Blocks Needed
350 blocks
Wall Area
320 sq ft
Net Area
296 sq ft
Cost
$875
350
$875
320 sq ft
296 sq ft
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Price as of Jun 27, 2026. Product prices and availability are accurate as of the date indicated and are subject to change. Any price and availability information displayed on Amazon at the time of purchase will apply.
Inputs
Result
Wall area = 40 × 8 = 320 sq ft. Openings = 2 × 3 × 4 = 24 sq ft. Net = 296 sq ft. Blocks = 296 / 0.89 = 333, with 5% waste = 349. Cost = 349 × $2.50 = $828.
Inputs
Result
Wall area = 20 × 4 = 80 sq ft. No openings. Blocks = 80 / 0.89 = 90, with 5% waste = 95. Cost = 95 × $3.50 = $333.
A standard 8×8×16 CMU block covers 0.89 sq ft including mortar joints (8" height + 3/8" joint = 8.375", 16" length + 3/8" = 16.375"). So you need about 1.125 blocks per sq ft.
| Block Size | Face Area (with joints) | Blocks per sq ft | Avg Cost per Block |
|---|---|---|---|
| 4×8×16 | 0.89 sq ft | 1.125 | $1.50–$2.00 |
| 6×8×16 | 0.89 sq ft | 1.125 | $2.00–$2.75 |
| 8×8×16 | 0.89 sq ft | 1.125 | $2.50–$3.50 |
| 12×8×16 | 0.89 sq ft | 1.125 | $3.50–$5.00 |
Subtract the opening area from the total wall area before calculating blocks. For a 3 ft wide by 4 ft tall window, subtract 12 sq ft. This calculator handles multiple openings automatically.
Use 5% for simple straight walls, 7-10% for walls with corners and openings, and 10-15% for complex layouts. Breakage during delivery and cutting around openings accounts for most waste.
| Wall Complexity | Waste Factor | Common Sources of Waste |
|---|---|---|
| Simple straight wall | 5% | Minor breakage during delivery |
| Wall with 1–2 corners | 7–8% | Corner cuts, minor breakage |
| Wall with openings | 8–10% | Cuts around doors/windows |
| Complex layout | 10–15% | Multiple cuts, angles, curves |
Material cost alone is about $2.80-$4.00 per sq ft for blocks ($2.50-$3.50 per block at 1.125 blocks/sq ft). With mortar and labor, installed cost ranges from $10-$17 per sq ft.
| Cost Component | Per sq ft | Per 100 sq ft Wall |
|---|---|---|
| Blocks only | $2.80–$4.00 | $280–$400 |
| Mortar | $0.50–$1.00 | $50–$100 |
| Rebar / fill | $0.75–$1.50 | $75–$150 |
| Labor (mason) | $6.00–$10.00 | $600–$1,000 |
| Total installed | $10–$17 | $1,000–$1,700 |
Read our guide
Read our guide
Read our guide
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Last Updated: Jul 13, 2026
This calculator is provided for informational and educational purposes only. Results are estimates and should not be considered professional financial, medical, legal, or other advice. Always consult a qualified professional before making important decisions. UseCalcPro is not responsible for any actions taken based on calculator results.
