Concrete Block Calculator
Use this concrete block calculator to estimate the number of blocks and mortar bags required to build a wall based on your project’s dimensions.
Input Parameters
Block Calculator
Mortar Calculator
Typically measured in inches
Standard block size: 16″ x 8″ x 8″
Typical mortar joint: 0.5 inches
Typical waste factor: 15%
Typical dry factor: 25% (1.25 multiplier)
Leave blank to calculate from block count
Calculation Results
Wall Volume:
0.00 ft³
Block Volume:
0.00 ft³
Block with Mortar Volume:
0.00 ft³
Number of Blocks Needed:
0
Total Block Volume:
0.00 ft³
Mortar Volume:
0.00 ft³
Mortar Volume with Waste:
0.00 ft³
Dry Mortar Volume:
0.00 ft³
Cement Volume:
0.00 ft³
Cement Bags Needed:
0
Sand Volume:
0.00 ft³
Sand Weight:
0.00 lbs
How to Use This Calculator?
- Enter wall dimensions (length, height, thickness) in your preferred units
- Enter block dimensions (standard blocks are typically 16″ x 8″ x 8″)
- Set mortar joint thickness (typically 0.5 inches)
- Adjust waste factor to account for breakage and cuts
- For mortar calculations, you can either calculate from block count or enter mortar volume directly
- Adjust cement and sand ratios for your specific mortar mix (common ratios are 1:3 or 1:4)
Calculation Formulas Used:
Wall Volume = Length × Height × Thickness
Block Volume = Length × Height × Width
Block with Mortar Volume = (Length + Mortar Joint) × (Height + Mortar Joint) × (Width + Mortar Joint)
Number of Blocks = Wall Volume / Block with Mortar Volume
Total Block Volume = Number of Blocks × Block Volume
Mortar Volume = Wall Volume – Total Block Volume
Mortar with Waste = Mortar Volume × (1 + Waste Factor)
Dry Mortar = Mortar with Waste × 1.25
Cement Volume = (Cement Ratio / (Cement Ratio + Sand Ratio)) × Dry Mortar
Cement Bags = Cement Volume / 0.035
Sand Volume = (Sand Ratio / (Cement Ratio + Sand Ratio)) × Dry Mortar
Sand Weight = Sand Volume × 100 lbs/ft³