Could someone inform me what size is considered a 1/4 sheet cake, 1/2 and full?

At the bakery I worked at we used the following:

1/4 sheet - 9 x 13
1/2 sheet - 11 x 15
3/4 sheet - 12 x 18
Full sheet - 16 x 24

I have a 12x18x2 and it says "half sheet cake pan" on it. So I would consider two of these a full sheet cake and half of one of these as a 1/4. You'll find different places use different measurements.....always make sure your customer knows what YOU consider to be a full, half and quarter sheet.

Where i work our 1/4 sheet is 9x13, our 1/2 sheet is 12x18 and our full sheet is 18x26

Are there cake boards and boxes to hold a 18 x 26 inch cake? And where is the best place to buy them?