Mix right.
Bags of mortar mix for brick, block, and stone walls. Accounts for joint width, brick size, and mortar type so you order the right amount.
How we calculated this
Mortar volume per brick is calculated from the joint geometry: bed joint (length × width × depth) plus head joint (height × width × depth) for each brick face. Standard bricks with 3/8-inch joints use approximately 6.5 cubic inches of mortar per brick. Wider joints increase this proportionally.
An 80-lb bag of pre-mixed mortar yields approximately 450 cubic inches of mixed mortar, enough for about 30-40 standard bricks at 3/8-inch joints. Coverage varies with joint width: wider joints use more mortar per brick and reduce bags-per-1000 count.
A 10% waste factor covers mortar that drops during tooling, mortar that sets before use, and extra material needed for cap rows and tooling joints. Experienced masons waste less; first-time DIYers may waste 15-20%.
Mortar type (S, N, M) does not change the volume calculation. All three types yield the same volume per bag. The type affects bond strength, compressive strength, and weather resistance. Type S is the default for exterior residential masonry.
Concrete block (CMU) uses significantly more mortar per unit than brick because the face shells and web create longer joint lines per block. A standard 8×8×16 block uses approximately 22.5 cubic inches of mortar at 3/8-inch joints.
Mortar is not grout, and the difference matters
People search for "mortar calculator" and land on grout calculators. The two products are not interchangeable. Mortar bonds bricks, blocks, or stones together. It contains Portland cement, lime, and sand in a ratio that gives it body and adhesion. Grout fills the narrow joints between tiles. It contains cement and fine aggregate with no lime, formulated to flow into thin gaps. Using grout between bricks creates a weak bond that crumbles within a year. Using mortar between tiles leaves a rough, oversized joint that looks terrible and traps dirt. The calculator above is specifically for mortar — bed joints and head joints in masonry walls.
If your project involves tile, use the grout calculator instead. If it involves bricks, blocks, or stone, you are in the right place.
How we calculated these numbers▾
Mortar volume per brick calculated from joint geometry: (bed joint length × width × depth) + (head joint height × width × depth) per brick face. Coverage per 80-lb bag approximately 450 cubic inches of mixed mortar (BIA Technical Note 8). Waste factor of 10% applied for drops, tooling, and cleanup. Mortar type specifications per ASTM C270 (proportion specification).
Choosing the right mortar type
The type designation is not a quality grade. Type M is not "better" than Type S. Each is formulated for a specific application. Type S has the best balance of bond strength and flexibility, making it the default for exterior walls, chimneys, and any structural masonry above grade. Type N has lower compressive strength but higher workability, which makes it easier to tool and better for interior accent walls and veneer where structural load is not a concern. Type M has the highest compressive strength (2,500 psi) but the lowest bond strength, which makes it the wrong choice for walls exposed to wind load but the right choice for retaining walls and foundations where compressive force dominates.
How many bags for your wall
Composite illustration based on typical project dimensions, regional contractor pricing, and 2026 material costs. Not a specific real project.
Mixing mortar correctly
The consistency you want is often described as "peanut butter" — thick enough to hold its shape on the trowel when you flip it upside down, but wet enough to spread easily into a bed joint. Too dry and the mortar will not bond to the brick surface. Too wet and it squeezes out of the joint and runs down the wall face, staining the brick. Start with about 5 quarts of water per 80-lb bag and adjust by small amounts. The correct consistency depends on temperature and humidity. Hot dry days require slightly more water. Cold damp days require less.
Pre-mixed bags | Site-mixed | |
|---|---|---|
| Cost per bag equiv. | $7–10 | $4–6 |
| Consistency | Reliable batch to batch | Varies with proportioning |
| Best for | Under 500 bricks, DIY | Large jobs, experienced masons |
| Mixing | Add water only | Proportion cement + lime + sand |
| Shelf life | 12 months sealed | Cement: 3 months, sand: indefinite |
For residential projects, pre-mixed bags are the standard. The cost premium over site-mixed is small and the consistency is guaranteed.
How mortar quantity connects to brick quantity
The brick calculator estimates brick count and includes a mortar line item. This mortar calculator gives you a more detailed breakdown with mortar type selection and mixing guidance. For projects that need both tools, start with the brick calculator for the brick count, then use this calculator to verify the mortar quantity with your specific joint width and mortar type.
For the concrete footings under a brick wall, the concrete calculator handles footing volume. For reinforcement in the footing or within a block wall (rebar in filled cores), the rebar calculator estimates bar count and total length.
Sources
- Brick Industry Association — Technical Note 8 (Mortar for Brick Masonry)
- ASTM C270 — Standard Specification for Mortar for Unit Masonry
- Portland Cement Association — Mortar Information
Frequently asked
How many bags of mortar do I need per 1,000 bricks?
With standard 3/8-inch joints, about 7 bags of 80-lb Type S mortar per 1,000 standard bricks. Wider 1/2-inch joints increase this to about 9 bags. The calculator accounts for brick size and joint width automatically.
What is the difference between Type S, Type N, and Type M mortar?
Type S is the default for exterior walls and structural applications — it has the best bond strength and weather resistance. Type N is for interior and above-grade non-structural work. Type M has the highest compressive strength and is used below grade (retaining walls, foundations).
Can I use mortar instead of grout?
No. Mortar bonds bricks or blocks together and has sand for body. Grout fills joints between tiles and is much thinner. They are different products with different formulations. Use the grout calculator for tile projects.
How long does a bag of mortar last once opened?
Unopened bags last 12 months in dry storage. Once opened, use within 1-2 months. Mixed mortar must be used within 90 minutes to 2 hours before it begins to set. Do not add water to mortar that has started to stiffen.
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