Stucco Coverage Calculator
Wall area + scratch/brown/finish coat thickness → bags of stucco mix needed (3-coat system).
Result
- Wall area500 ft²
- System3-coat (~⅞" total)
- Base-coat coverage30 ft² per 80-lb bag
- Base bags (with waste)19 × 80-lb
- Finish-coat coverage80 ft² per 80-lb bag
- Finish bags (with waste)7 × 80-lb
- Total bags26 × 80-lb
- Metal lath sheets (~18 ft² each)Required for wood/metal-frame walls (3-coat over lath).28
Step-by-step
- Base coat: 500 / 30 = 16.67 bags; × 1.10 = 19 (rounded up).
- Finish coat: 500 / 80 = 6.25 bags; × 1.10 = 7 (rounded up).
- Total bags = 26.
How to use this calculator
- Enter total wall area in ft².
- Pick the coat system based on your substrate.
- Set waste factor (10% typical, more for cut-up walls).
About this calculator
Stucco material requirements depend on the system. A 3-coat (scratch + brown + finish) totaling about ⅞" is the traditional Portland-cement system installed over metal lath on wood-frame walls. A 2-coat system at ⅜-½" goes directly over masonry or concrete. 1-coat (proprietary, polymer-modified) covers in a single ⅜" application. Per-bag coverage figures here are from Quikrete and La Habra published spec sheets.
What this calculator does
This calculator returns the number of 80-lb stucco-mix bags required for a wall area, broken into base-coat and finish-coat counts based on the chosen system (3-coat traditional, 2-coat over masonry, or 1-coat proprietary). Coverage figures are from major stucco-mix manufacturers (Quikrete, La Habra) and a waste factor is applied so the result is the actual purchase quantity, not the net consumed.
How it works — the formula
base_bags = ceil((area / base_coverage) × (1 + waste))
finish_bags = ceil((area / finish_coverage) × (1 + waste)) (zero for 1-coat)
lath_sheets = ceil(area / 18 ft² per sheet) (3-coat only)Per-bag coverage is set by mix thickness × consumed-volume per ft². At ⅜" thickness an 80-lb bag covers ~30 ft² of base; the thinner ⅛" finish coat stretches one bag to ~80 ft². Industry waste factors of 10-20% account for mixing-bowl losses, trowel waste, and substrate absorption.
Worked examples
- Inputs:
- area=500, system=3coat, waste=10%
- Output:
- ~18 base bags + 7 finish bags = 25 total; 28 lath sheets
Standard new-construction stucco residence.
- Inputs:
- area=300, system=2coat, waste=10%
- Output:
- ~7 base bags + 5 finish bags = 12 total; no lath needed
Common for CMU retaining walls and accessory buildings.
- Inputs:
- area=400, system=1coat, waste=10%
- Output:
- ~13 bags total
Polymer-modified 1-coat over an existing prepared substrate.
When to use this vs other tools
Use this for stucco materials estimating. Related construction-material tools cover concrete and mortar with the same methodology.
- Concrete Volume
Use to estimate concrete for slab/footing — different math but same materials-estimating discipline.
- Mortar Bag Yield
Use for masonry mortar quantities (CMU/brick laying), the parallel calculation to stucco.
- Mortar Mix
Use to compute Portland-cement + lime + sand quantities for site-mixed mortar by ASTM type.
Authority note
Major stucco-mix manufacturers publish per-bag coverage figures based on mix thickness. The IRC (International Residential Code) Section R703.7 sets the wall-system requirements for exterior stucco; coverage math anchors on the manufacturer spec sheets.
Limitations
- Coverage values are nominal. Highly-absorbent substrates (rough CMU, lath wraps) consume more material.
- Doesn't account for non-stucco accessories (corner aid, control joints, foundation weep screed) — separate take-off.
- Site-mixed stucco yields vary with sand gradation and water content; use bagged-mix coverage as a baseline.
- Multi-coat systems often have a curing/moist-cure schedule between coats; this calculator addresses quantity only.
For commercial-quality stucco, follow manufacturer instructions and the IRC. Hire a licensed applicator for stucco over wood-frame walls.