21x21 Outdoor Cushions

A 21″ × 21″ seat cushion fits many patio armchairs, swivel rockers and wider dining chairs. It is a size that ready-made ranges rarely stock, so most people end up with a 20″ cushion that slides around. We cut every cushion to order, so yours fits snugly between the arms.

Build a 21″ × 21″ cushionCover only
Cut within ±0.5″Free shippingShips in 2–3 weeksLifetime price match
At a glance

21″ × 21″ outdoor seat cushions

Usually fitsArmchairs

Patio armchairs, swivel rockers and wide dining chairs.

Thickness3″–4″

3″ for armchairs, 4″ for a softer lounge seat. Cut up to 8″.

AttachTies

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

Measure

Check your size

Measure the seat inside the arms, side to side and front to back.
If the back of the seat is narrower than the front, note both widths; we can cut a tapered (trapezoid) cushion.
Use your old cushion as a cross-check only: it has usually flattened and shrunk a little.
See the measuring guide for photos.
21″ wide21″ deep3″ thick · side view
How it works

Order in three steps

1

Open the builder. Your 21″ × 21″ size and a 3″ thickness are filled in; change anything you need.

2

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

3

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

Other sizes

Shop by size

16″ × 16″17″ × 17″17″ × 18″18″ × 18″18″ × 20″19″ × 19″20″ × 20″20″ × 24″21″ × 21″22″ × 22″22″ × 24″24″ × 24″25″ × 25″26″ × 26″27″ × 27″28″ × 28″14″ × 36″ lumbarAll sizes
FAQ

Questions

Is 21x21 a deep seat cushion?

No. Deep seats usually start at 24″ deep. 21x21 suits standard patio armchairs.

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

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

Can I get just a 21x21 cover?

Yes. Order cover only to fit foam you already have.

Can I order a set?

Yes. Order one cushion or a full set of 2, 4, 6 or more; there is no minimum order.