Stucco Calculator

Stucco coverage calculations determine how much material you need to cover a wall surface to the specified coat thickness. Traditional stucco is applied in three coats (scratch coat, brown coat, and finish coat); EIFS (synthetic stucco) is a two-coat system. Each coat has a different thickness and coverage rate.

Total stucco volume formula: Volume = Surface Area × Total Thickness

Bags needed formula: Bags = Volume ÷ Yield per Bag

Where:

• Surface Area — total wall area in square feet or square meters (subtract windows and doors)
• Total Thickness — sum of all coat thicknesses (traditional 3-coat: 3/8" + 3/8" + 1/8" = 7/8" = 0.073 ft)
• Yield per Bag — varies by product; typically 0.45–0.55 cubic feet per 80 lb bag
• Waste Factor — add 10–15% for cuts, corners, and mixing losses

Traditional 3-coat stucco thicknesses:

• Scratch coat (first): 3/8 inch (9.5 mm)
• Brown coat (second): 3/8 inch (9.5 mm)
• Finish coat (third): 1/8 inch (3 mm)
• Total system thickness: 7/8 inch (22 mm)

Typical coverage rates per 80 lb bag:

• Scratch/brown coat mix: ~35–40 sq ft at 3/8" thickness
• Finish coat: ~50–60 sq ft at 1/8" thickness

Mix ratio (by volume) for traditional stucco:

• Scratch coat: 1 part Portland cement : 3 parts sand
• Brown coat: 1 part Portland cement : 4 parts sand
• Finish coat: 1 part white Portland : 3 parts marble sand + pigment

Worked example: Stucco a 600 sq ft exterior wall (after subtracting windows/doors). Full 3-coat system.

• Scratch coat bags: 600 sq ft ÷ 37 sq ft/bag = 16.2 → 18 bags (with 10% waste)
• Brown coat bags: 600 sq ft ÷ 37 sq ft/bag = 18 bags
• Finish coat bags: 600 sq ft ÷ 55 sq ft/bag = 12 bags

Total: ~48 bags of stucco products. At $15–$20 per bag, material cost ≈ $720–$960 before sand, cement, and finish pigment.