Concrete Block Quantity Calculator
Calculate concrete block quantity with clear inputs, formula guidance, and practical result checks.
Concrete Block Quantity measurements
Enter your values, then calculate.
Result
How to calculate concrete block quantity
This calculator estimates how many concrete masonry units (CMU blocks) you need for a wall, based on the wall's total area and how much area a single block covers.
How the calculation works
Blocks needed = ceil(Wall area ÷ Block coverage). Standard 8x8x16-inch CMU blocks (including a typical mortar joint) cover about 0.89 sq ft each; dividing total wall area by your block's coverage and rounding up gives a whole-block count.
Example
A wall with 400 sq ft of area, using standard CMU blocks covering 0.89 sq ft each: ceil(400 ÷ 0.89) = ceil(449.4) = 450 blocks.
Frequently asked questions
How much does a standard concrete block cover?
A standard 8x8x16-inch CMU block, accounting for typical mortar joints, covers roughly 0.89 square feet of wall area. This works out to about 112-113 blocks per 100 square feet of wall.
Should I subtract window and door openings?
Yes, for a more accurate count — subtract the area of any openings from your total wall area before running this calculation, since block isn't needed where there's no wall.
Concrete Block Quantity Calculator
Blocks needed = ceil(Wall area ÷ Block coverage). Standard 8x8x16-inch CMU blocks (including a typical mortar joint) cover about 0.89 sq ft each; dividing total wall area by your block's coverage and rounding up gives a whole-block count.
Let's understand your concrete block quantity result.
Calculate a result above and this guide will help you interpret it using this calculator's own formula and explanation.
Pro Tips for Concrete Block Quantity
- Standard 8x8x16 CMU blocks (with typical mortar joints) work out to roughly 112.5 blocks per 100 sq ft, or about 0.89 sq ft coverage per block — confirm this matches your specific block size before ordering.
- Add 5-10% extra for cuts, corners, and breakage, especially on walls with many openings or corners requiring block cuts.
- Subtract door and window openings from your wall area first for a tighter estimate, since block isn't needed across open spans.
Common Concrete Block Quantity Mistakes to Avoid
- Using the standard 0.89 sq ft coverage figure for a non-standard block size — larger or smaller CMU blocks have different coverage rates and will produce an inaccurate count if you don't adjust.
- Skipping a waste allowance, which usually results in running short since cutting blocks around corners and openings creates unusable partial pieces.
When to Use This Calculator
This calculator estimates how many concrete masonry units (CMU blocks) you need for a wall, based on the wall's total area and how much area a single block covers.