Calculated result
173blocks
Blocks to order
Formula
MAS-CMU-001139 ft²
Net wall area
0.889 ft²
Nominal face area
156.4 blocks
Mathematical quantity
Masonry calculator
Concrete block calculator
CMU count and mortar-bag planning from wall area, opening deductions and nominal block face size.
Reviewed formula · v1.0.0
Project inputs
Enter field measurements. Unit conversion happens before the reviewed formula is applied.
All values can be refined when you edit the estimate. This tool does not replace field verification or local requirements.
Transparent cost view
Use visible planning values, then replace them with actual job costs before quoting.
Material cost$14,705
Direct cost$15,095
Overhead + contingency$1,510
Markup + tax$1,993
Estimated project total$18,597
How this calculator works
A transparent concrete block calculator takeoff.
This calculator divides net wall area by the selected nominal CMU face, which already includes the mortar joint, then rounds whole blocks and mortar bags after a visible allowance.
Worked example. Example: a 20 ft × 8 ft wall with one 21 ft² door has 139 ft² of net area. Standard 8 × 16 in nominal blocks cover 0.889 ft² each, so 173 blocks are purchased after 10% waste and 6 mortar bags at 33 blocks per bag.
- 1. Measure finished wall length and height.
- 2. Deduct actual door and window openings.
- 3. Use the nominal block face that matches the selected unit, then confirm mortar yield on the bag.
Need the broader workflow? Read the masonry planning guide.
Questions
Common questions about this concrete block calculator.
Does nominal size include mortar?
Yes. An 8 × 8 × 16 in nominal CMU is planned on an 8 × 16 in face that already includes a typical mortar joint.
Does this fill block cores?
No. Grout fill, bond beams, lintels and reinforcement are separate takeoffs.