a small repair if a layer cracks.

Can I use this for cupcakes?
Roughly: one cupcake needs about 25–30 g of icing for a generous swirl.

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