Mortar, Brick & Block Calculator
Unit count and mortar bags for brick or CMU block walls. Per-square-foot constants account for 3/8" mortar joints.
Units needed
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— each
Net wall area
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ft²
Mortar (80-lb bags)
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Sand
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tons (Type N)
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How masonry quantities are estimated
The trick is converting wall area to unit count. Modular brick face dimensions are 7-5/8" × 2-1/4", and with the 3/8" mortar joints standard in the US a single brick covers 32 in² — about 6.75 bricks per square foot of wall.
- Modular brick: 6.75 brick/ft² · ~7 bags Type N mortar / 1,000 brick
- 8×8×16 CMU: 1.125 block/ft² · ~3 bags Type N / 100 block
- 12×8×16 CMU: 1.125 block/ft² · ~4 bags Type N / 100 block (larger joints)
Type N mortar (1:1:6 cement:lime:sand) is the most common general-purpose mix — works for above-grade brick and block in most climates. Type S goes below grade or where wind loads are heavy. Type M for structural CMU and retaining walls.
Mortar yield
An 80-lb bag of pre-blended Type N mortar yields about 1 cubic foot of finished mortar. A 60-lb bag yields 0.75 ft³. Mason's sand goes about 1 ton per 7 bags of mortar mix.
Frequently asked questions
How many bricks are in a square foot of wall?
Modular brick (the most common US standard) runs 6.75 bricks per square foot of single-wythe wall, using 3/8" mortar joints. This accounts for the brick face dimension of 7-5/8" × 2-1/4" plus joint. Double-wythe walls double that count. King-size and engineer-size bricks have different coverage — always confirm the face dimension with your supplier.
What mortar type should I use for brick and block?
Type N (1:1:6 cement:lime:sand) is the standard for above-grade exterior brick and general CMU work. Type S is specified for below-grade masonry, retaining walls, and high wind-load applications — it's stronger and more water-resistant. Type M is for structural CMU in foundations and heavy loadbearing walls. Avoid Type N below grade where freeze-thaw cycles or soil contact are present.
How many 80-lb mortar bags do I need per 1,000 bricks?
Approximately 7 bags of pre-blended Type N mortar per 1,000 modular bricks (standard 3/8" joints). For 8×8×16 CMU block, plan on 3 bags per 100 block; for 12×8×16 block, use 4 bags per 100 block. These are standard yields — add the waste factor if your joints are thicker than 3/8" or the blocks have irregular dimensions.
How much waste factor should I add for brick?
5% for clean rectangular walls with few cuts. 10% for typical walls with window and door openings that require cut bricks at the jambs. 15% for walls with lots of corners, arches, or irregular openings. Always order at least one full pallet more than calculated — dye lots vary and you may not be able to match bricks later if you run short. Save extra brick for future repairs.
What is the difference between CMU 8×8×16 and 12×8×16?
The numbers are nominal face and depth dimensions (width × height × length in inches). 8×8×16 CMU is standard for most above-grade block walls — 8" wide and 16" long with 8" exposed face height. 12×8×16 is a 12" wide block used in thicker loadbearing walls, basement walls, and retaining walls where more mass or insulation is needed. Both use the same mortar joint size and similar coverage rates per square foot.