Concrete Block (CMU) Sizes
Standard concrete masonry unit nominal vs actual dimensions and weights (medium weight).
| Nominal | Actual Height | Actual Width | Actual Length | Weight |
|---|---|---|---|---|
| 4x8x16 | 3.625 | 7.625 | 15.625 | 14 |
| 6x8x16 | 5.625 | 7.625 | 15.625 | 18 |
| 8x8x16 | 7.625 | 7.625 | 15.625 | 25 |
| 10x8x16 | 9.625 | 7.625 | 15.625 | 32 |
| 12x8x16 | 11.625 | 7.625 | 15.625 | 38 |
About this lookup
- What is the most common CMU size?
- 8x8x16 is the most common US concrete block size.
- Why is actual smaller than nominal?
- Mortar joints (typically 3/8") account for the difference.