Let's talk about benches. We'll break this down into a few sections.
A dining bench is a bench up next to a table that you would eat at. There are different versions of bench seating at a table. The three main ones are: built in banquette benches, benches connected to the table like a picnic table, and independent benches. In this blog I'll only be talking about benches that can move independently from the table.
So this is relative to the size of the table, and a little bit about your taste. The longest an independent bench should be is the length of the table. This gives a bit of a picnic table look, especially with a bench on both sides. Another option for a bench is 12 inches or 1 foot shorter than the length of the table. This is a little closer to where chairs land at a standard table. This can be an especially good look if you only want a bench on one side.
Another important facotr when it comes to the length of the bench is if you want it to tuck under the table. Not all table legs allow this, and some don't impact it at all. However, the style of table that this is most important for is parsons tables. These tables have legs in the 4 corners, so a well sized bench can fit between the legs of the table and tuck in. The exact length of this depends on the style of parsons table you have. But for a parsons dining table, I'd recommend a parsons bench that tucks between the legs.
Yes! 2 other things worth mentioning.
Long benches can be awkward, 7-8 feet can be a little obnoxious to slide all the way down. This can cause people to want to step over the bench. Stepping over the back of the bench can also be awkward.
Also, a racetrack oval dining table has a long straight side, and then a curve. A bench running along the straight side should be about the length of the straight side.