Nominal, specified, actual — three different numbers
A brick has up to three sets of dimensions and they are not interchangeable. Nearly every wrong brick count traces back to mixing them up.
- Nominal — the brick plus its intended mortar joint, rounded to a 4 in. or 8 in. module. This is what plans are drawn to. Only modular brick has one.
- Specified — the brick as manufactured, no mortar. This is what belongs on a purchase order, and BIA recommends specifying by these rather than by name.
- Actual — what arrives, within the tolerances of ASTM C216 for facing brick or C652 for hollow brick. Clay shrinks in the kiln and not perfectly evenly.
So a modular brick is 8 in. long and also 7⅝ in. long, depending on which number you mean. The ⅜ in. gap is the mortar joint, designed in. Lay modular brick with ⅜ in. joints and four of them plus joints span exactly 32 in. — that is the whole point of a modular system, and it is why openings, corners and returns work out without cutting.
Modular brick sizes
These have nominal dimensions, so the joint is already accounted for. Specified sizes are shown for the two standard joint widths.
| Size | Nominal W×H×L | Specified @ ⅜ | Coursing | Per ft² | Per 100 ft² |
|---|---|---|---|---|---|
| Modular | 4 × 2⅔ × 8 | 3⅝ × 2¼ × 7⅝ | 3C = 8 in. | 6.75 | 675 |
| Engineer Modular | 4 × 3⅕ × 8 | 3⅝ × 2¹³⁄₁₆ × 7⅝ | 5C = 16 in. | 5.63 | 563 |
| Closure Modular | 4 × 4 × 8 | 3⅝ × 3⅝ × 7⅝ | 1C = 4 in. | 4.50 | 450 |
| Roman | 4 × 2 × 12 | 3⅝ × 1⅝ × 11⅝ | 2C = 4 in. | 6.00 | 600 |
| Norman | 4 × 2⅔ × 12 | 3⅝ × 2¼ × 11⅝ | 3C = 8 in. | 4.50 | 450 |
| Utility | 4 × 4 × 12 | 3⅝ × 3⅝ × 11⅝ | 1C = 4 in. | 3.00 | 300 |
| Meridian | 4 × 4 × 16 | 3⅝ × 3⅝ × 15⅝ | 1C = 4 in. | 2.25 | 225 |
The coursing column is the one masons care about. “3C = 8 in.” means three courses rise exactly 8 in., so modular brick lands on an 8 in. module every third course — which is how brickwork aligns with window heads, sills and floor levels without a cut course. Closure modular and utility give you 1C = 4 in., the simplest case of all.
Non-modular brick sizes
These have no nominal dimensions at all. The joint is not included in the published size — you add it. BIA gives some of these as ranges because they genuinely vary by plant.
| Size | Specified W×H×L | Per ft² | Per 100 ft² |
|---|---|---|---|
| Standard | 3⅝ × 2¼ × 8 | 6.55 | 655 |
| Queen | 2¾ × 2¾ × 8 | 5.50 | 550 |
| King | 2¾ × 2¾ × 9¾ | 4.55 | 455 |
BIA gives a range: width 2¾–3 in., height 2¾ in., length 7⅝–8 in. The published count of 550 per 100 sq ft corresponds to the 8 in. length. BIA gives a range: width 2¾–3 in., height 2⅝–2¾ in., length 9⅝–9¾ in. The published count of 455 per 100 sq ft corresponds to the 2¾ × 9¾ combination.
“Standard” and “modular” are different bricks
This trips up homeowners and estimators equally. Ask what the standard brick size is and you will be told 8 inches long. Both of these are true:
| Modular | Standard | |
|---|---|---|
| Nominal | 4 × 2⅔ × 8 | none |
| Specified @ ⅜ in. | 3⅝ × 2¼ × 7⅝ | 3⅝ × 2¼ × 8 |
| Space each occupies | 2⅔ × 8 in. | 2⅝ × 8⅜ in. |
| Per ft² | 6.75 | 6.55 |
| Lands on a module | Yes — 3C = 8 in. | No |
Modular is 8 in. long nominal; standard is 8 in. long specified. A standard brick is physically longer than a modular one, occupies more wall once its joint is added, and yet works out to slightly fewer per square foot — 6.55 against 6.75 — because it is also shorter in height. The two sizes are close enough to look identical in a wall and far enough apart to ruin a layout.
A trap in BIA's own coverage table
BIA publishes one brick count per size. For modular brick that is complete, because nominal dimensions absorb the joint — the count holds whether you lay ⅜ in. or ½ in. joints, since the brick itself shrinks to compensate.
For non-modular brick it is not complete, and the table does not say so. Those published counts reproduce the geometry at a ⅜ in. joint only. Lay them with ½ in. joints and each brick occupies more wall, so you need fewer:
| Size | BIA published | True @ ½ in. | Over-order |
|---|---|---|---|
| Standard | 6.55/ft² | 6.16/ft² | +6.3% |
| Queen | 5.50/ft² | 5.21/ft² | +5.5% |
| King | 4.55/ft² | 4.32/ft² | +5.3% |
It is not an error in the table — it is an unstated assumption, and the modular sizes it sits alongside genuinely do not have it. Our brick calculator uses the published figure where it matches the geometry and the geometry where it does not, and tells you which one it used.
Mortar per thousand, by size
Mortar scales with joint area, not brick count, so larger units need more mortar per thousand even though they need fewer per wall. These are net figures — BIA adds 15–25% waste on top.
| Size | ft³ / 1000 @ ⅜ | ft³ / 1000 @ ½ | ft³ / 100 ft² @ ⅜ |
|---|---|---|---|
| Modular | 8.1 | 10.3 | 5.5 |
| Engineer Modular | 8.5 | 10.8 | 4.8 |
| Closure Modular | 9.1 | 11.6 | 4.1 |
| Roman | 10.7 | 13.7 | 6.4 |
| Norman | 11.2 | 14.3 | 5.1 |
| Utility | 12.3 | 15.7 | 3.7 |
| Meridian | 15.4 | 19.7 | 3.5 |
| Standard | 14.5 | 17.8 | 9.5 |
| Queen | 12.2 | 13.5 | 6.7 |
| King | 14.2 | 16 | 6.5 |
Read the last two columns together and the trade-off is clear. Going from a ⅜ to a ½ in. joint raises mortar by roughly a quarter across every size. Going from modular to utility cuts the brick count by more than half but raises mortar per thousand from 8.1 to 12.3 ft³ — bigger bricks, bigger joints around each one.
Courses to height
How many courses reach 8 ft, at a ⅜ in. joint. Whole numbers mean the wall lands clean; a fraction means a cut course or an adjusted joint somewhere.
| Size | Course height | Courses in 8 ft |
|---|---|---|
| Modular | 2.67 in | 36.00 ✓ |
| Engineer Modular | 3.20 in | 30.00 ✓ |
| Closure Modular | 4.00 in | 24.00 ✓ |
| Roman | 2.00 in | 48.00 ✓ |
| Norman | 2.67 in | 36.00 ✓ |
| Utility | 4.00 in | 24.00 ✓ |
| Meridian | 4.00 in | 24.00 ✓ |
| Standard | 2.63 in | 36.57 |
| Queen | 3.13 in | 30.72 |
| King | 3.13 in | 30.72 |
Every modular size lands exactly on 8 ft. None of the non-modular sizes do, which is the practical cost of choosing them — not a reason to avoid them, but a reason to expect the mason to adjust joints or cut a course, and to ask how before the wall goes up.
Ordering, in one line
BIA's own advice is worth repeating exactly: specify brick using the stretcher position with width first, then height, then length, using specified dimensions. So a modular brick is ordered as 3⅝ × 2¼ × 7⅝ in., not as “modular” and not as 4 × 2⅔ × 8. Names travel badly between plants; dimensions do not.
Once you have the size, the brick calculator turns a wall into a brick count and a mortar volume, with bond-pattern corrections and BIA's separate brick and mortar waste allowances applied in the order BIA specifies.