How do I determine what number to input for VLAN ID?

How do I find out what number to input for the VLAN ID?

Pick one. A common convention is to use the third “set” of numbers in the subnet so, for example, should be 50, would be 51, etc.


Thank you for your reply Nick. This is helpful. May I ask for a simple explanation for the reason behind this? Also what could go wrong if I didn’t set a proper VLAN ID number? For example: and the VLAN ID is 70? What negative outcome could this have? Does the VLAN ID number really matter?

No it does not. You set it to what you want. Its just easier to associate a number in the subnet with the VLAN ID. I use the same method @Rick-DC mentioned above. Third octet in the subnet…


That’s not the issue. It’s exactly as @defcomllc suggested – convenience.


If you implement a policy that you always create VLAN ID using the 3rd octet in the subnet then you don’t have to go looking VLAN ID’s up when tagging VLAN at the device or switch port level. If you know your VOIP VLAN subnet is with a VLAN ID of 50… You just tag 50 to your switch ports and/or VOIP devices when needed. You know this very quickly by just looking at the 3rd octet in the subnet… Same applies to any other VLAN subnet you create.

But I cant imagine using some random VLAN ID like say 77 for because I sure as hell would never remember that or be able to get that out of looking at the subnet… I would always have to look that up in my Router or my notes… Its all about simplicity and standardization. I have enough to remember. Haha… Hope that helps…


Yes it helped. Thanks.

Another option is 10.22.22.x for VLAN 22 and 10.24.24.x for VLAN 24. Even more obvious.