Stucco Coverage Calculator
Estimate the stucco for a three-coat wall — base and finish bags — from the wall area minus openings, with waste.
How it works
net area = length × height − openings · add 10% waste · base bags = area ÷ base coverage · finish bags = area ÷ finish coverage
Traditional stucco is a three-coat system — a scratch coat and a brown coat that together form the thick base, then a thin finish coat for color and texture. Base-coat mix goes on far heavier than the finish, so each bag covers much less wall, which is why the two are estimated separately. Subtract window and door openings from the wall area and add about 10% for the overspray, thickness variation and touch-ups any plaster job produces.
Worked example
A 40 × 9 ft wall is 360 sq ft with no openings; add 10% for 396 sq ft. Base coat at 25 sq ft per bag: 396 ÷ 25 ≈ 16 bags. Finish coat at 55 sq ft per bag: 396 ÷ 55 ≈ 8 bags.
Frequently asked questions
How many coats of stucco are there?
The traditional system is three coats: a scratch coat keyed into the lath, a brown coat that levels the wall, and a thin finish coat. One-coat and two-coat systems exist but the classic three-coat build is the reference here.
Why does base coat cover less than finish coat?
The scratch and brown coats are applied thick — typically 3/8 inch each — to build the wall out, while the finish coat is only about 1/8 inch. A bag of base mix therefore spreads over far fewer square feet than a bag of finish.
Do I subtract windows and doors?
Yes, subtract each opening’s area from the wall. Keep a little extra on hand, since the edges and returns around openings take more material and careful work than flat field.
Related calculators
Estimates only — add for waste and confirm against local building codes and supplier specs.