18x20 Outdoor Chair Cushions

An 18″ × 20″ cushion fits many patio dining chairs with a deeper seat. These are some of the most searched outdoor chair cushion sizes, but chair seats vary a lot, and many taper toward the back. We make every chair cushion to your exact measurements, including tapered and rounded-front seats.

Build an 18″ × 20″ chair cushionCover only
Cut within ±0.5″Free shippingShips in 2–3 weeksLifetime price match
At a glance

18″ × 20″ chair cushions

Usually fitsPatio dining chairs

Fits many patio dining chairs with a deeper seat.

Thickness2″–3″

2″ for dining chairs, 3″ for more padding. Up to 8″ is possible.

AttachTies

Matching-fabric ties at the back corners are standard. Velcro on request.

Measure

Check your size

Measure the seat at its widest point side to side, then front to back. An 18″ × 20″ seat is usually 18″ wide and 20″ deep.
If the back of the seat is narrower than the front, note both widths; we can cut a tapered (trapezoid) cushion.
Note where the chair uprights are so ties sit in the right place. See the measuring guide.
How it works

Order in three steps

1

Open the builder. Your 18″ × 20″ size and a 2″ thickness are filled in; change anything you need.

2

Choose Sunbrella fabric, foam and ties. Not sure on colour? Order a swatch.

3

We cut within ±0.5″ and ship in 2–3 weeks, with free shipping.

Other sizes

Shop by size

22″ × 22″24″ × 24″25″ × 25″26″ × 26″27″ × 27″28″ × 28″17″ × 17″18″ × 18″18″ × 20″All sizes
FAQ

Questions

Is 18x20 a standard patio chair cushion size?

It is common, but chair seats vary by brand. Measure your seat and enter the exact size.

My seat is wider at the front. Can you match it?

Yes. Order a trapezoid cushion with the front and back widths.

Can I order a set?

Yes. Order one cushion or a full set; there is no minimum order.