US utility brick
295.3 × 92.1 × 92.1 mm
11 5/8 × 3 5/8 × 3 5/8 in · format 304.8 × 101.6 mm · 33 per m² · North America
About this unit
A nominal 12 × 4 × 4 inch unit, used where the scale of a building suits a larger face. Three utility courses rise 12 inches.
The size that matters is the format
A brick is never laid on its own. Add one 9.5 mm joint and the working unit becomes 304.8 × 101.6 mm, and every dimension in the wall is a multiple of that rather than of the brick.
| Actual size | 295.3 × 92.1 × 92.1 mm |
| Mortar joint | 9.5 mm |
| Format size | 304.8 × 101.6 mm |
| Per square metre, single skin | 32.29 — order 34 with 5% waste |
| Courses per metre of height | 9.84 |
| Units per metre of length | 3.28 |
Setting out
Ten courses rise 1016 mm and ten units run 3048 mm. Openings, sills and damp courses are placed on those multiples wherever possible, because a wall that has to be cut to reach a dimension costs labour and shows.
Other North America units
| Unit | Actual | Format | Per m² |
|---|---|---|---|
| US modular brick | 194 × 57 × 92 mm | 203.2 × 66.7 | 73.8 |
| US queen brick | 194 × 70 × 79 mm | 203.2 × 79.4 | 62.0 |
| US king brick | 244 × 70 × 76 mm | 254.0 × 79.4 | 49.6 |
| US concrete block | 397 × 194 × 194 mm | 406.4 × 203.2 | 12.1 |
Frequently asked questions
What size is a us utility brick?
295.3 × 92.1 × 92.1 mm (11 5/8 × 3 5/8 × 3 5/8 in). Add the 9.5 mm joint and the working size — the format — is 304.8 × 101.6 mm.
How many bricks per square metre?
32.3 for a single skin — 33 in practice, before allowing for breakage. That comes straight from the format: 1,000,000 mm² ÷ (304.8 × 101.6) = 32.29.
How many courses per metre of height?
9.84 courses, at 101.6 mm each. Setting out from a fixed course height is why a window head or a damp course lands where it does rather than where a drawing might prefer.
Why does the joint matter so much?
Because the brick on its own is never the unit of construction. Masonry is set out on the format size — one unit plus one joint — and every dimension in a wall is a multiple of it. A 92.1 mm brick with a 9.5 mm bed rises 101.6 mm per course, and that 101.6 is the number the wall is actually built from.