Brick Calculator
How many bricks and bags of mortar a wall requires is worked out here, based on wall size, brick dimensions, and mortar joint thickness. This brick calculator can also be used as a brick wall calculator for veneer siding or a masonry cost estimator once a per-brick price is known.
From a wall’s dimensions to an order quantity
A tiling problem, not a volume problem, is what brick counting really is — the question being answered is how many brick-plus-mortar-joint rectangles are needed to cover the wall’s face. Because of this, the joint size carries just as much weight as the brick’s physical dimensions: if it’s left out, coverage gets overstated, since real space is taken up by mortar between every course and every brick in practice.
An effective brick size is built by this brick and mortar calculator — actual dimensions plus one joint on each side — which is then converted into bricks per square foot, multiplied by the wall’s net area (gross area minus window and door openings), and combined with a waste allowance for cuts and breakage. Mortar bags are estimated from there using a coverage figure that can be adjusted to match the product on hand.
Because a single-wythe veneer wall is assumed, the brick count should be roughly doubled for a structural double-wythe wall, and the actual mortar bag’s coverage rating should be checked rather than relied on as a rule of thumb. Standard Modular is the most common brick size used across the US, though Queen, King, and Utility sizes are also covered by the presets above.
How brick quantities are calculated
How many brick-plus-joint units tile across the wall’s face is what determines the brick count — not the wall’s volume.
Effective brick size
Its actual size plus one mortar joint is “occupied” by each brick: Effective = (Length + Joint) × (Height + Joint).
Bricks per square foot
144 ÷ (Effective Length × Effective Height) — square inches are converted to a square foot by the 144.
Total bricks
Net Wall Area × Bricks per Sq Ft × (1 + Waste %), rounded up to a whole brick.
Mortar bags
Total Bricks ÷ Bricks Laid per Bag, rounded up — this coverage figure varies by mortar type and joint size, so it’s worth checking your bag.
Common US brick sizes
Standard face dimensions are listed below for the brick types most often used in US residential masonry.
| Type | Length | Face height |
|---|---|---|
| Standard Modular | 8″ | 2 1/4″ |
| Queen | 7 5/8″ | 2 3/4″ |
| King | 9 5/8″ | 2 3/4″ |
| Utility | 11 5/8″ | 3 5/8″ |
Step-by-step brick calculator examples
Three scenarios are converted end to end below, using the same formulas this brick calculator applies.
A straightforward veneer wall
“A 20 ft × 8 ft wall, no openings, is being built with standard modular brick and a 3/8-inch joint, with 10% waste allowed — how many bricks are needed?”
Inputs
- Net area: 20 × 8 = 160 sq ft
- Effective brick: (8+0.375) × (2.25+0.375) = 21.98 in²
- Bricks/sq ft: 144 ÷ 21.98 ≈ 6.55
Result
- Raw bricks: 160 × 6.55 ≈ 1,048
- With 10% waste: 1,048 × 1.10 ≈ 1,153 bricks
- Mortar bags (30 bricks/bag): ceil(1,153 ÷ 30) = 39 bags
A wall with window and door openings
“A 20 ft × 8 ft wall has 24 sq ft of openings, and the same standard modular brick is being used — how much does subtracting the openings change the count?”
Inputs
- Gross area: 20 × 8 = 160 sq ft
- Net area: 160 − 24 = 136 sq ft
- Bricks/sq ft: ≈ 6.55 (same brick/joint)
Result
- Raw bricks: 136 × 6.55 ≈ 891
- With 10% waste: 891 × 1.10 ≈ 980 bricks
- About 173 fewer bricks are needed than in the no-openings version — though a higher waste allowance is worth considering, since cuts around openings add extra waste in practice
Switching to a larger brick size
“The same 160 sq ft wall is being built with King size brick (9.625″ × 2.75″) instead of standard modular — how many fewer bricks does that require?”
Inputs
- Effective brick: (9.625+0.375) × (2.75+0.375) = 31.2 in²
- Bricks/sq ft: 144 ÷ 31.2 ≈ 4.62
- Net area: 160 sq ft
Result
- Raw bricks: 160 × 4.62 ≈ 739
- With 10% waste: 739 × 1.10 ≈ 813 bricks
- About 340 fewer bricks are required than with standard modular for the same wall — fewer units need to be laid when a larger brick is used
Where brick estimates go wrong
Forgetting the joint when sizing the brick
How many bricks fit per square foot gets overstated when only the brick’s physical dimensions are entered and the mortar joint is skipped — the joint has to be added to both length and height first.
Assuming this covers a double-wythe wall
Only a single layer of brick across the wall face is calculated here — a structural double-wythe wall needs roughly double the brick count plus a separate allowance for ties or a collar joint.
Using a generic waste percentage regardless of wall complexity
A simple straight run is well served by 10%, but meaningfully more offcuts are generated by walls with many corners, openings, or a running-bond pattern that needs half-bricks at the ends — the allowance should be pushed higher for those.
Trusting a generic mortar coverage number
“Bricks per bag” varies by mortar product, brick size, and joint thickness — the coverage printed on the actual mortar bag being used should always be checked rather than relied on as a rule of thumb.
Not subtracting openings before estimating
The brick count is inflated when window and door areas are left in the gross wall size — they should be subtracted for net area, though slightly more waste than the straight math implies should be expected due to cutting around the openings.
Brick calculator: common questions
Does this account for double-wythe (two brick thick) walls?+
Why does the mortar joint size matter so much?+
How much waste should I plan for?+
Should I subtract windows and doors from the wall area?+
How accurate is the mortar bag estimate?+
Formula references
Every figure produced by this brick calculator is derived from the published masonry standards listed below, rather than from an internally invented convention.