MAC address contains 12 characters, with digits from 0 to 9, and letters from A to F. The letters may be either upper or lower case. Sometimes each pair of characters is separated by a colon, dash or a space. Sometimes there is no space at all.

For an external wireless card, check the card to see if the MAC address is recorded on a label. If your computer has an internal wireless card, you'll have to use the operating system to find the MAC address.

• Click on the Start Menu, then select the Run item.
• Type cmd in the text field.
• A terminal window will appear on the screen. Type ipconfig /all and return.
• There will be a block of information for each adapter on your computer. Look in the description field for wireless. The Physical Address for that block is your wireless MAC address.
  

• Click on the Apple Menu, and choose the Location menu item.
• Click on Network Preferences.
• Click on the Show menu and choose the AirPort item. The AirPort ID is your wireless MAC address.
  

• Open your Settings. You can find the Settings app on your Home Screen.
• Tap the General category.
• Tap About. This will list information about your specific device. Scroll down until you see Wi-Fi Address. This is the MAC address for your iDevice.
  

• In a terminal window type ifconfig and return.
• You'll see a list of interfaces. Your wireless interface will likely be named wlan0 or wifi0. The wireless MAC address will be in the field labeled HWaddr.
• You can also use iwconfig to find your wireless MAC address if you have it installed.
  

• Open the Chromecast app on your computer. If you have set up your Chromecast recently, you'll find a shortcut to the app on your desktop.
• Click Settings.
• Find the MAC address at the bottom of the window. The system's MAC address is located at the bottom-left corner of the Settings menu.
  

• With your Apple TV remote, navigate to the Settings icon and select it.
• From the Settings menu, select General.
• Under General, select Network.
• Your MAC address will be listed as "Wi-Fi Address".