Stucco Calculator
Base- and finish-coat bags for two- or three-coat exterior walls.
How it works
Net wall area is multiplied by the allowance. Base area is then multiplied by the number of base coats and divided by base coverage per bag. Finish is divided by its own coverage, and both products are rounded up independently.
The presets use conservative QUIKRETE coverage examples for traditional hard-coat stucco. They do not design an assembly: substrate, water-resistive barrier, lath, fasteners, control joints, curing and coat schedule must follow the approved system, local code and current product data.
Related calculators
How the Stucco Calculator works
This US stucco calculator estimates a traditional hard-coat exterior wall as separate base and finish products. It supports a three-coat assembly over lath and a two-coat application over masonry, while keeping every bag coverage and price editable.
Base and finish coats are separate purchases
For the three-coat preset, scratch and brown are each 3/8 in base coats. The calculator multiplies net wall area by two before applying the base-product coverage. The 1/8 in finish coat uses its own yield and is rounded to whole finish bags separately.
The direct-masonry preset uses one 1/2 in base coat and a 1/4 in finish. It is not merely a thinner version of the lath system: the substrate and approved assembly determine which schedule applies.
The defaults use conservative bag coverage
QUIKRETE publishes approximately 20–24 ft² per 80 lb base-coat bag at 3/8 in and 15–18 ft² at 1/2 in. The calculator starts at 20 and 15 ft² so the estimate uses the conservative end of each range.
The published finish-coat example covers about 70 ft² per 80 lb bag at 1/8 in. The two-coat preset uses 35 ft² at 1/4 in by proportional depth. Texture, substrate and application technique can reduce actual yield, so all coverage fields remain editable.
Lath area is not a complete accessory takeoff
The three-coat result reports the wall area with allowance as a planning lath area. It deliberately does not invent roll count, laps, fasteners, water-resistive barrier layers, control joints or corner accessories without the selected system details.
Follow the approved assembly, ASTM C926 where applicable, local code and current product instructions for substrate preparation, lath, curing and time between coats. Material quantity alone does not establish a compliant exterior wall.
FAQ
How many stucco bags cover a 400 sq ft three-coat wall? expand_more
With ten percent allowance, the order area is 440 sq ft. Two base coats at a conservative 20 sq ft per bag require 44 base bags. A finish rate of 70 sq ft per bag requires 7 finish bags, for 51 bags total.
How is a two-coat masonry wall calculated? expand_more
The preset uses one 1/2 in base coat at 15 sq ft per bag and one 1/4 in finish at 35 sq ft per bag. For 400 sq ft plus ten percent, that is 30 base bags and 13 finish bags.
Does the calculator include metal lath and weather barrier? expand_more
It reports planning lath square footage for the three-coat preset only. Roll coverage, laps, fasteners and water-resistive barrier requirements must come from the specified wall assembly.