How much mortar do I need?
Count the bricks or blocks, including waste, and divide by how many one bag lays. That yield depends on the bag. A 70 lb bag of masonry cement gets mixed with sand on site and makes a lot of mortar. An 80 lb bag of premixed mortar mix already has the sand in it and makes much less.
Bags = bricks or blocks ÷ units per bag. Sand = bags of masonry cement × about 3 cu ft.
For 1,000 modular bricks at 125 bricks per bag of masonry cement, you need 8 bags. Mix each with about 3 cu ft of sand: 24 cu ft, or about 1.2 tons. For 189 standard blocks at 30 blocks per bag, you need 7 bags and 21 cu ft of sand. That matches the concrete block calculator.
If you don't have a count, switch to "Wall size" and enter each wall. The calculator converts it at 6.86 modular bricks or 1.125 blocks per square foot, adds your waste, then works out the mortar.
Mortar yield per bag
These are common rules of thumb, not fixed numbers. Joint size, bond pattern, brand and how much mortar gets dropped all change them. Read the bag and adjust the field.
| Laying | Masonry cement, 70 lb + sand | Premixed mortar mix, 80 lb |
|---|---|---|
| Modular brick, 3/8 in joints | about 125 bricks per bag | typically 30 to 40 bricks |
| 8 × 8 × 16 in block | typically 28 to 35 blocks | about 12 blocks |
| Stone veneer, scratch coat plus setting bed | roughly 20 sq ft | roughly 5 to 8 sq ft |
Masonry cement is typically mixed at 1 part cement to 2-1/4 to 3 parts sand by volume. A bag is about 1 cu ft, so each bag takes about 3 cu ft of mason sand. The calculator sells sand by the half ton, at about 100 lb per cubic foot.
Type N or Type S mortar?
ASTM C270 sets minimum compressive strengths for each mortar type: 750 psi for Type N, 1,800 psi for Type S and 2,500 psi for Type M. Type N is the usual choice for above-grade walls and brick veneer. Type S is used below grade, for foundations and retaining walls, and where the wall takes higher lateral loads. Stronger isn't always better: a mortar that's harder than the brick can lead to cracked units. Use what your plans, the brick maker or local code specify. The type doesn't change the bag count much.
Brick mortar calculator
Use the default of 125 modular bricks per bag of masonry cement, or about 35 per bag of premix. Queen, king and utility bricks need a different amount of mortar per brick. The brick calculator adjusts the yield for the size and joint and counts the bricks too.
Mortar calculator for block
Standard 8 × 8 × 16 in block typically takes one bag of masonry cement for every 28 to 35 blocks, mixed with sand. The calculator uses 30. With premixed mortar mix, plan on about 12 blocks per bag. That makes premix practical for small repairs and short walls, while masonry cement and bulk sand cost less on a full wall.
Stone veneer mortar
Thin stone veneer is set on a scratch coat, typically about 1/2 in thick, with mortar buttered on the back of each stone. Coverage depends on the stone's thickness and how wide you run the joints, so the figures here are a rough starting point. Follow the stone maker's install guide. Many specify a Type S or a mortar made for stone veneer.
Pricing a masonry job
Mortar and sand are usually separate lines on a masonry quote, priced at cost plus markup. Bulk sand often has a delivery charge too. Price the full job, bricks or blocks and labor included, from the brick or block calculator in contractor mode, then send it as an estimate.
Questions
How many bricks does a bag of mortar lay?
About 125 modular bricks per 70 lb bag of masonry cement mixed with sand, as a rule of thumb. An 80 lb bag of premixed mortar mix typically lays 30 to 40. Joint size and waste change both.
How many blocks can you lay with one bag of mortar?
Typically 28 to 35 standard 8 x 8 x 16 in blocks per bag of masonry cement mixed with sand, and about 12 per 80 lb bag of premixed mortar mix.
How much sand do I mix with a bag of masonry cement?
Typically 2-1/4 to 3 parts sand to 1 part masonry cement by volume, so about 3 cubic feet of mason sand per bag.
What is the difference between Type N and Type S mortar?
Type S is stronger, with a minimum of 1,800 psi under ASTM C270, against 750 psi for Type N. Type N is typical for above-grade walls and veneer. Type S is used below grade and for retaining and structural walls.