DR is 12 X 15. Table seats 8 (10 in a pinch). I have 8 chairs + 2 upholstered chairs I use in the LR that can be host and hostess chairs in the DR. This is a circular table, 46" closed, with two 22" leaves. There are narrower tables, but if you have a centerpiece, they may feel crowded.

You need to allow 24" behind every seat for 'push back'.

There are several things to consider when deciding which table and chairs to buy :

--oval, rectangular, round ( I have one of each, and prefer the rectangular)

--trestle, pedestal, 4 legs (I have one of each, and prefer the trestle. Legs limit how many chairs go down the sides, and pedestals with leaves can be tippy if someone leans heavily on the end--my elderly grandfather slid the entire contents from the table onto the floor one Thanksgiving!)

--width of the front of the chair (with my oval table with 4 legs, I can only have 8 chairs comfortably with three 12" leaves. 10 chairs fit, but not comfortably.)

--do chairs have arms (only get them for the 2 ends of a rectangular or oval table, otherwise it's too hard for people to get in and out; be sure the arms will fit UNDER the table top. Mine don't, so I could only use 2 leaves in my 64" long table in my old 12' long dining room.)

--slant of back of the chair (almost straight up & down barely works ok with 30" from table edge to wall; slanted needs 36" from table edge to wall)

--how many leaves and their sizes

--width and length of table before leaves are added

--how many dishes of food to be served are usually on the table, and how many dishes are used at each place setting. (I had 22 people at 3 tables for a sit down pot luck at Thanksgiving, using both good and inexpensive china. I didn't want them clearing and stacking the dishes, since the last time I did that some pieces were chipped. This time I had them keep their finished soup bowls, salad plates, and dinner plates on the table. There were no serving dishes or center pieces on the tables. At Christmas I had lots of serving dishes in the center of the table.

So think about how you are likely to entertain family and friends. I have found that a 42" wide ~5' long rectangular (with slightly rounded corners so no one gets hurt) trestle table with 3-12" leaves covers most of my needs best.

Anne

My small DR is 10' x 9.5'. I have an oval pedestal table that is 5' x 3.5'. I have small windsor back style chairs. When I have company I can seat 6 around the table.

My dining is about 15x15, with a fireplace in one corner and a buffet and hutch down one wall. One end is open to the living, and the opening is wide enough that the table can be stretched that direction.

It's overkill, really. But my old DR was so tight that it made holiday meals a bit of a chore: people on the 'back' side of the table were trapped unless they could get the others in the traffic area to move, and it was hassle that a few more feet could cure.

My table is a hundred year old family heirloom, 48 inches wide with 7 legs and multiple leaves. The 7th is to support the center when the table is extended. It allowed us to seat 17 comfortably over Christmas, but the diners at one end were technically in the living room. Still, awfully nice to have them all in one place!

Ours is 10x13. When the leaves are in the table, it seats ten (snuggly).

Ours is 14' x 13'6". I have a 64" oval, trestle leg table with two 20" leaves. It seats 8 comfortably when both leaves are in and 10 snuggly. I wish my dining room was at least a foot longer. Our old dining room was set up like Oruboris' new one and I didn't realize how much space we borrowed from the adjoining room when we had both leaves in. I prefer a rectangle table, but in am glad I have an oval, and especially the trestle legs, because that is easier to maneuver when both leaves are in.

My dining room is 14 1/2 by 18 and can be extended into the foyer where it is open on one end. I have a large china cabinet/buffet and a dining table that seats 12 easily and I can fit another table at the end of the room and seat another
8 easily to extend to the foyer. I did this for Christmas Eve dinner and it is great to fit our whole family in one room! I was like Oruboris in that I had small dining rooms
in my previous homes and it was a chore to try to squeeze everyone in and then try to get up and out for seconds! I am so very happy with mine now! I have two open sides that feed into open areas and it is great for getting up for second and for adding extra tables if needed! Here are some pics

Our dining room is 11 x 16, and also is arranged so that we can extend the table/seating through a wide doorway into the next room for larger meals, like we did for Thanksgiving. Our regular table (rectangular with pedestal legs) is 3 1/2 x 10 ft, and can seat 10 - 12. We have a 3 1/2 x 3 ft table we can slide right up to the end of the other table, and then both together will seat 16 snugly...but the people on one end are right up to or in the wide doorway.

Oh, the chairs. Pretty average size for dining chairs (not smaller like kitchen table chairs) but none of them have arms.