Skip to content
ENExplore Calculators

Icing Quantity Calculator

Work out icing quantity instantly with clear inputs, formula shown and shareable results.

About Icing Quantity Calculator

Icing is estimated from the surface to be covered: the top circle plus the side cylinder, times a grams per square centimetre rate for the chosen thickness, with filling layers costed at 80% of that rate. Icing scales with area, not with cake weight, so a tall narrow cake needs far more buttercream than its size suggests.

Formulas

Surface area

area = pi x radius^2 (top) + pi x diameter x height (side)

Icing weight

grams = outside area x rate + layer area x rate x 0.8

Worked example

With the default values below, Icing Quantity Calculator returns Icing needed of 506. Change any input above and every figure here is recalculated in your browser.

Inputs used

Cake diameterminimum 1 cm
20 cm
Cake heightminimum 1 cm
10 cm
Filled layersminimum 0
2
Coating thicknessone of Thin crumb coat (0.15 g per cm2), Medium (0.35 g per cm2), Thick decorative (0.6 g per cm2)
Medium (0.35 g per cm2)

Results

Icing needed
506 g
Surface area to cover
942.5 cm2
Icing per filled layer
88.0 g
Approximate cups of buttercream
2.24

Step by step

  1. 1Values used
  2. 2Surface area
  3. 3Icing weight
  4. 4Icing needed= 506 g
  5. 5Surface area to cover= 942.5 cm2
  6. 6Icing per filled layer= 88.0 g
  7. 7Approximate cups of buttercream= 2.24

Assumptions and limits

  • The result is derived only from the 4 inputs listed above. Anything not among them is not part of the calculation.
  • In particular, this calculator does not take inflation, tax, fees or charges or compounding frequency into account.
  • Figures are rounded for display to 2 decimal places, so totals built from several rounded parts can differ slightly from the unrounded arithmetic.

How these calculators are built and tested is described on the Methodology page. If a figure looks wrong, please report it.

Frequently Asked Questions

How is the Icing Quantity figure worked out?

area = pi x radius^2 (top) + pi x diameter x height (side). Icing is estimated from the surface to be covered: the top circle plus the side cylinder, times a grams per square centimetre rate for the chosen thickness, with filling layers costed at 80% of that rate.

Why does this matter?

Icing scales with area, not with cake weight, so a tall narrow cake needs far more buttercream than its size suggests.

What do I need to enter?

Enter cake diameter, cake height, filled layers, coating thickness. The defaults shown are a realistic worked example — swap in your own figures to get a result you can use.

Related Calculators

Icing Quantity Calculator – Calculate Icing needed