Home Calculators Concrete Block Calculator

Concrete Block Calculator

Calculate how many concrete blocks (CMU) you need for any wall project. Includes mortar, waste factor, and cost estimates for standard, corner, and specialty blocks.

Wall Dimensions

Enter your wall's length and height to calculate block requirements

Wall Measurements

Total length of the wall in feet

Total height of the wall in feet

Wall Area160 sq ft
Block Type & Size
Blocks per sq ft (this size)—
Openings & Deductions

Subtract doors, windows, and other openings from the total wall area.

Total Opening Area—
Project Settings & Cost

Typically 5–15%

~3 bags / 100 blocks

Blocks Needed
---
including waste
Mortar Bags
--
60-lb bags needed
Estimated Cost
$--
blocks + mortar
Net Wall Area
-- sq ft
after deducting openings

Standard CMU Specs

Size (nominal)8×8×16 in
Actual size7.625×7.625×15.625
Weight each~30–50 lbs
Blocks per sq ft~1.125
Pallets (144 blocks)Common unit

Waste Factor Guide

Simple straight wall5–7%
Wall with corners8–10%
Complex / curved12–15%
Inexperienced crew+5% extra

How the Calculation Works

Wall Area

Length × Height − Openings

Block Face Area

(W + joint) × (H + joint)

Base Blocks

Wall Area ÷ Block Face Area

With Waste

Base × (1 + waste%)