Add 12" to each of the four sides, so a minimum of 9.5 feet square, but 10'x10' would be even better. General rule for table top space is 24" per diner. On a square table, you also have to account for overlap, so your table should fit eight comfortably.

If that is as big as I think, you should be able to get 2 chairs on each side. 8 total if you need that many. "rule of thumb" is that the chair is still on the rug when you have the chair pulled out and in use.

Edited answer:
For the rug, add 12" to each of the four sides, so a minimum of 9.5 feet square, but 10'x10' would be even better.

General rule for table top space is 24" per diner. On a square table, you also have to account for overlap, so your table should fit eight comfortably.

Thanks very much!! I see that some companies do make 10x10 area rugs, so that's great news.

I recently got a square dining table and was considering round rugs as well as square ones. I think I've decided not to use a rug at all.