How to calculate bricks and blocks
Masonry is estimated by wall area. Find the area, then multiply by how many units cover a square foot (mortar joints included):
Units = wall area (sq ft) × units per sq ft × (1 + waste)
Measure the wall's length × height, subtract big openings like doors and windows, and add 5–10% for breakage and cut units. The number of units per square foot depends on what you're laying:
| Unit | Nominal face (with joint) | Per sq ft |
|---|---|---|
| Modular brick | 8 × 2⅔ in | ~6.75 (about 7) |
| Concrete block (CMU) | 16 × 8 in | ~1.125 (about 1⅛) |
Don't forget the mortar
Mortar use varies with joint thickness and your technique, but a useful rule of thumb is about one 80-lb bag of mortar mix per 30 modular bricks, or per 12 standard blocks. If you mix your own with masonry cement and sand instead of a premixed bag, plan on sand too. Buy a little extra — running out mid-course is a headache.
Brick sizes and types
"Brick" comes in several sizes, and the bigger the unit the fewer you need per square foot:
| Brick | Nominal face | Per sq ft |
|---|---|---|
| Modular (most common) | 8 × 2⅔ in | ~6.9 |
| Standard | 8 × 2¼ in | ~7 |
| Queen | 8 × 2¾ in | ~6 |
| Utility | 12 × 4 in | ~3 |
Also note the use: face brick for visible walls, paver brick (laid flat) for patios and walkways, and engineering brick where strength and low water absorption matter.
Which mortar type?
Mortar is graded by strength — pick the type to match the job (the letters come from the word "MaSoN wOrK"):
- Type N. General-purpose, above-grade exterior and interior walls — the usual DIY choice.
- Type S. Higher strength and bond for exterior at or below grade, and areas with wind or seismic load.
- Type M. The strongest, for foundations, retaining walls, and heavy loads.
- Type O. Low strength, for interior non-load-bearing work and repointing soft historic brick.
How much do bricks cost?
Common face brick runs roughly $0.40–$0.90 each, with standard concrete block about $1.50–$3. The mortar, sand, and any wall ties and reinforcement add to the material total, and laying brick is labor-intensive — masonry is one of the trades where labor often outweighs material.
Good to know
- This is a single-wythe wall. A wall that's two bricks thick (a double wythe) needs roughly twice the brick — run the numbers for each layer.
- Subtract real openings. Large doors and windows remove a meaningful number of units, so enter their combined area.
- Structural walls need more than a count. Load-bearing or retaining walls require proper footings, reinforcement, and often a permit — check local codes or a pro.