The flag of Guernsey consists of a white background with a red cross that extends to the edges of the flag. In each of the four quarters created by the cross, there is a smaller yellow cross. The aspect ratio of the flag is 3:5, and the geometric properties are rectangular. The color codes for the flag are:

• White: #FFFFFF
• Red: #FF0000
• Yellow: #FFFF00

There are no specific measurements given for the flag's dimensions, but it typically follows the standard dimensions for national flags.