I've returned two extendable dining table sets in three years. The first because the chairs didn't slide under the table when it was extended. The second because I couldn't pull the table out without hitting the wall. Both were my fault. Not the furniture's. If you're looking at an extendable dining table set with 6 chairs, you're probably measuring the room. That's good. But the room isn't the only thing that needs measuring. Here's what actually matters.
The Table Thickness: The Part Everyone Forgets
Most extendable tables have an extension leaf that lives inside the frame. When it's stored, the table top has a seam. When it's out, the leaf sits flush. What nobody tells you is that the leaf mechanism adds thickness to the table top. I measured a table at the store: 1.5 inches thick at the edge. But at the seam, it was 2.25 inches. That extra three-quarters of an inch is the difference between your chairs sliding under and scraping.
If you have chairs with arms, check the arm height against the table underside. Arms that are 24 inches tall might not fit under a 25-inch table. I had to return a set because the arms hit the table frame on the underside. The chairs couldn't be pushed in. Just stood there, stuck out into the room.
Seat Height: Measure the Chairs Too
A standard dining chair seat is 18 to 19 inches high. The table is 29 to 30. That works. But extendable tables sometimes have a thicker apron (the support under the table) to house the mechanism. That apron can be 3 inches deep or more. If the apron is too low, your knees hit it. Measure the apron height, not just the table top height.
Also measure the chairs' seat depth. I bought a set where the seats were 20 inches deep. The table was 42 inches wide. When the chairs were pushed in, the seat fronts stuck out 7 inches into the walkway. In my 10-foot-wide dining room, that was the difference between walking by and squeezing.
The Extended Length: You Need the Room, Plus a Little
When the table is extended, you need at least 48 inches between the edge of the table and the wall or furniture behind the chairs. That gives you room to push the chair back and sit down. I measured the table length (78 inches extended) and the room (11 feet). I thought it would fit. But the buffet on the opposite wall was 16 inches deep, leaving me 42 inches of clearance. That's not enough. I had to drag the table out farther than I planned.
And don't forget the leaves. Some tables come with two leaves, each 12 inches. Storing them in the frame means the table is wider than you think when closed. Check the closed width, not just the closed length. My first set was 42 inches wide closed. The second was 46 inches. That 4 inches mattered.
The Floor: Not All Floors Are Equal
If you have a rug, the chairs might catch. I have a low-pile rug, but the back legs of the chairs still snagged. I ended up putting felt pads on all six legs. That helped, but it added 20 minutes of setup and a trip to the hardware store.
Hardwood floors are forgiving. Carpet and rugs aren't. And if you have a drop-leaf or a pull-out extension, the foot of the mechanism might hit the floor seam. My house has a slight slope in the dining room, and the table wobbles when extended. Not a huge deal, but if you're eating every night, it gets old.
What Actually Decides the Buy: The Leaf Storage
Here's the thing: you'll rarely leave the table extended. It's for holidays and that one dinner party. So the leaf storage is what decides the buy. Does the leaf slide into the table, or does it pop out and lean against the wall?
Sliding leaves are more convenient, but they take up space under the table. That space is where your knees go. A leaf stored in the frame steals 2 inches of legroom. If you're over 6 feet, you'll feel it.
Detachable leaves are cheaper, but they get lost. My current set has a detachable leaf, and I've already dented it leaning it against the garage wall. It's functional, but not pretty.
And check how the leaf works when extended. Some leaves are self-storing; you pull the table apart, the leaf flips up. Others require you to lift the leaf out of a slot and place it. If the leaf weighs 15 pounds, you'll hate it. I do. My leaf is 14 pounds, and every time I pull it out, I wonder if I should've paid more for a sliding one.
The Bottom Line
Measure the table's closed and extended length, the apron height, the chair seat depth, and the arm clearance. Measure the room. But most importantly, figure out how the leaf stores. Because if you hate the leaf mechanism, you'll never extend the table, and you'll have paid for a feature you don't use.
I've been through it. Measure twice, and you won't need a third return. If you're still deciding between sets, check out what I learned about comfortable dining chairs and the one measurement most people skip on Victorian dining chairs. And if you're shopping used, read this on where the money goes wrong before you commit.
There's more in the Dining Chairs guides if you need it. Just remember: the table is the star, but the chairs and the leaf are what you'll live with every day.