CMU Block & Accessories Calculator

How to use it

1. 1

   Enter the total wall length and the wall height in feet, and the number of corners and wall ends.

2. 2

   Pick the block width and add any door and window openings with their sizes and quantities.

3. 3

   Choose the grout pattern, bond beam courses, and the vertical bar spacing and sizes from the structural drawings.

4. 4

   Open Assumptions to adjust waste, mortar and grout rates to your company standards.

5. 5

   Read the quantities off the results table, or upload your plans for a full masonry takeoff.

How the numbers are calculated

Block count

A standard CMU has a nominal 8 x 16 in face, so one unit covers 0.889 SF and a wall takes 1.125 units per SF (112.5 per 100 SF). Net wall area is length x height minus openings.

Courses

Courses are wall height in inches divided by 8, rounded up. Corner and end units are counted as one per course at each corner or end.

Bond beams and lintels

Each bond beam course uses one bond beam unit per 16 in of wall length. Lintels span the opening width plus 8 in of bearing on each side, at one lintel unit per 16 in.

Grout

Grout is the fully grouted rate for the block width per 100 SF, scaled by the share of cells filled. Cells sit 8 in on center, so grouting every 32 in fills one cell in four. Bond beam courses are added as fully grouted strips.

Mortar

Mortar is calculated as bags per 100 units, a common rule of thumb for masonry cement. Set the rate to match your mix and bag size.

Reinforcing

Vertical bars are placed at the chosen spacing plus one at the wall end, each bar the wall height plus the lap allowance. Bars are rounded up to whole stock lengths. Bond beams carry two bars per course. Horizontal joint reinforcement runs every second course with a 10 percent lap allowance.