Brick and block mortar
Mortar calculator
A 100 sq ft wall of modular brick with ⅜ in. joints takes about 5.5 cubic feet of mortar before waste, or 6.33 ft³ with a 15% allowance, and about 675 bricks. Enter your wall, pick the brick or block and joint width, and the calculator gives mortar volume, bags of mortar mix and sand. Last updated October 12, 2026.
Mortar estimate
Measurement system: Imperial. Planning estimate from published masonry tables.
Estimate mortar for your wall
Enter the wall, choose the brick or block and the joint width.
Shaded gaps are the mortar joints the estimate fills. Diagram not to scale.
Net mortar plus your waste allowance.
WALL AND MORTAR BREAKDOWN
BAGS AND SAND
Quantities come from published masonry tables and rules of thumb, not from your exact bond, coring or workmanship. Mortar type comes from your plans; this does not choose it.
The method
Wall area × mortar per 100 sq ft, then add waste
The Brick Industry Association’s estimating method works from wall area. Its Table 4 gives the number of brick and the cubic feet of mortar for each 100 sq ft of wall, by brick size and joint thickness. Multiply by your net wall area (after doors and windows), then add a waste allowance. The table values are theoretical mortar volumes without waste.
For concrete block, the calculator uses NCMA’s figures: 112.5 blocks and about 8.5 ft³ of mortar per 100 ft² of 8 × 16 in. block wall. NCMA’s 8.5 already includes 10% waste, so the calculator removes that first and then applies your own allowance. At 10% it gives NCMA’s figure back.
Worked examples
Five mortar estimates, calculated step by step
- A 20 ft × 8 ft modular brick wall with a 21 ft² door, ⅜ in. joints. Net area 160 − 21 = 139 sq ft. Mortar 1.39 × 5.5 = 7.645 ft³; with 15% waste 8.79 ft³ (0.326 yd³). Bricks 1.39 × 675 = 938.25, or 986 with 5% breakage. At up to 37 bricks per 80 lb bag of mortar mix, plan for 30 bags.
- The same wall with ½ in. joints. 1.39 × 6.9 = 9.591 ft³ net, 11.03 ft³ with 15% waste: about 25% more mortar for the wider joint.
- The same wall in 8 × 16 in. concrete block. 139 sq ft × 8.5 ÷ 100 = 11.82 ft³ including NCMA’s 10% waste. That lays 156.4 blocks: 14 bags of 80 lb mortar mix at up to 13 blocks per bag, or 6 bags of 70 lb masonry cement and 0.75 tons of sand.
- 100 sq ft of standard (non-modular) brick. BIA lists 655 brick and 9.5 ft³ of mortar per 100 sq ft with ⅜ in. joints, which is 14.5 ft³ per 1,000 brick.
- A metric wall, 5 m × 2 m in modular brick. 10 m² = 107.64 sq ft; mortar 5.920 ft³ = 0.168 m³ net, 0.193 m³ with 15% waste.
These follow the published tables for running or stack bond. They are planning quantities, not a mortar specification.
Brick and mortar per 100 square feet
- Modular brick5.5 ft³
- Engineer modular brick4.8 ft³
- Closure modular brick4.1 ft³
- Roman brick6.4 ft³
- Norman brick5.1 ft³
- Utility brick3.7 ft³
- Queen brick6.7 ft³
- King brick6.5 ft³
- Standard brick9.5 ft³
| Brick | Size | Brick per 100 sq ft | Mortar ft³, ⅜ in. joint | Mortar ft³, ½ in. joint |
|---|---|---|---|---|
| Modular brick | 4 × 2⅔ × 8 in nominal | 675 | 5.5 | 6.9 |
| Engineer modular brick | 4 × 3⅕ × 8 in nominal | 563 | 4.8 | 6.1 |
| Closure modular brick | 4 × 4 × 8 in nominal | 450 | 4.1 | 5.2 |
| Roman brick | 4 × 2 × 12 in nominal | 600 | 6.4 | 8.2 |
| Norman brick | 4 × 2⅔ × 12 in nominal | 450 | 5.1 | 6.5 |
| Utility brick | 4 × 4 × 12 in nominal | 300 | 3.7 | 4.7 |
| Queen brick | about 2¾–3 × 2¾ × 7⅝–8 in specified | 550 | 6.7 | 7.4 |
| King brick | about 2¾–3 × 2⅝–2¾ × 9⅝–9¾ in specified | 455 | 6.5 | 7.3 |
| Standard brick | 3½–3⅝ × 2¼ × 8 in specified | 655 | 9.5 | 11.0 |
For multi-wythe walls with a mortared collar joint, BIA’s Table 5 adds 3.13 ft³ per 100 sq ft for a ⅜ in. collar joint and 4.17 ft³ for a ½ in. joint. Header bonds add brick and mortar using BIA’s correction factors; for example, common bond with full headers every fifth course adds 1/5 to the brick count and 1/15 to the mortar.
Bags, sand and mortar type
Preblended bagged mortar is the simplest route for small jobs. QUIKRETE’s datasheet for its Mortar Mix (product 1102) says an 80 lb bag lays up to 37 standard bricks or 13 standard blocks and meets ASTM C270 as Type N mortar. For other products, enter the yield from the bag into the calculator. If you mix your own, BIA’s rule of thumb is that one cubic foot of loose, damp sand makes about one cubic foot of mortar.
The mortar type, such as N or S, comes from your plans or building official. NCMA’s TEK 09-01A notes that codes typically require Types M, S or N, and that Types S or M are required in some cases, including empirically designed foundation walls and seismic design categories D, E and F. This calculator estimates quantity only.
Common questions
Mortar questions
How much mortar do I need for 100 square feet of brick?
For modular brick with ⅜ in. joints, BIA Technical Note 10 lists about 5.5 ft³ of mortar per 100 sq ft before waste, which is 6.33 ft³ with a 15% allowance. Standard brick takes more, about 9.5 ft³ per 100 sq ft, and ½ in. joints take more again.
How many bricks does a bag of mortar lay?
QUIKRETE’s datasheet for its Mortar Mix (product 1102, Type N) says one 80 lb bag lays up to 37 standard bricks or 13 standard 8 × 8 × 16 in. blocks. “Up to” is a best case, so add an allowance for waste.
How many bags of mortar do I need for 1,000 bricks?
At QUIKRETE’s up-to-37-bricks figure, 1,000 bricks need at least 28 bags of 80 lb mortar mix before waste. If you mix your own, BIA notes the masons’ rule of thumb of 8 bags of masonry cement per 1,000 modular brick, which already includes some waste. The table method gives 8.1 ft³ of mortar per 1,000 modular brick before waste.
How much mortar do I need per concrete block?
NCMA TEK 03-11 gives about 8.5 ft³ of mortar per 100 ft² of block wall with ⅜ in. joints, face shell bedding and 10% waste. With 112.5 blocks per 100 ft², that is about 0.076 ft³ per block. One 70 lb bag of masonry cement lays about 30 blocks (TEK 04-02A).
How much sand do I need for mortar?
BIA Technical Note 10 says one cubic foot of loose, damp sand yields about one cubic foot of mortar, so plan roughly as much sand as mortar. For block work with masonry cement, NCMA TEK 04-02A uses 1 ton of masonry sand per 8 bags of cement.
How much extra mortar should I order?
BIA recommends working out net quantities first, then adding 15 to 25 percent to the mortar and at least 5 percent to the brick for breakage and waste. Job conditions and experience can call for more.
Does joint thickness change how much mortar I need?
Yes. For modular brick, going from ⅜ in. to ½ in. joints raises the mortar from 5.5 to 6.9 ft³ per 100 sq ft, about 25% more. BIA lists the same 675 modular brick per 100 sq ft for both joint widths.
Should I use Type N or Type S mortar?
Use the type on your plans. NCMA TEK 09-01A notes that building codes typically require Types M, S or N. It also notes that Types S or M are required in some cases, such as empirically designed foundation walls and seismic design categories D, E and F. Bagged preblended mortar such as QUIKRETE Mortar Mix is commonly Type N; check the bag.
Sources and limits
Brick Industry Association, Technical Note 10, Dimensioning and Estimating Brick Masonry (February 2009): Tables 4, 5 and 6, waste guidance and rules of thumb. Concrete Masonry & Hardscapes Association TEK notes 03-11, 04-02A and 09-01A. QUIKRETE Mortar Mix datasheet, product 1102. All read on October 12, 2026. Metric results are converted from the imperial tables.
Actual use depends on bond pattern, brick coring, joint tooling and workmanship. For concrete itself, see the concrete slab calculator.
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