How many bags of stucco do I need?

Work out the wall area (length × height less openings), add waste, and divide by what a bag covers. For three-coat stucco a bag of base coat covers about 22 sq ft at 3/8 in, so two coats of it cover 11 sq ft of wall per bag, plus finish coat at about 70 sq ft per bag. The example house, 1,125 sq ft, with 10% waste comes to 113 bags of base coat and 18 of finish: 131 bags.

How much does an 80 lb bag of stucco cover?

Quikrete states about 20 to 24 sq ft at 3/8 in for its 80 lb base coat stucco (scratch and brown and one-coat mixes) and about 70 sq ft at 1/8 in for its finish coat. Sakrete lists 70 sq ft at 1/8 in for its scratch and brown mix. Coverage varies with texture and application, so use the number on your bag.

How thick is three-coat stucco?

About 7/8 in over lath: a scratch coat of 3/8 in, a brown coat of 3/8 in and a finish coat of 1/8 in. The total thickness is in ASTM C926; the split between coats is the usual one. A one-coat system is a single layer, typically 3/8 to 1/2 in thick.

What is the difference between three-coat and one-coat stucco?

Three-coat is a scratch coat, a brown coat and a finish coat, applied over lath, with curing time between coats. One-coat is a single pass of a fiber-reinforced mix. It is thinner and quicker, and uses fewer bags: for the example house 57 bags at 3/8 in against 113 for the base coats of three-coat, with no finish-coat bag. Check the product data sheet: one-coat systems have their own lath and substrate requirements.

Does a thicker coat use more stucco?

Yes, in proportion. At 1/2 in a bag covers about three-quarters as much as at 3/8 in, so the example house needs 75 bags of one-coat at 1/2 in against 57 at 3/8 in. This is geometry, not a maker's figure: the data sheet's own rate at your thickness wins.

How much waste should I add for stucco?

This calculator offers 10% and 20%. These are estimates of ours, not maker numbers. Stucco is lost on the ground, in the mixer and in thicker patches over out-of-plane walls, and spraying loses more than troweling. A small shed 60 ft round and 8 ft high at 20% waste needs 62 bags in all. Buying a few extra bags is cheaper than running short mid-wall, since a coat that stops partway can show as a line.

Do I subtract windows and doors?

Yes, enter each as an opening. On the example house, six 3 × 4 ft windows, two 3 × 6.7 ft doors and a 9 × 7 ft garage door take off 175.2 sq ft, leaving 949.8 and 110 bags in all instead of 131. The returns around the openings take extra material, which the waste percentage covers.

How much metal lath do I need?

Stucco goes over metal lath on wood framing and sheathing. Lath comes in sheets of 27 × 96 in (18 sq ft); the calculator counts them over the same area with the same waste, which also covers the laps: 69 sheets for the example house. Over solid masonry or concrete, lath may not be needed. Lath fasteners, weep screed, corner bead and the water-resistive barrier are separate.

Why do the manufacturers give a range, and which end should I use?

The 20 to 24 sq ft range reflects how the mix is placed and how flat the wall is. At 20 sq ft the example house needs 124 bags of base coat, at 24 sq ft 104; the calculator uses 22 (113). Use the low end for a rough wall or spray, the high end for a flat one with experienced hands.

Is this a bag of stucco or of mortar mix?

Stucco mix is a different blend from the bagged mortar or concrete mix you may also buy in 80 lb bags: it is a graded sand and cement made for plastering. See the concrete bags calculator for concrete, and the bricks calculator for mortar. Use the product the maker names for the substrate.

Stucco Calculator: 80 lb Bags of Base Coat and Finish

A house with 125 ft of wall all the way round, 9 ft high, has 1,125 sq ft to cover. With 10% waste (1,237.5 sq ft) a traditional three-coat system, about 7/8 in thick, takes 113 bags of 80 lb base coat: 57 for the scratch coat and 56 for the brown coat at 3/8 in each, at about 11 sq ft of wall per bag for the pair. Add 18 bags of finish coat at 70 sq ft a bag, 131 bags in all, and 69 sheets of 27 × 96 in metal lath. A one-coat system at 3/8 in takes 57 bags. Coverage is the maker's rate of 20 to 24 sq ft at 3/8 in; this uses 22.

Figures based on the sources listed belowUpdated 2026-10-07How we calculate

Total wall length (all the way round)

Wall height

Waste

Standard (10%)Rough wall, spray or many openings (20%)Custom

Stucco systemThree-coat is scratch, brown and finish over metal lath. A one-coat mix is a single base layer, usually 3/8 to 1/2 in thick, with no separate finish-coat bag.

Base coat: sq ft per 80 lb bag at 3/8 in (sq ft)

Quikrete states 20 to 24 sq ft at 3/8 in for its base coat, scratch and brown and one-coat mixes; 22 is the middle. Enter the figure on your bag. At 1/2 in a bag covers three-quarters as much.

Finish coat: sq ft per 80 lb bag at 1/8 in (sq ft)

Quikrete states about 70 sq ft at 1/8 in for its finish coat; texture changes it. Used only for the three-coat system.

Price per bag (optional)

Buy 113 bags

1,125 sq ft + 10% waste = 1,237.50 sq ft

Scratch coat (3/8 in): 57 bags
Brown coat (3/8 in): 56 bags
Finish coat (1/8 in): 18 bags
All bags to buy (80 lb): 131 bags
Metal lath (27 × 96 in sheets): 69 sheets (≈ 1,238 sq ft)

How this number is calculated

1,125 sq ft + 10% waste = 1,237.50 sq ft ÷ 11 sq ft per bag = 113 bags

Shopping list

Stucco base coat mix (80 lb)
Stucco finish coat (80 lb)
Self-furring metal lath
Plastering hawk and trowel
Mixing paddle for drill
Stucco weep screed
Cement mixer

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Bags by wall area and system

For a net wall area with 10% waste, in 80 lb bags at 22 sq ft per bag at 3/8 in and 70 sq ft per bag of finish. Three-coat shows base + finish = total. Worked by this calculator.
Net area	Three-coat: base + finish = bags	One-coat 3/8 in: bags	One-coat 1/2 in: bags	Lath sheets
500 sq ft	50 + 8 = 58	25	34	31
800 sq ft	80 + 13 = 93	40	54	49
1,000 sq ft	100 + 16 = 116	50	67	62
1,200 sq ft	120 + 19 = 139	60	80	74
1,500 sq ft	150 + 24 = 174	75	100	92
2,000 sq ft	200 + 32 = 232	100	134	123
2,500 sq ft	250 + 40 = 290	125	167	153
3,000 sq ft	300 + 48 = 348	150	200	184

Coverage of a bag of base coat by thickness

Sq ft one 80 lb bag covers, scaling the 22 sq ft at 3/8 in rate by 3/8 ÷ thickness (an estimate: the maker states 20 to 24 sq ft at 3/8 in), and the bags per 100 sq ft.
Thickness	Sq ft per bag	Bags per 100 sq ft
1/8 in	66	1.5
1/4 in	33	3
3/8 in	22	4.5
1/2 in	16.5	6.1
5/8 in	13.2	7.6
3/4 in	11	9.1

Methodology & assumptions

Total wall length is the distance all the way round the house and the wall height is the height of the plastered wall; the area is length × height, less each door and window you enter as an opening. Add the waste percentage (10%, or 20% for a rough, uneven wall, spray application or many openings; both are estimates, not a maker's figure) to get the area to plan for. Coverage per bag comes from the maker: Quikrete states that an 80 lb bag of its base coat stucco (scratch and brown, pump grade and one-coat mixes) covers about 20 to 24 sq ft at 3/8 in, and that a bag of finish coat covers about 70 sq ft at 1/8 in. This calculator starts from 22 sq ft, the middle of the base-coat range, and both figures are inputs, so enter the rate printed on your bag. Coverage goes down in proportion to thickness: at 1/2 in a bag covers 3/8 ÷ 1/2 = 0.75 as much, 16.5 sq ft. That scaling is geometry, not a maker's figure. Three-coat stucco is two base layers at 3/8 in (scratch, then brown) and a 1/8 in finish, 7/8 in in all, so a bag of base coat covers 11 sq ft of wall for the pair; bags of base coat = area ÷ 11, rounded up, split between scratch and brown; finish bags = area ÷ 70, rounded up. A one-coat system is one layer at 3/8 in or 1/2 in with no separate finish-coat bag: area ÷ 22 or ÷ 16.5. Metal lath is expanded diamond-mesh lath in sheets of 27 × 96 in, 18 sq ft each, over the same area with the same waste, which also covers the laps. These are planning figures: real coverage depends on how flat the wall is, how the mix is applied, how much is lost on the ground and how the mix is batched. Corner beads, casing beads, weep screed, water-resistive barrier, fasteners, color and sealer are not counted. The metric toggle shows lengths in m and areas in m².

QUIKRETE, Stucco Selector Guide: an 80 lb bag of One Coat Fiberglass Reinforced Stucco and of Scratch and Brown Base Coat Stucco covers about 20 to 24 sq ft at 3/8 in (found through search; the file itself could not be opened by the tool, so figures were checked from the search summary)
QUIKRETE, Base Coat Stucco, Pump Grade (1139-86) data sheet: 20 to 24 sq ft per 80 lb bag at 3/8 in
QUIKRETE, Finish Coat Stucco (1201) data sheet: about 70 sq ft per 80 lb bag at 1/8 in; coverage varies with texture
Sakrete (Basalite) Scratch & Brown Stucco data sheet: 70 sq ft per 80 lb bag trowel-applied at 1/8 in, which is about 23 sq ft at 3/8 in and agrees with the Quikrete rate
ASTM C926, Standard Specification for Application of Portland Cement-Based Plaster: 7/8 in total thickness for three-coat plaster over lath (found in an index of the standard; the split of 3/8 + 3/8 + 1/8 in is the usual one, not copied from the standard text)
Metal lath: expanded steel self-furring lath is sold in 27 × 96 in sheets, 20 sq yd (180 sq ft) to a bundle of 10, per Clark Dietrich, 1/4 in self-furring dimpled expanded steel plaster and stucco base
Waste of 10% and 20% are estimates of ours, not maker figures: plan more for rough, out-of-plane walls and spray application

How to calculate how many bags of stucco you need

Measure the walls. Add up the length of every wall all the way round and measure the wall height from the weep screed to the top of the stucco.
Subtract openings. Measure each door, window and garage door, width times height, and subtract the total from the wall area.
Add waste. Add 10% for a straight wall, more for a rough wall, spray application or many openings.
Pick the system. Three-coat is scratch and brown at 3/8 in each plus a 1/8 in finish, 7/8 in in all. One-coat is a single layer, about 3/8 to 1/2 in.
Divide by the coverage of a bag. Divide the area by the coverage printed on the bag, about 22 sq ft at 3/8 in for base coat (two coats make 11 sq ft per bag) and about 70 sq ft at 1/8 in for finish, and round up. Metal lath is the same area over 18 sq ft per sheet.

Worked examples

Project	Result
125 ft of wall, 9 ft high, three-coat, 10% waste	1,125 sq ft + 10% → 113 bags of base coat (57 scratch, 56 brown) + 18 finish = 131 bags, 69 sheets of lath
The same house with six 3 × 4 ft windows, two 3 × 6.7 ft doors and a 9 × 7 ft garage door	949.8 sq ft + 10% → 95 bags of base coat + 15 finish = 110 bags, 59 sheets of lath
The same house, one-coat stucco at 3/8 in	1,125 sq ft + 10% → 57 bags of one-coat mix, 69 sheets of lath
The same house, one-coat stucco at 1/2 in	1,125 sq ft + 10% → 75 bags of one-coat mix, 69 sheets of lath
A shed: 60 ft of wall, 8 ft high, three-coat, 20% waste	480 sq ft + 20% → 53 bags of base coat + 9 finish = 62 bags, 32 sheets of lath

Frequently asked questions

How many bags of stucco do I need?: Work out the wall area (length × height less openings), add waste, and divide by what a bag covers. For three-coat stucco a bag of base coat covers about 22 sq ft at 3/8 in, so two coats of it cover 11 sq ft of wall per bag, plus finish coat at about 70 sq ft per bag. The example house, 1,125 sq ft, with 10% waste comes to 113 bags of base coat and 18 of finish: 131 bags.
How much does an 80 lb bag of stucco cover?: Quikrete states about 20 to 24 sq ft at 3/8 in for its 80 lb base coat stucco (scratch and brown and one-coat mixes) and about 70 sq ft at 1/8 in for its finish coat. Sakrete lists 70 sq ft at 1/8 in for its scratch and brown mix. Coverage varies with texture and application, so use the number on your bag.
How thick is three-coat stucco?: About 7/8 in over lath: a scratch coat of 3/8 in, a brown coat of 3/8 in and a finish coat of 1/8 in. The total thickness is in ASTM C926; the split between coats is the usual one. A one-coat system is a single layer, typically 3/8 to 1/2 in thick.
What is the difference between three-coat and one-coat stucco?: Three-coat is a scratch coat, a brown coat and a finish coat, applied over lath, with curing time between coats. One-coat is a single pass of a fiber-reinforced mix. It is thinner and quicker, and uses fewer bags: for the example house 57 bags at 3/8 in against 113 for the base coats of three-coat, with no finish-coat bag. Check the product data sheet: one-coat systems have their own lath and substrate requirements.
Does a thicker coat use more stucco?: Yes, in proportion. At 1/2 in a bag covers about three-quarters as much as at 3/8 in, so the example house needs 75 bags of one-coat at 1/2 in against 57 at 3/8 in. This is geometry, not a maker's figure: the data sheet's own rate at your thickness wins.
How much waste should I add for stucco?: This calculator offers 10% and 20%. These are estimates of ours, not maker numbers. Stucco is lost on the ground, in the mixer and in thicker patches over out-of-plane walls, and spraying loses more than troweling. A small shed 60 ft round and 8 ft high at 20% waste needs 62 bags in all. Buying a few extra bags is cheaper than running short mid-wall, since a coat that stops partway can show as a line.
Do I subtract windows and doors?: Yes, enter each as an opening. On the example house, six 3 × 4 ft windows, two 3 × 6.7 ft doors and a 9 × 7 ft garage door take off 175.2 sq ft, leaving 949.8 and 110 bags in all instead of 131. The returns around the openings take extra material, which the waste percentage covers.
How much metal lath do I need?: Stucco goes over metal lath on wood framing and sheathing. Lath comes in sheets of 27 × 96 in (18 sq ft); the calculator counts them over the same area with the same waste, which also covers the laps: 69 sheets for the example house. Over solid masonry or concrete, lath may not be needed. Lath fasteners, weep screed, corner bead and the water-resistive barrier are separate.
Why do the manufacturers give a range, and which end should I use?: The 20 to 24 sq ft range reflects how the mix is placed and how flat the wall is. At 20 sq ft the example house needs 124 bags of base coat, at 24 sq ft 104; the calculator uses 22 (113). Use the low end for a rough wall or spray, the high end for a flat one with experienced hands.
Is this a bag of stucco or of mortar mix?: Stucco mix is a different blend from the bagged mortar or concrete mix you may also buy in 80 lb bags: it is a graded sand and cement made for plastering. See the concrete bags calculator for concrete, and the bricks calculator for mortar. Use the product the maker names for the substrate.

Handy tools

Feet and Inches Calculator: Add up tape-measure readings in feet, inches and fractions into the decimal feet the fields take.