To calculate facade stone, multiply the width of each elevation by its height, subtract windows and doors, then add a waste allowance.
Cornices, window surrounds and carved pieces are priced by the linear metre or by count, and are kept separate from the flat area.
A common waste allowance is 5 to 10 percent for ordinary facades, and more for heavily detailed ones.
Order the full quantity from one lot so no colour shift shows, and keep a few square metres for future repairs.
