Will a Seat Cushion Make My Chair Too High for the Table?

Updated November 2026 · By Sam K, Fabrica Kraft

Quick answer: A cushion makes a chair too high when the gap between the top of the cushion and the underside of the table drops below about 10 inches. Measure from the floor to the lowest edge under your table top, subtract 10 to 12 inches, and that is the highest your cushioned seat should sit. With a standard 30-inch table and an 18-inch chair seat, that usually leaves room for a cushion of about 1 to 2 inches.

It is one of the most common surprises with new dining chair cushions: they look perfect, then the first time someone sits down their knees bump the table. The fix is not a thinner cushion by guesswork. It is one measurement and a bit of simple math, done before you order.

The rule: 10 to 12 inches between seat and table

Furniture makers and designers aim for about 10 to 12 inches (25 to 30 cm) between the chair seat and the underside of the table. That space is what your thighs need to slide under the table comfortably.

• A standard dining table is about 28 to 30 inches from the floor to the tabletop.
• A standard dining chair seat is about 16 to 19 inches from the floor, with 18 inches the most common.
• A cushion adds its thickness to the seat height, so it eats into that 10 to 12 inch gap.

Measure to the lowest edge, not the tabletop

This is where most people go wrong. Your knees don't hit the tabletop; they hit whatever hangs lowest under it. Many tables have an apron (the wooden rail that runs under the edge) or a thick top that drops lower at the edge.

1. Measure from the floor straight up to the lowest point under the table edge where you sit: the bottom of the apron, or the underside of the top if there is no apron.
2. Measure the height of the bare chair seat, from the floor to the top of the seat at the front edge.
3. Subtract the seat height from the table measurement. That is the gap you have today.
4. Take away 10 inches. Whatever is left is roughly the most cushion you can add.

Worked example: the bottom of the apron is 27½ inches from the floor and the bare seat is 17 inches. The gap is 10½ inches, so there is only about ½ inch to spare: a thick cushion will push knees into the apron. A thin, firm 1-inch pad is the most this table can take.

Quick chart: how thick can the cushion be?

Find the height under your table edge and your bare seat height. The number shows roughly the most cushion you can add while keeping a 10-inch gap.

"None" means the chair already sits close to the table; a cushion will crowd your knees unless the chair or table changes. For a little more comfort, aim for an 11 to 12 inch gap and go one size thinner.

A cushion sits lower once you sit on it

Foam gives a little under your weight, so the seat height you feel when sitting is lower than the cushion's height when the chair is empty. How much depends on the foam: soft foam sinks more, firm foam less.

• Tight table? Choose a thin, firm cushion. It adds padding without much height, and it keeps its shape over years of daily use.
• Plenty of room? A slightly thicker cushion with a softer top feels more like an upholstered chair.
• Test before you order. Fold a towel to the thickness you are thinking of, put it on the chair and sit at the table for a minute. Check your knees, and check your feet still rest flat on the floor.

For thin dining pads we use our firm Luxury foam, which suits seats from 1 to 3 inches thick. You can compare foams on our foam page, and read why a fresh firm cushion can feel stiff at first in my new cushion feels too firm.

Why ready-made cushions often get this wrong

Most ready-made chair pads come in one or two thicknesses, so you get whatever the shop stocks, not what your table allows. A custom cushion lets you choose the exact thickness for your table, along with the exact width, depth and shape of the seat, so it doesn't overhang or slide.

Browse dining and kitchen chair cushions, made to your size and thickness. For benches and banquettes, the same rule applies: see our guide to measuring a bench cushion and the bench cushion builder.

What if the chair is already too high?

• Skip the cushion on chairs that already have an upholstered seat, or choose the thinnest firm pad.
• Check the table, not just the chair. A table with a deep apron is often the real problem; a table with a slim top or no apron gives back an inch or more.
• Counter and bar stools follow the same idea with taller tables. Measure the counter's underside and keep a similar gap.

Frequently asked questions

How thick should a dining chair cushion be?

For most dining chairs at a standard 30-inch table, 1 to 2 inches. Measure the gap under your table first: if you have more than 12 inches, you can go thicker.

How much space should there be between a chair and the table?

About 10 to 12 inches between the seat and the lowest edge under the table. Less than that and knees and thighs start to rub.

Does a cushion squash down when you sit on it?

Yes, a little. Soft foam sinks more than firm foam, which is why a firm cushion is the better choice when the table is tight.

Can you make a chair cushion in a thickness that isn't standard?

Yes. Our cushions are made to order, so you choose the thickness along with the size and shape. Every cushion is cut to within ¼″ (maximum ±1″) of your measurements.

Sources

• IKEA: Dining chair size guide
• Inside Out Contracts: Seat height to table height guide
• Planner 5D: How tall is a dining room table?