Brick Calculator

How to use the Brick Calculator

Measure the wall face and deduct the doors and windows. Pick the brick size, modular is the common US brick and the default here, and set the number of wythes: one for a brick veneer over a framed wall, two for a solid brick wall.

For paving, bricks are laid flat, so the coverage comes from the bed face rather than the side. Enter the actual brick dimensions and the joint width, or set the joint to zero for a tight sand-set patio.

Brick and Mortar Cost prices both materials together, which is the honest way to compare bricks. A utility brick costs more each but you lay far fewer of them, and the mortar bill moves with the joint count rather than the wall area.

Brick formula

Everything comes from the nominal face, the brick plus one mortar joint:

• bricks per sq ft = 144 ÷ (nominal length × nominal height)
• bricks = wall area × bricks per sq ft × wythes
• Paving: bricks per sq ft = 144 ÷ ((length + joint) × (width + joint))

Check it yourself: a modular brick face is 8 × 2⅔ = 21.33 square inches, and 144 ÷ 21.33 = 6.75. Every figure in that table is 144 divided by the nominal face area.

Mortar, using premixed bags: roughly 30 modular bricks per 80 lb bag.

Worked example

A 20 ft × 8 ft single-wythe modular brick wall, no openings, 5% waste:

• Area: 20 × 8 = 160 sq ft
• Bricks: 160 × 6.75 = 1,080, plus 5% = 1,134 bricks
• Mortar: 1,134 ÷ 30 = 37.8, so 38 bags of 80 lb premixed

A 16 ft × 12 ft patio in 8 × 4 in pavers with a ⅜ in joint: each brick occupies 8.375 × 4.375 = 36.64 sq in, so 3.93 per sq ft, 831 bricks for 192 sq ft with 10% waste.

What the result means

The nominal size is the one that matters. A modular brick actually measures 7⅝ × 2¼ in, but you lay it with a ⅜ in joint, so it occupies 8 × 2⅔ in of wall. Calculating from the actual brick size instead of the nominal one over-orders by about eight percent.

Two wythes doubles the brick count but not the wall area. A solid two-wythe wall also needs header courses or wall ties, which is a structural question rather than a quantity one.

Mortar bag coverage is the softest number here. Thirty bricks per 80 lb bag is a working figure for premixed mortar at a standard joint; joint thickness, brick absorbency and how much you drop all move it. The mortar calculator has the site-mixed portland-and-sand version, which works out very differently.

Common mistakes

• Using the actual brick size instead of the nominal. The joint is part of the module. This is the most common brick-quantity error and it runs about eight percent.
• Forgetting the second wythe. A solid brick wall is two bricks thick, so it takes twice the bricks the face area suggests.
• Ordering exactly. Bricks arrive with breakage, corners need cutting, and a later batch will be a visibly different shade. Five percent minimum, ten for patterned work.
• Assuming paving bricks lay like wall bricks. Flat on the bed face they cover far more area per brick, and the count drops accordingly.
• Buying mortar to a brick count without checking the product. Premixed mortar and portland-plus-sand give wildly different bag counts for the same wall.

Frequently asked questions