I'm about to buy (for the first time obviously) a bare rackable box to build a server.

As I understands things, standard rack size is 19" wide. But some boxes specs (Antec's one to be specific) says they are 17" wide... Is this a problem ?

4 Answers 4


It will most likely come with ears or rails to make it the right size to fit in the rack. If the device is indicated to be rack-mountable, it will come with the supplied hardware to make up the difference in width. (In my experience, at least)


When a vendor says 19" rack mountable what they actually mean is "19 inches on the center." What that means is that the distance between the center points of the mounting holes on either side of the rail is 19 inches, not that 19 inch wide equipment can fit inside. The actual width available for equipment is a fair bit smaller than that.

Once you install the ears or rails on the device, and measure the distance between the mounting points, you should get something very close to 19 inches.

  • 4
    +1 It's 19" center-to-center on the mounting holes, minus the rails, servers tend to be around 17" wide.
    – Chris S
    Commented Jan 10, 2011 at 16:16
  • It gets really exciting when racking cheap rail kits on aluminum 2-posters where someone shimmed a bit much and you really only have about 18.8".
    – Scott Pack
    Commented Jan 10, 2011 at 16:32

You can rack things that are smaller than the exact internal width of the rack by using the ears that the vendor should have supplied to you, if they're saying saying that it's a rackmount piece of gear.


It's a 'box that fits in a 19" rack', not a '19" box that fits in a rack'.

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