Key takeaways
- Square or rectangular: for chairs with a straight back rail and square corners.
- Trapezoid (T or tapered): wider at the front, narrower but still straight at the back. Common on aluminum sling and dining chairs.
- U shaped (rounded back or “tulip”): straight front, back corners fully rounded into a curve. Typical on round-weave resin wicker, bucket chairs and barrel chairs.
U shaped outdoor chair cushions are seat pads with a straight front edge and a rounded back that hugs the curve of wicker, rattan and tub-style patio chairs; to get one that fits, measure the front width, the depth at the center, and the width at the back curve, then match those three numbers rather than relying on a “fits most chairs” label. The most common size is about 19 to 22 inches wide at the front and 19 to 22 inches deep, and the right thickness is usually 3 to 4 inches for dining chairs and 4 to 6 inches for deep-seat club chairs.
Is your chair really U shaped?
Outdoor seat cushions come in three basic outlines, and buying the wrong one leaves gaps at the corners or bunched fabric at the back:
- Square or rectangular: for chairs with a straight back rail and square corners.
- Trapezoid (T or tapered): wider at the front, narrower but still straight at the back. Common on aluminum sling and dining chairs.
- U shaped (rounded back or “tulip”): straight front, back corners fully rounded into a curve. Typical on round-weave resin wicker, bucket chairs and barrel chairs.
Lay a sheet of newspaper or wrapping paper on the seat and trace it with a marker. If the back half of the outline is a smooth arc rather than two corners, you need a U shaped cushion.
How to measure in three numbers
- Front width: straight across the front edge of the seat, inside the arms. This is the number most listings call “width.”
- Depth: from the front edge straight back to the deepest point of the curve, measured in the center.
- Back width: across the seat about 3 inches in front of the back curve. On a true U shape this is usually 2 to 5 inches narrower than the front.
Round to the nearest half inch. Cushions with a cushion-to-frame gap of 1/2 inch or less on each side look fitted; more than 1 inch and the cushion slides. If your chair falls between two sizes, choose the smaller one for a tight wicker frame and the larger one if the cushion will be compressed by arms on both sides.
Use your paper template as a final check: hold it against a listing’s dimension drawing, or take it to a fabricator if you are ordering custom.
Common sizes and the chairs they fit
| Cushion size (front width x depth) | Typical thickness | Fits |
|---|---|---|
| 19 x 19 in | 2.5–3 in | Resin wicker dining and bistro chairs |
| 20 x 20 in | 3–4 in | Standard wicker armchairs, swivel bistro chairs |
| 21 x 21 in | 3–4 in | Wider wicker armchairs and rockers |
| 22 x 22 in | 4–5 in | Large wicker club chairs, round-back lounge chairs |
| 24 x 24 in or deeper | 5–6 in | Deep-seat chairs, barrel and egg-style chairs |
The 22 inch size is the most searched because many wicker club chairs fall right around 21.5 to 22.5 inches at the front. Measure anyway: two chairs that look identical can differ by an inch depending on how thick the weave is at the arms.
Fill: what makes a cushion keep its shape
| Fill type | Feel | Drying time after rain | Typical lifespan | Best for |
|---|---|---|---|---|
| Polyester fiberfill only | Soft, pillowy | Slow (can stay damp a day or more) | 1–2 seasons before it flattens | Covered porches, budget sets |
| Polyester-wrapped foam (1.8 lb density) | Supportive, rounded edges | Moderate | 3–5 seasons | Most patios |
| Reticulated (open-cell) quick-dry foam | Firm, springy | Fast; water drains through | 5+ seasons | Open patios, pool areas, rainy climates |
| Layered foam with fiber topper | Firm core, soft top | Moderate | 4–6 seasons | Deep-seat chairs used for hours |
Fiber-only U cushions are the cheapest, usually $20 to $40 each, but they lose their shape at the front edge first, which is exactly where you sit. Foam-core cushions typically run $45 to $120 each depending on size and fabric.
Fabric choices for sun and rain
- Solution-dyed acrylic (Sunbrella is the best-known brand): color is in the fiber, so it resists fading for years in direct sun. The priciest option.
- Solution-dyed polyester or olefin: good fade resistance at a lower price, slightly stiffer hand.
- Printed or piece-dyed polyester: wide pattern choice and the lowest price, but bright colors can fade within one or two sunny seasons.
Look for a removable cover with a zipper along the back curve; it lets you wash the cover and dry the insert separately, which roughly doubles the life of the cushion in a damp climate.
Ties, welts and other fit details
On U shaped cushions, ties should sit at the two points where the curve begins, not at the very back, because that is where wicker frames have uprights to tie around. Check that:
- Ties are at least 10 to 12 inches long so they wrap round-weave frames comfortably.
- The cushion has a welt (piped edge) or knife edge that matches your other cushions; welted edges hold the U outline better.
- Tufted cushions have buttons on both sides so you can flip them; one-sided tufting wears unevenly.
- The bottom has a non-slip or mesh panel if your chair seat is slick flat-weave resin.
Which cushion for which situation
| Situation | Pick |
|---|---|
| Full sun, uncovered patio | Solution-dyed acrylic over quick-dry foam |
| Covered porch, occasional use | Printed polyester with fiber fill |
| Long sitting, deep wicker chair | 4–6 in foam-core with fiber wrap |
| Kids, pets, spills | Removable zippered cover, dark or patterned fabric |
| Non-standard chair shape | Custom cushion from a paper template |
Care that keeps the curve
Stand cushions on edge after rain so water drains out of the low back curve instead of pooling. Brush off pollen and debris weekly, spot-clean with mild soap and water, and store them indoors or in a ventilated deck box over winter. Rotate cushions between chairs each season so the most-used seat does not wear out first.
