Concrete Block Calculator — Concrete-Depot.com

Calculate blocks, mortar, core fill, and rebar for your CMU wall project with live 3D visualization.

Wall Length (ft) Total length of the wall

Wall Height (ft) Total height of the wall

Block Size

Mortar Joint (in) Standard ⅜″

Doors to Deduct 21 sq ft each

Windows to Deduct 15 sq ft each

Waste Factor (%)

Core Fill

Block Price ($/block) Leave 0 to skip cost

Concrete Blocks Needed –

Wall Area (net) –

Blocks per Sq Ft –

Mortar Bags (60 lb) –

Mortar Bags (80 lb) –

Core Fill Concrete –

Vertical Rebar (#4) –

Total Courses –

Estimated Cost –

With Waste Factor –

How to use

1. Enter your wall length and height in feet.

2. Select your block size or enter custom dimensions.

3. Adjust mortar joint thickness if different from standard ⅜″.

4. Enter the number of doors and windows to deduct from the total area.

5. Select your waste factor based on wall complexity.

6. Choose core fill option if building a structural or retaining wall.

7. View the live 3D wall visualization and results below.

Formula used

Wall Area: Length × Height − (Doors × 21) − (Windows × 15)

Blocks per Sq Ft: 1 ÷ ((Block Length + Joint) × (Block Height + Joint) ÷ 144)

Total Blocks: Wall Area × Blocks per Sq Ft × (1 + Waste%)

Mortar Bags: Total Blocks ÷ 37 (for 60lb) or ÷ 48 (for 80lb)

Core Fill Volume: Blocks × Cores per Block × Core Volume ÷ 27