Concrete Block Calculator – CMU & Cinder Block Estimator
Our concrete block calculator tells you exactly how many concrete masonry units (CMU) you need, plus mortar bag estimates — so you order the right amount and stay on budget.
Concrete Block Calculator
Concrete Block Sizes Reference
| Block Type | Nominal Size | Blocks/Sq Ft |
|---|---|---|
| Standard CMU | 8×8×16″ | 1.125 |
| 4 inch Partition | 4×8×16″ | 0.75 |
| 12 inch Heavy | 12×8×16″ | 1.125 |
Frequently Asked Questions
How many blocks per square foot?
A standard 8×8×16″ block covers ~0.89 sq ft — so you need ~1.125 blocks per sq ft. Always add 10% for waste.
Cinder block vs concrete block?
Modern CMU (concrete masonry units) use Portland cement — stronger and more durable than old cinder blocks. The terms are used interchangeably today.
How much mortar do I need?
One 60 lb bag of mortar covers 30–35 standard blocks.