They are about 15" round.
I saw a tutorial on Facebook last year. I can't find it anymore, otherwise I would give credit to whom thought about this smart idea.
I will show you how I did these bead boards:
I did not trim the fabric, since it was a little loose in the rim. If it is to loose you can add bubble wrap inside the circle and then place your trays.
I used the light color fabric with the dark cover and the dark fabric with the light color cover.
I hope you like my color options.
If by chance you know whose tutorial this is, let me know and I will give credit to her.
If you buy these bead boards for this size you will be paying about $120.
These covers does not cost more $20 each.
It is a fun project!!!