How Long a Bench Needs to Be Per Person

Benches are bought by length and used by shoulder, and the two numbers rarely agree. Here is the arithmetic, the difference between a bench at a table and a bench against a wall, and an honest answer for a 1600 mm one.

Three numbers

Situation	Per person	Why
At a dining table	600 mm	Elbows out, place setting width, cutlery in use
Against a wall, sitting	500 mm	Arms in, no table, shorter stays
Hallway, putting shoes on	450 mm	One person at a time, or two who know each other

Adult shoulder width is roughly 400 to 500 mm. The spacing above is shoulder width plus the gap that stops two people touching, which is what people actually object to.

A 1600 mm bench, honestly

Divide and then be realistic about who is sitting.

• Two adults: 800 mm each. Generous.
• Three adults: 533 mm each. Comfortable at a table, roomy against a wall.
• Four adults: 400 mm each. Shoulder to shoulder, and at a dinner table with cutlery it is a squeeze everyone remembers.
• Four, two of them children: works well, because a child occupies roughly 350 mm.

So the useful answer is three adults, four at a family table. The Concrete Bench is 1600 mm long and 400 mm deep, which puts it exactly on this line: three in comfort, four for a Sunday lunch with children in the middle.

Depth changes what the bench is for

A 400 mm deep bench is a dining and transitional depth. You sit with your feet under you, upright, and get up easily. It is the right depth to push under a table and the right depth for a hall.

A 450 to 500 mm depth starts to be a seat you sink back into, which only works with something to lean on. Deeper than that without a back and people perch on the front edge, which defeats the depth entirely.

At a table, two extra constraints

1. Table legs. A bench has to slide between them, or stop short of them. Measure the clear distance between legs, not the table length. A 1600 mm table with legs 100 mm in from each end gives you 1400 mm of clear run.
2. Overhang. You want the bench to tuck under, which means the table needs an overhang past its apron or base of at least 250 mm for knees, plus the bench depth to disappear.

Seat height and the gap under the table matter as much as length, and both are covered in the gap between chair seat and table top.

Weight and floor

A long bench concentrates its weight at two supports. The Concrete Bench is 84 kg on two folded steel plates, which is fine on tile and worth spreading on soft timber. Pressure is weight divided by contact area, so a pad that runs the full length of each plate solves it. See protecting floors under heavy furniture and, for apartments, heavy furniture and floor load.

Levelling matters more on a bench than on a chair. A rigid bench resting on three of four contact points bends across its length every time someone sits in the middle, which is a real cause of cracking in cast pieces.

The social arithmetic nobody mentions

A bench holds more people than chairs in the same length, and people use it as though it held fewer. Strangers leave a gap. Family do not. A 1600 mm bench that seats four at a family table seats two in a public hallway, because the middle positions go unused.

If the bench is for guests, plan at 600 mm. If it is for your own household, 500 mm is realistic.

Before you buy

1. Decide the situation: table, wall or hall.
2. Multiply the people by 600, 500 or 450 mm.
3. At a table, check the clear distance between the table legs rather than the table length.
4. Check the depth suits the use: 400 mm to sit up, more only with a back.
5. Check the weight against the floor and plan to level it properly.

Reality check

• Four adults on 1600 mm is a number, not a plan. Three is the comfortable answer.
• Children change the arithmetic more than any other factor.
• Table legs, not table length, decide what fits underneath.
• Backless means short sits. Accept it or buy chairs.
• Level a heavy bench properly. It is a structural matter, not a comfort one.