Brick & Block Calculator

How to Estimate Bricks and CMU Blocks

Accurate masonry estimating prevents costly delays and over-ordering. The process starts with calculating the net wall area — gross wall area minus openings such as doors and windows. A standard door opening is approximately 21 square feet (3 ft x 7 ft), while a typical window is about 15 square feet (3 ft x 5 ft).

Once you have the net area, divide by the area of a single unit including the mortar joint. For an 8x8x16 CMU with a 3/8" mortar joint, each block covers about 0.93 square feet. Always add a waste factor of 5-10% to account for breakage, cuts, and misalignment.

Mortar and Sand Requirements

Mortar is the binding material between masonry units. For CMU block walls, plan for about 7 bags of 60-pound mortar mix per 100 square feet of wall surface. For standard bricks with their smaller joints and more units per area, expect roughly 10.5 bags per 100 square feet. Sand requirements average about 1.5 cubic feet per 100 square feet when using pre-mixed mortar.