What This Concrete Block Calculator Does

Feature	Description
Wall Dimensions	Length, height with unit toggle (imperial/metric)
Block Sizes	5 common sizes (16×8, 12×6, 20×8, 16×4, 8×8)
Wall Type	Single (4″), Double (8″), Triple (12″) thickness
Openings	Doors and windows area subtraction
Waste Factor	Adjustable 0-30% for breakage and cuts
Cost Estimation	Price per block × total blocks
Mortar Calculation	~0.75 cu ft per 100 blocks

Block Coverage Reference

Block Size	Coverage (sq ft)	Blocks per 100 sq ft
16″ × 8″	0.89	~112
12″ × 6″	0.50	~200
20″ × 8″	1.11	~90
16″ × 4″	0.44	~227
8″ × 8″	0.44	~227

Example Calculation

Wall: 20 ft long × 8 ft high

Parameter	Value
Gross Wall Area	160 sq ft
Door (3′×7′)	21 sq ft
Windows (2 × 3′×4′)	24 sq ft
Net Area	115 sq ft
Blocks Needed (16×8)	130 blocks
With 10% waste	143 blocks
Mortar Needed	~1.1 cu ft

How to Use

1. Select Unit System — Imperial (ft/in) or Metric (m/cm)
2. Enter Wall Dimensions — Length and height
3. Select Block Size — Choose from common sizes
4. Select Wall Type — Single, Double, or Triple thickness
5. Enter Openings — Number and size of doors/windows
6. Set Waste Factor — Typically 5-10%
7. Enter Block Price — For cost estimation
8. View Results — Total blocks, cost, mortar needed

Wall Types

Type	Thickness	Use Case
Single	4″/100mm	Garden walls, partitions
Double	8″/200mm	Load-bearing walls, houses
Triple	12″/300mm	Retaining walls, commercial

Mortar Estimation

• Standard estimate: 0.75 cubic feet per 100 blocks
• For metric: ~0.021 cubic meters per 100 blocks
• Factors that increase mortar: larger joints, irregular blocks

Waste Factor Guide

Factor	Scenario
5%	Simple straight walls, experienced mason
10%	Standard walls with some cuts (recommended)
15%	Complex walls with many corners
20%+	Inexperienced DIY, odd shapes

Keyboard Shortcuts

• Ctrl/Cmd + Enter — Recalculate
• Ctrl/Cmd + R — Reset to defaults