Stucco calculator: how many bags of stucco do I need?
27 bags
270 sq ft at 10 to 12 sq ft per 80 lb bag · 23 to 27 bags across that range · for 30 × 9 ft, 3/4 in
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3/8 or 10' 6".
27 bags
270 sq ft at 10 to 12 sq ft per 80 lb bag · 23 to 27 bags across that range
Source: QUIKRETE Scratch and Brown Base Coat Stucco No. 1139 data sheet (revised October 2021), read October 20, 2026. Data sheet (PDF)
270 square feet of wall with a 3/4 inch base coat takes 27 bags of 80 lb stucco: Quikrete's Scratch and Brown data sheet gives 10 to 12 square feet per bag at that thickness, so the low end is 27.
A worked example
A 41 by 8.5 ft concrete block garden wall with a 1/2 inch base coat on one face needs 24 bags. The face is 348.5 square feet. At 15 square feet per bag that is 23.23, so 24 bags; at the 18 end of the chart it would be 20. The IRC asks at least 1/2 inch of plaster on masonry, which the base coat alone already gives.
How many square feet does an 80 lb bag of stucco cover?
20 to 24 square feet at 3/8 inch, 15 to 18 at 1/2 inch and 10 to 12 at 3/4 inch, by Quikrete's data sheet for its Scratch and Brown base coat. The high end of each row is the 0.75 cubic feet a bag yields spread at that thickness, so twice the thickness covers half the wall.
How thick does stucco have to be?
By Table R702.1(1) of the 2021 IRC, cement plaster is at least 7/8 inch thick over wire lath outdoors and at least 1/2 inch on masonry walls, and no more than 7/8 inch on monolithic concrete walls. It goes on in at least three coats over metal lath and at least two over masonry or concrete.
What else it is called
The base coat is the scratch coat and the brown coat, and the mix is also called cement plaster or portland cement plaster. Searched as a stucco calculator, stucco material calculator or stucco square feet calculator. The finish coat, Quikrete No. 1201, comes in its own bag.
Bags by area
| Area | 3/8 in (20-24 sq ft) | 1/2 in (15-18 sq ft) | 3/4 in (10-12 sq ft) |
|---|---|---|---|
| 8 × 8 ft | 3-4 | 4-5 | 6-7 |
| 10 × 10 ft | 5 | 6-7 | 9-10 |
| 10 × 12 ft | 5-6 | 7-8 | 10-12 |
| 12 × 12 ft | 6-8 | 8-10 | 12-15 |
| 12 × 16 ft | 8-10 | 11-13 | 16-20 |
| 16 × 20 ft | 14-16 | 18-22 | 27-32 |
| 20 × 20 ft | 17-20 | 23-27 | 34-40 |
QUIKRETE Scratch and Brown Base Coat Stucco (No. 1139), 80 lb bags, by its data sheet. Two figures are the bag count at the high and the low end of the coverage; buy the higher one. The finish coat is another product and is not counted.
Where the numbers come from
- Coverage per bag: the QUIKRETE Scratch and Brown Base Coat Stucco data sheet (No. 1139, revised October 2021), a base coat plaster to ASTM C926 for the scratch and brown coats of a 3-coat job or the first coat of a 2-coat job. An 80 lb bag yields about 0.75 cubic feet and covers 20 to 24 square feet at 3/8 inch, 15 to 18 at 1/2 inch and 10 to 12 at 3/4 inch. Read October 20, 2026. Data sheet (PDF)
- Thickness: Table R702.1(1) of the 2021 International Residential Code, cement plaster: at least 7/8 inch over wire lath outdoors, at least 1/2 inch on masonry walls, at most 7/8 inch on monolithic concrete walls; section R702.2.2 asks at least three coats over metal lath and two over other bases. Read in the 2021 Seattle Residential Code, chapter 7, which does not amend that table, October 20, 2026. Data sheet (PDF)
- The rest is arithmetic: square feet ÷ the low end of the chart at your thickness, rounded up, so the wall is not left short on the last bag.
This counts the base coat only. The finish coat is a separate product whose coverage this page has not read, so it is not in the count; windows and doors stay in unless you take their area off the wall.
By Javier Miralles · Last updated . How this site is made.
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