How do I know if my motherboard will fit with the usb 3.0 or 2.0?

[Justinplayz]

Ok so I'm building a computer and I don't know if the motherboard will fit right because I have 2x usb 3.0 and 4x usb 2.0 and I don't know if it'll fit into my case.

 

[ThatVietGuy]

The number of USB ports is irrelevant. This answer depends on the specific case and the specific motherboard.

If you're talking about the panel in the rear of the motherboard (that has USB, ethernet, etc.) that panel is a standard size and will fit the case you choose as long as the case supports the motherboard (i.e. you pair an ATX motherboard with a case that supports ATX).