Work out icing quantity instantly with clear inputs, formula shown and shareable results.
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.
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
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.
Icing scales with area, not with cake weight, so a tall narrow cake needs far more buttercream than its size suggests.
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.