Comprehensive Brick, Concrete Block (CMU) & Mortar Estimator
Whether laying standard red clay face bricks for an exterior facade, building a structural concrete block (CMU) foundation wall, setting stone veneer, or mixing custom mortar on-site, precise material estimation is essential. Under-ordering mortar leads to delayed jobs and color-matching variations between batches, while miscalculating brick counts leads to expensive pallet re-orders or thousands of dollars in leftover masonry units.
This calculator accurately estimates total brick and block counts, pre-mixed mortar bags (70 lb and 80 lb), core grout volume for hollow CMU cells, and site-mixed raw ingredients (Portland cement, hydrated lime, and masonry sand) adhering to ASTM C270 specifications.
Standard Brick & Block Size Reference Table
Masonry dimensions are expressed as specified dimensions (actual manufactured size) and nominal dimensions (which include the standard 3/8″ or 10 mm mortar joint). The table below lists the standard masonry units and their coverage factors:
| Masonry Unit Type | Actual Dimensions (D × H × L) | Nominal Dimensions | Units per Sq Ft | Units per 100 Sq Ft |
|---|---|---|---|---|
| Standard Modular Brick | 3-5/8″ × 2-1/4″ × 7-5/8″ | 4″ × 2-2/3″ × 8″ | 6.75 | 675 bricks |
| Standard / Common Brick | 3-3/4″ × 2-1/4″ × 8″ | 4″ × 2-2/3″ × 8-3/8″ | 6.55 | 655 bricks |
| Queen Size Brick | 2-3/4″ × 2-3/4″ × 9-5/8″ | 3-1/8″ × 3-1/8″ × 10″ | 5.75 | 575 bricks |
| King Size Brick | 2-5/8″ × 2-5/8″ × 9-5/8″ | 3″ × 3″ × 10″ | 4.75 | 475 bricks |
| Utility Brick | 3-5/8″ × 3-5/8″ × 11-5/8″ | 4″ × 4″ × 12″ | 3.00 | 300 bricks |
| Standard 8″ CMU Block | 7-5/8″ × 7-5/8″ × 15-5/8″ | 8″ × 8″ × 16″ | 1.125 | 113 blocks |
| 6″ CMU Partition Block | 5-5/8″ × 7-5/8″ × 15-5/8″ | 6″ × 8″ × 16″ | 1.125 | 113 blocks |
| 12″ CMU Foundation Block | 11-5/8″ × 7-5/8″ × 15-5/8″ | 12″ × 8″ × 16″ | 1.125 | 113 blocks |
ASTM C270 Mortar Types: Selection & Mix Ratios
Under ASTM C270 (Standard Specification for Mortar for Unit Masonry), mortar is classified into four primary types designated by alternating letters in the phrase M-a-S-o-N w-O-r-K:
Type M
High Compressive Strength
Best for: Foundation walls, retaining walls, basement masonry, below-grade structures, and heavy structural piers.
Mix Ratio: 1 part Portland Cement : 1/4 part Hydrated Lime : 3 to 3.75 parts Sand.
Type S
High Flexural Bond Strength
Best for: Exterior walls exposed to high wind or seismic loads, at-grade paving, shallow retaining walls.
Mix Ratio: 1 part Portland Cement : 1/2 part Hydrated Lime : 4 to 4.5 parts Sand.
Type N
General Exterior Masonry
Best for: Above-grade exterior facades, chimneys, outdoor fireplaces, and residential brick veneer.
Mix Ratio: 1 part Portland Cement : 1 part Hydrated Lime : 5 to 6 parts Sand.
Type O
Low Strength / Flexible
Best for: Interior non-loadbearing walls, historic preservation, and tuckpointing soft antique brick.
Mix Ratio: 1 part Portland Cement : 2 parts Hydrated Lime : 7 to 9 parts Sand.
Mortar Usage Estimation Rules of Thumb
How much mortar do you need for a given project? The Brick Industry Association (BIA) and National Concrete Masonry Association (NCMA) publish standard consumption benchmarks:
- For Standard Clay Bricks:
- Laying 1,000 standard modular bricks requires approximately 7.0 to 7.5 bags (80 lb) of pre-mixed masonry mortar (or ~10 cu ft of wet mortar).
- For every 100 bricks, budget roughly 0.75 bags of 80-lb pre-mix mortar.
- Site-mix: 1,000 modular bricks requires ~1,000 lbs of sand, 3 bags of masonry cement (or 2 bags Portland + 1 bag lime).
- For 8″ Concrete Blocks (CMU):
- Laying 100 standard 8″ CMU blocks (face-shell bedded) requires approximately 3.0 to 3.5 bags (80 lb) of pre-mixed mortar.
- For full-bed mortar (head and bed joints fully mortared), budget 4.0 bags per 100 blocks.
- CMU Core Grout Fill:
- A standard hollow 8″ CMU block has 2 internal cells. Filling both cells completely requires approximately 0.30 cubic feet of concrete grout per block.
- 1 cubic yard (27 ft³) of pea-gravel grout fills approximately 85 to 90 standard 8″ blocks.
Frequently Asked Questions
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