A standard Lego brick is 9.6 millimeters high, measured without counting the stud on top.
That dimension is part of Lego’s modular geometry. A regular brick is three plates tall, and each plate measures 3.2 millimeters. This relationship lets builders substitute three stacked plates for one brick while keeping rows and walls aligned. The familiar 2×4 brick follows the same height standard as a 1×1 or 2×2 brick; its footprint changes, but its basic height does not.
The studs create a frequent source of confusion. A brick’s nominal stacking height is measured from its bottom to its top face, excluding the projecting stud. Once bricks are connected, the stud fits into the underside of the next piece, so it does not add another full stacking interval. The overall physical height of an isolated brick including its stud is therefore greater than 9.6 millimeters.
Width and length use a different convention: the stud pitch is nominally 8 millimeters, while the molded body is slightly smaller to allow pieces to grip and release. Duplo bricks are a separate, larger system and should not be used when answering this standard-brick question.