Concrete Block Calculator
Calculate concrete blocks, mortar, and grout for your wall project.
Last updated: January 15, 2026
Enter Wall Details
Above-grade exterior walls
标准承重墙 — Standard load-bearing walls
% (5% recommended)
Type S for load-bearing walls, Type N for non-structural
Results
Blocks Needed
189
180 blocks + 5% waste
Wall Area
160 sq ft
Mortar: 17 bags (80lb)
Cost Estimate
Blocks:$283.5
Mortar:$136
Labor:$378
TOTAL: $797.5
*Estimate only. Actual costs vary by location and contractor.
Shopping Tips
- • 189 blocks ≈ 3 pallets (standard: 90-100 blocks/pallet)
- • 17 mortar bags — available at Home Depot/Lowe's
- • Blocks sold individually or by pallet at most suppliers
How to Use This Calculator
- Select your project type — Foundation, retaining wall, interior, or exterior. The calculator will suggest the right block size.
- Choose CMU block size — 8×8×16 is standard for most walls. Use 12×8×16 for foundations, 6×8×16 for interior partitions.
- Enter wall dimensions — Length and height in feet or inches. The calculator uses actual block dimensions (7⅝×7⅝×15⅝ for 8×8×16).
- Add mortar and grout — Mortar is required for all walls. Grout is needed for load-bearing and foundation walls.
- Get your estimate — Review block count, mortar bags, grout volume, and total cost. Remember to get contractor quotes before starting.
How We Calculate
Blocks = Wall Area (sq ft) × Blocks per sq ft × (1 + Waste%)
Standard 8×8×16 blocks: 1.125 blocks per square foot
CMU Sizes (ASTM C90)
- • 4×8×16: 1.125 blocks/sq ft
- • 6×8×16: 1.125 blocks/sq ft
- • 8×8×16: 1.125 blocks/sq ft (standard)
- • 10×8×16: 1.125 blocks/sq ft
- • 12×8×16: 1.125 blocks/sq ft
Mortar Requirements
- • 8×8×16 blocks: 8.5 bags/100 blocks
- • Type S: Load-bearing walls
- • Type N: Non-structural walls
- • 80lb bags (Type S or Type N)
Example: 20×8 ft Wall with 8×8×16 Blocks
- Wall Area: 20 × 8 = 160 sq ft
- Blocks: 160 × 1.125 = 180 blocks
- With 5% waste: 180 × 1.05 = 189 blocks
- Mortar: (180 ÷ 100) × 8.5 = 16 bags
- Grout (full fill): 180 × 0.5 = 90 cu ft (3.3 cu yd)
Calculations based on ASTM C90 (CMU standards) and NCMA TEK 1-1F guidelines. Learn more