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Cary Clark / FAQ / Build / dimensions

What are the dimensions of LEGO® brick?

From Robert M. Dye: !

A 2x2 brick is 5 plates wide, so the aspect ratio is 1 (stud-to-stud) to 2.5 (thickness of plates). Or, 1 (brick thickness) to 1.2 (stud-to-stud). Or, 1 (plate thickness) to 0.4 (stud-to-stud).

From Steve Bliss: !

The basic ratio is 2:5, for stud-spacing to plate-height -- which is why you see Technic models with beam-plate-plate-beam stacked up: this allows beams to be placed vertically, and connected to the other beams.

In LDU (LDraw units), the measurements are:

Brick height = 24
Plate height =  8
Stud pitch   = 20

I believe the LU (LEGO Unit) measurements are:

Brick height = 6
Plate height = 2
Stud pitch   = 5

From Robert Munafo: !

The actual dimension (rather than the ratios) can be determined by carefully measuring a properly constructed “wall” of bricks. Vertical dimensions are prone to error caused by sloppy stacking, but long horizontal walls constructed from two or more layers of overlapping bricks are not prone to such error. A wall of this type built from Technic beams made in the late 1990’s shows that the stud pitch distance is 7.986 millimeters, plus or minus 2 microns, when the parts are at 25 degrees centigrade (77 degrees Farenheit).

It is also worthwhile to note that LEGO bricks are always made a little smaller than this dimension would suggest. For example, the length of a 2x4 brick is a little less than 4 times 7.986 millimeters. The length is diminished slightly so that there will be a small gap when bricks are stacked next to each other. This gap allows for dust, marred surfaces and other imperfections. If the gap were not there the bricks would tend to push each other apart and the overall construction would be less strong.

Using the ratios above and converting to imperial measurements yields the following figures for all three dimensions:

Brick height 9.582 mm 0.37724 in Plate height 3.194 mm 0.12575 in Stud pitch 7.985 mm 0.31437 in

The following popular approximations are often used. Note that the Imperial approximations are each about 1 percent smaller than the corresponding S.I. (Metric) approximation:

S.I. Imperial Brick height 9.6 mm = 48/5 mm 0.375 in = 3/8 in Plate height 3.2 mm = 16/5 mm 0.125 in = 1/8 in Stud pitch 8.0 mm 0.3125 in = 5/16 in

From Robert Munafo: !

If you do the math you get:

  1 LDU = 0.3993 +/- 0.0001 millimeters
  1 millimeter = 2.5043 +/- 0.0006 LDU
  1 LDU = 0.015720 +/- 0.000004 inches
  1 inch = 63.611 +/- 0.016 LDU

From Jef Poskanzer: !

Approximate dimensions in millimeters:

 Spacing of stud centers:           8
 Diameter of studs:                 5
 Height of block:                   9.6
 Height of studs:                   1.7
 Thickness of brick walls:          1.5
 Outer diameter of cylinders
   (found on underside of bricks):  6.31
 Thickness of cylinder walls:       0.657

(height of brick)
(thickness of brick walls)
(height of studs)
(outer diameter of cylinders)
(thickness of cylinder walls)

=
=
=
=
=

(spacing of stud centers) * 6 / 5
((spacing of stud centers) - (diameter of studs)) / 2
(height of brick) / 3 - (thickness of brick walls)
sqrt(2) * (spacing of stud centers) - (diameter of studs)
((outer diameter of cylinders) - (diameter of studs)) / 2

From David Eaton: !

Here’s a conversion tool to convert between minifig or Technic scale to real-world units:
http://www.suave.net/~dave/cgi/scale.cgi

Primary content in this document is © Cary Clark. All other text, images, or trademarks in this document are the intellectual property of their respective owners.