18" x 18" Outdoor Chair Cushions – Custom Made to Your Exact Size
18 x 18 chair cushions cut to your measurements — indoor dining seats and outdoor patio frames, foam and fabric your call. Factory-direct, no minimums, ±½″ tolerance.
See the full cushion size chart — every standard size and its typical frames at a glance.
Start with your shape
Not sure? Pick the closest — every measurement is confirmed before we cut.
Don't see your shape? We make any shape.
Straight edges? A top photo + the edge numbers is all we need. Curved? Trace it on paper next to a tape measure and email us a photo.
Enter your measurements
Measure the old cushion flat, edge to edge — never the frame.
Choose your fabric
Five families, 119 cuts, one flat rate — pick by look and feel. Click a family to see its swatches below, or its ⓘ for what the fabric is and where it works best.
All covers cut to your exact dimensions — no stock sizes, zippered covers that remove for washing.
Review & order
Calculated live from your measurements — every line, no surprises.
Free shipping over $158 · $29 flat below
Estimates only — we re-verify every dimension before cutting and will contact you if anything looks off. Prefer email? Email me this quote
Odd shape or tricky frame? Upload a photo of your furniture or old cushion — one overall shot, plus a top and side view of the old cushion if you can.
JPG, PNG or WebP · up to 10 MB each · max 3
No trading company between you and the cutting table
All 119 viewable in the configurator
Cut to the dimensions you supply
Wrong build or wrong fabric, remade free
Build Your 18 x 18 Cushion
Outdoor dining chairs orbit the eighteen-inch square — compact, weather-ready frames from every big-box era, all asking for the same nominal pad and none of them agreeing on the decimals. Factory originals in our library at “18 inches” run from 18.0 to 18.5, and on a slatted outdoor frame the difference shows at every corner. The fix is not a better chart; it’s cutting to your number. Patio chair cushions in 18 x 18 are our most-replaced square — enough sun seasons to fade a cover, never enough to wear out the foam beneath.
Every 18 x 18 outdoor chair cushion is cut to the measurements you send. The documented factory reference is the Martha Stewart Charlottetown dining seat at 18.25 x 18.25 x 3.75 — charted below. Thickness 2.5 to 4 inches keeps outdoor dining height honest; Tech Fabric, our waterproof, wipe-clean leather-like weave, is the outdoor workhorse for full exposure, Cotton Linen serves covered porches and indoors. Sets from one dye lot; factory-direct, no minimums.
Close but not exactly 18 x 18? Type your numbers — decimals included — and the estimate updates as you go →
Pricing — estimated starting at
*One cushion, 18 × 18 in. (2.25 sq ft top surface): $45 make-base + 2.25 sq ft × combined foam + fabric rate ($26.47/sq ft in 35D, $27.37 in 50D, $28.69 in 65D, each at the 3-inch default). Fabric choice never moves the number — all 119 sit at one price, and the from-86 entry runs 35D at the thinnest 2-inch cut. You settle thickness at checkout; every dimension comes back to you for confirmation before cutting.
As a yardstick: U.S. specialists running custom configurators priced made-to-order cushions for common sizes (16×16 through 24×24) around $71–$119 before shipping in 2026 — numbers most buyers only see after asking for a quote. We print the formula above so you can audit the arithmetic first.
Fits these furniture series
Matching tolerance: width and depth each within 1.5 in. of 18 x 18. Chart entries come from factory-original pieces and supplier documentation. Every dimension is re-verified against your order before we cut. We are not affiliated with the brands listed — names are used for fit identification.
Exact fit in any size — get an instant quote.
If yours does not match the line above, we cut to yours all the same.
How to measure a 18 x 18 cushion
- Lay the original pad flat on a table: width across the edges, depth from front to back, thickness at the seam — leave the foam uncompressed.
- Outdoor dining height: 2.5–4 inches of thickness keeps the chair at its design; match the old pad’s side.
- Order the full dining set in one batch — one fabric lot, every chair identical.
Every step in photos, end to end: How to Measure (and Identify) Your Cushions.
Fabric Options at 18 x 18
The 18 x 18 tier decision is the classic one: Tech Fabric for open-air dining sets (waterproof, wipe-clean, indifferent to weather and children), Cotton Linen for covered porches and shade (breathable, softer hand), Premium Velvet for screened rooms and indoor dining nooks. Sets order in one fabric run so every chair matches. The climate-by-climate tier comparison is in the outdoor fabric guide.
A few from the 119-fabric lineup — review the full set, zoomed, in the configurator first.
Why 18 x 18 is the most common small square
Thickness and density at 18 x 18
Eighteen-inch squares are the workhorse of outdoor dining — the default seat pad of patio dining chairs across two decades of sets. Thickness logic is table-height logic: 2.5–3 inches keeps the sitter at the height the table was built for, and the original pad’s thickness is worth matching when you have it. A 4-inch pad on a dining chair is a bar-stool mistake in miniature — knees meet table apron.
For density, 35D covers the occasional set honestly, 50D is the every-evening standard, and 60–65D is better justified on the lounge furniture elsewhere in this library. Grade, thickness and your dimensions are confirmed together in writing before production — the remake-free tolerance (± ½ inch) starts with that confirmation.
Eighteen is where small-scale patio furniture standardized. Bistro sets, stackable dining chairs, balcony sets, and the replacement market’s workhorse frames all converge on it — and the library’s decimals tell you the convergence was loose: originals at “18” measure 18.0 to 18.5, with the Martha Stewart Charlottetown dining seat charted at 18.25 × 18.25 × 3.75. A quarter inch of spread sounds like nothing; on a slatted frame it is the difference between a pad that sits and a pad that rides up at the corners every time someone stands.
The size’s popularity is exactly why it disappoints off the shelf: the bins hold “universal” 18-inch pads cut to an average frame, and averages fit the individual about as well as averages do. The fix predates the internet — cut to the measurement — and remains the only one that works.
Sixteen, eighteen, twenty: picking the right square
The three small-even squares divide the work. Sixteen covers bistro and café compacts — the chairs that fold and stack. Eighteen, this page, is the mainstream outdoor chair floor — dining sets, balcony sets, replacement’s center of gravity. Twenty is where dining-scale comfort starts and the 20 x 20 default takes over — the size everyone believes is standard. Between them: 16.5 and 17 run import and older frames (the 17 x 17 page charts that band), and 19 appears in the library but rarely on a porch. The ladder does not stop at twenty either — the 23 x 23 lounge square and the 30 x 30 daybed square keep their own charts. If the tape disagrees with the ladder, the tape wins — every rung cuts to quarter-inch entries at the same formula.
Fabrics from the 119-option range, pictured — see all of them enlarged in the configurator before ordering.
18 x 18 indoors: dining and bistro seats
The same square does double duty inside. An 18 x 18 seat is the standard for wooden dining chairs and most bistro sets, and indoor work changes two things, not the size: the foam and the cover. Indoors we cut 45–60D high-resilience foam — firmer than the fiber-stuffed pads sold with the chairs, so the seat keeps its height under daily use — wrapped in Cotton Linen or Premium Velvet rather than solution-dyed acrylic. The measurement path is the same either way: measure the seat frame or the old pad seam to seam, whichever you are replacing.
How the pads stay put
Small squares slide, so the holding comes from the cut, not fasteners. We don’t sew on ties or gripper undersides — our factory can’t supply them reliably, so we won’t sell you the promise. A pad cut to your confirmed numbers sits the frame through daily use; on smooth composite or wicker surfaces, or wind-exposed decks, a thin non-slip rug pad trimmed slightly smaller than the cushion, laid flat underneath, is the honest fix.
Frequently asked questions
Each order is cut and sewn after you place it — 4–7 business days in production, 3–5 business days on the rush lane, and flat-rate tracked shipping. You receive a confirmation listing every dimension before any fabric is cut.
One workshop, start to finish
- Over a decade of outdoor cushion work behind each order: the cutting, filling, and sewing are all ours.
- Each dimension you submit gets a second look before the first yard of fabric is touched.
- Made when ordered — fabric and piece are yours to pick, with no floor on quantity.
- Should we miss — over ±½″ (±¾″ above 36″), wrong fabric, wrong build — the remake costs you nothing.
Custom 18 x 18 cushions from $100 — a four-step quote.
Ready when you are. Enter your measurements, pick your fabric and your finishing — every dimension comes back to you for confirmation before we cut. One cushion or a whole set, from the factory that ships them. Cut to within ½ inch of your confirmed numbers — outside tolerance, remade free.
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Reading list
Breakfast Nook Cushions: The Corner-Seating Build Guide
Breakfast nook cushion guide: L-shaped and U-shaped runs, corner geometry and seam placement, seat-plus-back builds at dining height, morning-sun fabric logic, and ordering the whole run from one fabric lot.
Cushion Shapes Guide: All 11 Shapes, What They Fit, and How to Measure Each One
A field guide to every cushion shape we cut — rectangle, chaise, L-shape, T-cushion, bowed, notched, round, oval, half-round and wedge — which furniture each one belongs to, how to measure it in inches, and exactly which shape to pick in our custom cushion builder.
Outdoor Dining Sets: Buying the Set Right So the Cushions Work
Outdoor dining set buying guide: how the set choice locks in your cushion future — seat sizes, arm heights, frame materials, cushion quality in boxed sets versus custom pads, and set versus separate buying.
Best Outdoor Furniture Materials: What to Buy for Your Climate and Budget
The material-by-material guide to outdoor furniture — teak, aluminum, steel, HDPE wicker, resin, recycled plastic and more — ranked for weather endurance, maintenance burden and cost, with the cushion spec each one implies.
Sofa Foam Cut to Size: How to Order Exact-Fit Foam
How to order sofa foam cut to size — measuring the core, adding the compression allowance, specifying density, thickness and shape, and the checklist to run before any foam is cut.
Cheap vs Quality Outdoor Cushions: Where the Money Actually Goes
What separates a $15 cushion from a $60 one and a $150 one — fabric construction, fill, stitching and covers — which upgrades matter, which are markup, and how to buy the quality your furniture actually needs without overpaying.