ISO 7736

International standard ISO 7736 defines a standard size for car audio head units and enclosures. The standard was originally established by the German standards body Deutsches Institut für Normung as DIN 75490, and is therefore commonly referred to as the "DIN car radio size". It was adopted as an international standard in 1984.

Head units generally come in either single DIN (180 x 50 mm panel) or double DIN (180 x 100 mm panel) size. The depth is not standardized; as a result, some cars such as the Opel Manta / Ascona have the correct sized front aperture but will accommodate few DIN sized radios other than the original due to the shallow depth; this despite the vehicle being manufactured as late as 1988. The US standard for a DIN radio is 7" x 2" (although the actual 180 mm width converts to something like 7-3/32" so most people use 7-1/8" to allow for clearance) and the Double DIN sized radio is a 7" x 4". Some radios in Japanese Kei cars do not conform to the DIN standard however.

Uniden Bearcat BCT-15

Blaupunkt Hamburg MP57

Single DIN spacer pocket

Rack braces and screw mounts exposed for single DIN installation

Double DIN combining a single DIN head unit and a single DIN compact disc player

Cobra 18 WX ST II CB mobile radio

Uniden BCT-15 installed into double DIN using a spacer pocket

Sony MEX-BT2500 installed into single DIN

Sony MEX-BT2500 head unit installed in upper single DIN, spacer pocket and Uniden BCT-15 radio scanner installed in lower double DIN

1.5 DIN OEM stereo with optional DIN sized CD player

Single DIN head unit

Alpine double DIN head unit

Pioneer FH-P80BT double DIN head unit, installed in a 1995 Volvo 960.

Volvo SC-800 double DIN head unit, installed in a 1995 Volvo 960.

For removing the unit, a pair of U-shaped devices are often used. The devices are inserted in the two pairs of holes, at either end of the stereo fascia, the action releasing the unit from the mounting and providing a pair of handles to pull the unit free. These tools vary from manufacturer to manufacturer. Becker uses a pair of key-shaped removal tools, with one hole each. Often a set of thin screwdrivers will work just as well.

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