Brick and block calculator: bricks, concrete blocks and mortar
Work out how many bricks or concrete blocks a wall needs. Enter the wall's length and height and any openings, pick the unit, and get the units to order with waste, the mortar bags and the material cost.
Brick & block: units, mortar & cost
Enter the wall and the unit, and get the net wall area, the bricks or concrete blocks to order with waste, the mortar bags and the material cost.
The wall
Result
Net area = length × height − openings. Units = net area × units per sq ft (with 3/8 in joints), then × (1 + waste). Mortar = units ÷ 100 × bags per 100 units — a planning figure; joint size, unit type and the mix change it, so confirm with the mortar maker's yield table. Single wythe; double it for a two-wythe wall.
How to use it
- Measure the wall's length and height and add up the openings to deduct.
- Pick the unit: modular, queen or utility brick, or 8 or 12 in concrete block.
- Set waste — about 5% for brick, more where there are many cuts.
- Check the mortar rate against your supplier's yield and enter the unit price.
A worked example
Units per square foot
| Unit | Nominal size | Per sq ft of wall |
|---|---|---|
| Modular brick | 4 × 2⅔ × 8 in | 6.75 |
| Queen brick | ≈3 × 2¾ × 8⅝ in | ≈5.8 |
| Utility brick | 4 × 4 × 12 in | 3.0 |
| Concrete block (CMU) | 8 × 8 × 16 in (or 12 × 8 × 16) | 1.125 |
Nominal sizes include a 3/8 in mortar joint. A wall face of 1 sq ft holds 144 sq in; an 8 × 16 in block face is 128 sq in, so 144 ÷ 128 = 1.125 blocks. Two-wythe walls double the units.
What the calculator leaves out
Sand (if you mix your own mortar), wall ties, horizontal joint reinforcement, flashing and weeps, grout and rebar for reinforced block cores, lintels and scaffolding. Those belong in the estimate on their own lines, each with its own cost code — the cost codes guide covers structuring them.
Questions
How many bricks are in a square foot?
About 6.75 modular bricks per square foot of wall face with 3/8 in mortar joints, around 5.8 queen bricks and 3 utility bricks. Multiply by the net wall area and add waste.
How many concrete blocks do I need?
1.125 standard 8×8×16 in blocks per square foot of wall. A 320 sq ft wall takes 360 blocks before waste.
How much mortar do I need for 1,000 bricks?
A common rule of thumb is about seven bags of masonry cement per 1,000 modular bricks with sand, but joint size, the unit and the mix change it — use the mortar maker's yield table.
How much waste should I allow for brick?
Around 5% for straightforward walls; more for many corners, openings and cuts, or for units that chip in handling.
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