Eurorack Dimensions

One of the most important specifications for Eurorack is the case size, namely the height and width of the modules. The size of the modules originates from the 19-inch rack unit standard. The width is based on dividing 19 inches into 84 subunits, including the casing or rack ears. This results in a calculated size of 1 HP = 5.08 mm (1/5 inch). In practice, the width is made slightly smaller (by a few tenths of a millimetre) to allow for assembly tolerances.

To secure modules in the rack, the most common screw is M3×6, requiring a hole with a 3.2 mm diameter. It is common to use an oval-shaped hole, approximately double the width of its height, to allow for minor adjustments between modules. The horizontal distance between hole centres is always a multiple (N) of 1 HP (5.08 mm) or 7.5 mm from the next edge.

The standard faceplate height is three times the height of a standard rack unit (1U = 1.75 in = 44.45 mm, so 3U = 133.4 mm). As with the width, the final height is slightly reduced to account for mounting rail size, resulting in a panel height of 128.5 mm.

The second Eurorack format is 1U, which is one unit high. There are two 1U standards: Intellijel and Pulp Logic. The main difference is height—Pulp Logic 1U measures 43.18 mm, while Intellijel 1U measures 39.65 mm.

The PCB behind the front panel is typically about 17.5 mm shorter than the panel height, resulting in approximately 111 mm for a 3U PCB, d mm for Intellijel 1U, and 25.68 mm for Pulp Logic 1U. Smaller PCBs can also be used to save resources and reduce manufacturing costs.