Stucco Calculator

How to use the stucco calculator

1. The whole house, one wall or a repair. For the house, type its outside length and width, pick the stories and count the gables (the triangles of wall under the roof’s peak). For one wall, type its length and height. For a repair, pick the damage and type the patch’s area.
2. Pick the system. Three coats over lath for wood or steel framing; two coats straight onto block, brick or poured concrete; or a one-coat system over foam board and lath, with its thickness.
3. Pick the brand: QUIKRETE or Sakrete. Each counts its bags by its own coverage figures.
4. Count the windows, outside doors and garage doors. Stucco stops at each one, so their area comes off.
5. Pick the price: installed or the materials only, and whether old stucco comes off first. Type a contractor’s quote, if you have one, and the calculator says where it sits in the national range. A repair shows the price for a pro and the bags to do it yourself.
6. Pick the extra for waste. You get the bags of every coat and the water to mix them, then the lath, weep screed, corner bead, casing bead and control joints. Copy link keeps your walls. The green button opens the paint calculator’s outside mode for the same house, as stucco.

How stucco is measured

Stucco is bought by the bag, and a bag covers less the thicker you lay it. So the calculator works out the area first, then each coat on its own:

1. The walls: the distance round the house times the height from the foundation to the eaves. That height is 10 ft for the first story and 9 ft for each story above it, the same house as the siding calculator‘s. A 50 × 30 ft house is 160 ft round, so one story is 1,600 sq ft of wall.
2. The gables: half the gable’s height times its width. Over a 30 ft end under a 6/12 roof, the gable rises 7.5 ft, so it adds ½ × 7.5 × 30 = 112.5 sq ft. Two gables add 225 sq ft.
3. The openings: 15 sq ft off for a window (3 × 5 ft), 20 for a door and 63 for a garage door (9 × 7 ft). Stucco is not laid over them.
4. Each coat: the area with the waste, divided by what one bag covers at that coat’s thickness. The maker’s data sheet gives that figure: QUIKRETE’s base coat at 3/8″ says “3/8 inch (9.5 mm) 20 ft2 to 24 ft2 (1.8 m2 to 2.2 m2)”. The calculator counts at the low end of a range, so you do not run short.
5. The waste: Sakrete’s sheet says “The yield above does not allow for waste and spillage.” Mortar dropped off the hawk and left in the mixer is part of every job, so 10% extra is the default.

The three stucco systems

The 2021 International Residential Code: “Plaster shall be not less than three coats where applied over metal lath or wire lath and shall be not less than two coats where applied over masonry, concrete, pressure-preservative-treated wood or decay-resistant wood”. QUIKRETE’s guide gives each base coat a “Minimum 3/8 in thickness”, and its finish coat sheet says to “Apply a minimum 1/8″ (3.2 mm) thickness of Finish Coat Stucco”.

The 7/8″ is the code’s own figure: its plaster thickness table asks “7/8, minimum (exterior)” for cement plaster over wire lath. For masonry walls it asks “1/2, minimum”. A one-coat stucco is a proprietary system: QUIKRETE’s lightweight one-coat “can be applied as thick as 3/8 in (9.5 mm) to 7/8 in (22 mm) in a single pass when used in one-coat systems”. Follow its own evaluation report and your building department on the thickness.

How much an 80 lb bag of stucco covers

Both makers’ figures fall in step with the thickness. Half the thickness covers twice the area, so a bag covers about 7.5 to 9 sq ft at 1″ (one bag is “approximately 0.75 ft3 (21 L)” of mortar, QUIKRETE says). That is how the calculator counts a thickness a maker does not print, such as Sakrete at 3/8″. QUIKRETE’s lightweight bag: “One 50 lb (22.6 kg) bag yields the equivalent coverage area of a traditional 80 lb (36.2 kg) bag of pre-blended stucco.” The finish coat covers about three times as far as a base coat because it goes on a third as thick: “Coverage will vary with texture.”

The lath and the trim

• Lath (the systems over framing): ClarkDietrich’s diamond mesh lath comes in 27″ × 97″ sheets, 10 to a bundle. ClarkDietrich prints ASTM C1063’s laps: “Vertical laps: Overlap by 1 inch. Horizontal laps: Overlap by ½ inch.” So each sheet covers 96″ × 26½″, about 17.7 sq ft. The calculator lathes the area it plasters, with the same waste.
• Weep screed lets water out at the bottom of a framed wall. The code puts it “at or below the foundation plate line on exterior stud walls”, and “The weep screed shall be placed not less than 4 inches (102 mm) above the earth or 2 inches (51 mm) above paved areas”. It runs round the base of the walls, less the doors, in 10 ft lengths.
• Corner bead runs up every outside corner, in 10 ft lengths. A box house has 4 outside corners; an L-shaped one has 5.
• Casing bead stops the stucco “in a clear, straight line at doors, windows, and other openings”, ClarkDietrich says. The calculator counts 16 ft round each window, 17 ft for each door, 23 ft for each garage door, and the top of the walls under the eaves and up the gables’ rakes.
• Control joints divide the stucco into panels so it cracks along the joint, not across the wall. QUIKRETE: “Control joints should be installed to limit sections to no more than 144 ft2 (13 m2), or at a height/width ratio of 2.5 : 1.” On a 10 ft story that is a joint at least every 14.4 ft, plus one along each floor line. The calculator counts them on lath only.

What stucco costs a square foot

Three national cost guides price stucco installed, and they do not agree. Homewyse: “In May 2026 the estimated national average cost to Install Stucco starts at $10.69 – $17.33 per square foot”. This Old House: “Stucco siding costs between $6.36 and $9.66 per square foot for traditional stucco”. HomeGuide: “Stucco house siding costs $7 to $17 per square foot with installation”. The calculator shows the span of all three, and each guide’s own price for your walls under it.

• Materials only: HomeGuide says “Stucco prices are $5 to $9 per square foot for materials and $2 to $8 per square foot for labor.” This Old House puts traditional stucco’s materials at $6.36 a sq ft. On the house with its 10% extra (1,696 sq ft), that is about $8,500 – $15,300.
• The bags alone, at HomeGuide’s store prices of $10 – $30 for an 80 lb bag of base coat and $20 – $25 for a bag of finish coat: the house’s 170 bags of base coat and 25 of finish are about $2,200 – $5,725.
• Tearing off old stucco adds $1 – $4 a sq ft: “Removal alone costs $1 to $4 per square foot.”, HomeGuide says, and Bob Vila $1 to $3. On the house, about $11,300 – $32,900 in all.
• Siding instead: on the same walls, the siding calculator‘s HomeGuide prices give vinyl at about $6,200 – $10,800 installed and fiber cement at about $7,200 – $21,600.
• Your quote: type it in and the calculator places it in the range. $18,000 on the house is $11.67 a sq ft, in the middle of the national range.

These are national ranges in US dollars, each with the date its guide carries. A local quote is the real price.

What a stucco repair costs

HomeGuide prices a repair by the square foot in three kinds of damage, and “Most stucco repairs take 5 to 12 hours of labor ($200 to $720)”, so a small patch costs at least that. Bob Vila’s figures, which cite Angi and HomeAdvisor, are lower for the bigger jobs; the calculator shows both.

• Yourself: a 16 sq ft patch, three coats over new lath, takes 3 bags (2 of base coat, 1 of finish) and a sheet of lath. At HomeGuide’s store prices, with $40 – $60 for the vapor barrier and lath, that is about $80 – $150. A hairline crack or a small hole may need only a “25 lb. Stucco Repair & Patch Dry Bag $10 – $15”.
• Water damage: find where the water gets in before the patch. Bob Vila: “A stucco inspection will typically cost about $100 to $500 on average.” HomeGuide says $500 to $1,000.

Worked examples

• The house in the quick answer, two stories (50 × 30 ft, 19 ft to the eaves, the same openings): 2,982 sq ft to stucco. Three coats in QUIKRETE take 377 bags: 165 scratch, 165 brown and 47 finish. Add 186 sheets of lath and 34 control joints, because each story is jointed and the floor line too. Installed, about $19,000 – $51,700.
• The one-story house, installed, against a quote: about $9,800 – $26,700. A quote of $18,000 is $11.67 a sq ft, in the middle of the range; with the old stucco torn off first, the range is about $11,300 – $32,900.
• The same one-story house in a one-coat system, ½″ thick: 114 bags of QUIKRETE’s lightweight one coat (50 lb) and 25 of finish, 139 bags in all.
• One 20 × 9 ft wall with two windows, three coats in QUIKRETE: 150 sq ft to plaster, 21 bags (9 scratch, 9 brown, 3 finish), 10 sheets of lath, 2 weep screeds, 6 casing beads and 1 control joint.
• 100 sq ft of wall (a 10 × 10 ft wall with no openings), three coats: 14 bags with 10% extra (6 scratch, 6 brown, 2 finish).
• A 100 sq ft repair of large cracks: $3,000 – $5,000 for a pro at HomeGuide’s $30 – $50 a sq ft, $800 – $3,000 at Bob Vila’s $8 – $30. Yourself: the same 14 bags and 7 sheets of lath.
• A 16 sq ft patch of water damage: $960 – $1,920 for a pro, after an inspection of $100 – $1,000.

Common mistakes

• Measuring the floor, not the walls. A 1,500 sq ft one-story house has about as much wall as floor, but a two-story house with the same floor area has more wall.
• Counting every coat at the finish coat’s coverage. A base coat at 3/8″ covers about 20 sq ft a bag, while the finish at 1/8″ covers 70. Three coats over lath take nearly eight times the bags of the finish alone.
• Ordering at the high end of the maker’s range. 24 sq ft a bag is the best case; a wall that is out of plumb eats the difference.
• Leaving out the weep screed and the control joints. They are small lines on the order, and the code asks for the weep screed.
• Judging a quote by one guide. The three national guides run from $6.36 to $17.33 a sq ft installed, so a quote can look high against one and fair against another.
• Patching water damage before finding the water. The inspection comes first.

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Painting the stucco? The free paint calculator counts the gallons for the same walls, smooth or rough, and the exterior house color visualizer tries the colour on a photo of your house. Siding instead of stucco? The siding calculator takes the same house, and the free 2D planner draws its rooms to scale.

Sources, read October 17, 2026: QUIKRETE’s Stucco Selector Guide and data sheets for Scratch and Brown Base Coat Stucco, Finish Coat Stucco and Lightweight One Coat Fiberglass Reinforced Stucco; Sakrete’s data sheets for Scratch & Brown, Finish Coat and One Coat Fibered stucco; the 2021 International Residential Code (R703.7 and Table R702.1(1)); ClarkDietrich’s diamond mesh lath, lathing guide, weep screed, corner bead, casing bead and control joint sheets. The prices, read the same day: Homewyse (May 2026), This Old House (April 10, 2026), HomeGuide’s cost to stucco a house (August 9, 2023) and stucco repair cost (October 12, 2023), read through the Internet Archive, and Bob Vila (July 25, 2023). Codes and products change: your building department and your bag’s label have the last word. The codes and coverage are re-checked every year, the prices every 6 months.