Buttercream Quantity Calculator
Work out how much buttercream or frosting to make for a round, square or rectangular cake. Enter the cake size and the coat thickness; the page reports the frosted area, the volume of icing and its weight in cups, millilitres and grams.
The page covers the outside of one cake: the sides plus the top, not the base, the filling layers or any board. Dimensions are in centimetres and the finish coat in millimetres, corners are treated as sharp, and the crumb coat is modelled as one extra 2 mm layer over the same surface. Volume becomes weight at 1.05 g/mL, roughly 250 g per US cup, which suits a typical American buttercream; meringue-based and cream icings are lighter. Piping, borders, rosettes, levelling trims and what stays in the bowl are not included, so allow about 10% extra for a single cake. This is a decorating estimate, not food-safety guidance. Everything runs in your browser and the page makes no network requests.