First, something to think about: We are having a round table made and I initially wanted a smaller one with a leaf or two. My options were extremely limited (want a counter height for out room) and I thought I was going to order an Amish one when I found a local woodworker. He and his wife both said that if you want a pedastal, they would do everything they could to talk me out of extensions. They said they are great initially, but because of the weight and construcion of the table, they will always wind up having trouble. Now, he's building solid wood tables that should be around 100 years from now. If' you are buying something for the next 10 years, maybe you won't have any issues. Their advise was to go with the largest size round that fit the room and keep it stationary. That would allow you to have a rug that always fits too. No worries about storing leaves, changing finishes, etc. Are you going to have a buffet, server, china cabinet or other furniture in the room? The placement of other pieces could impact the size and shape of your rug. Search for photos of DRs with round tables. You basically have three choices -- no rug, fit the table with a round or square that is a minimum of 3-4 feet larger than the table (8-9 ft) or the rug essentially a room carpet. The size would then depend on whether you have other furniture in the room and how you want to define the space.

I have a rug under my DR table. It's a nice wool rug I found on sale at a reasonable price. As others have noted, I made sure the dimensions allowed for all chairs to be pushed back without falling off the rug. (BTW, in the photo above with the zebra rug, I don't know how one would use the chairs at that table without catching the edges of the rug... that's the most impractical set-up I've ever seen, but, yes, I do like the rest of her blog. ;-) There are a number of economical sources for large area rugs--you don't have to spend thousands. My DR rug is no more difficult to keep clean than any other area of my home.

You haven't accounted for the chairs while under the table and you have to add space to pull them out and when seated. Pull all your chairs out as far as you would need to in order to sit down and not catch the chair legs on edge of the rug. That is comfortably about 2' per chair (or an extra 4' of length and width). So you need about 7'6" x 9' minimum for table and chairs. Get the 8x10, IMO.

42"+72" = 114" 66" + 72" = 138" Is the space you need in the room in order to walk around and sit at the table and you don't have that. You usually want about 12" minimum of space around the rug so that would be 141.5" - 24"= 117.5" 102.5" - 24" = 78.5"