Custom D-Shaped Cushions
$67.00
Restore the half-round seat: custom D-shaped cushions for rockers, window seats and bar stools, cut to your two measurements — from USD 69.
Half a Circle, Cut to Your Two Numbers
The D-shaped cushion is a semicircle with a straight back edge — the flat side sits against the wall or frame, the 180-degree arc is where the sitter lands. It is the geometry of seats built against something: half-round window seats, corner chairs, dressing-table stools, helm seats, and the half-round stools that tuck against kitchen counters. And because the platform underneath was usually built by a cabinet installer rather than a furniture factory, no two are the same width or depth — which is why universal pads never fit one. Custom D-shaped cushions are cut to your two numbers: the flat edge end to end, and the depth from that edge out to the peak of the curve.
Open the Customizer — Half-Round Preselected →
Type the flat edge (A) and the bulge depth (D), pick thickness, foam grade and fabric, and the price appears as you type — the D area is figured as a true semicircle, not the box around it, so you are not paying for corners that are not there.
The full walkthrough — the semicircle check, the template routine, and what to do when the arc is not true — is in our D-shaped cushions measuring guide.
Pricing — Estimated Starting at $67
*One piece, 50D foam, any fabric: $45 make-base + semicircle area × foam rate + area × $7.43 fabric — the arc is figured at its true half-circle area (flat edge × bulge), not the rectangle around it. Your size is priced by your numbers in the customizer; one piece or a matched set, no minimum order.
The same D at four foam grades (36 × 18 × 4", any fabric) — density is the spec that buys years, and the per-grade step is single dollars:
Firmness is a separate dial — graded by ILD, the pounds it takes to compress the foam a standard amount — and no formula converts a D-rating to lbs/ft³. Density buys years, ILD buys feel: the two systems are unpacked in foam density explained.
How to Measure the D: Two Numbers and a Check
- The flat edge (A): end to end at the wall or frame — cut range 8–120". This is the chord of the semicircle.
- The bulge (D): square off the flat edge’s midpoint out to the peak of the curve — cut range 4–60". Not the slant from corner to peak: straight out, 90 degrees to the flat edge.
- The semicircle check: for a true half-circle, the bulge equals half the flat edge. Measure both — if they disagree, the seat is a flatter segment or a fuller bulge, all three are cuttable, but the numbers must say which.
- Thickness: seam to seam with the old pad standing on edge; 2–8" standard cuts.
When the arc resists two numbers — vintage half-rounds wearing a semicircle’s costume — trace the seat on kraft paper, label it, and photograph it flat against a tape; templates are the diplomacy that settles irregular arcs. The full routine, with the mis-measure cases we see most, is in the D-shaped cushions guide and cushion measurement mistakes.
Where D-Shaped Seats Actually Live
Rockers and gliders — the rounded-front seat platform takes a D pad in one piece; thickness 3–5" by how many hours a day it rocks. Matched sets for the whole chair are at custom rocking chair cushions.
Window-seat ends and hearth niches — where a straight run meets a rounded end, the D continues the bench around the curve: custom window seat cushions.
Bar and counter stools — the half-round stool that parks its flat side against the counter: 65D is the grade for stools that open at 8 a.m. More stool shapes at custom bar stool cushions.
Corner chairs, telephone chairs and vanity stools — small Ds at 2–3" thick; the corner chair is a D or a quarter-round, measured the same way.
Marine helm seats and radiator-cover benches — the wheel-side D and the flat-back bench over the radiator: heat and weather tolerances in boat cushions.
Edges, Fabric and Build
Every D is sewn with clean, cord-free knife-edge seams — each face a single flat fabric panel, stitched flush. No piping, no welt cord, no ties, no non-slip dots, no tufting: the flat profile follows the arc evenly, wears evenly at the curve where thighs slide across daily, and never traps debris along a raised seam. D-seats against walls hold by fit and weight.
Any of the four fabric families — Cotton Linen, Tech Fabric, Premium Velvet, Chenille — at one flat $7.43 per square foot. Stripes become rays across a D’s arc, which is either the charm or the problem; decide pattern direction before ordering. And any grade can take a Dacron wrap — a thin batting layer that softens the edge and adds about half an inch of loft; tell us the finished measurement you want, not the bare foam number.
Frequently Asked Questions
What is a D-shaped cushion?
A semicircle with a straight back edge — the shape of seats built against walls and frames: half-round window seats, corner chairs, vanity stools, bar stools and helm seats. Specified by two numbers: the flat edge end to end, and the depth from that edge to the curve’s peak.
How do I measure a D-shaped seat?
Two numbers and a check: the flat edge (A) end to end, the bulge (D) measured square from the flat edge’s midpoint out to the curve’s peak, then confirm the bulge is half the flat edge for a true semicircle. Thickness is seam to seam. The full walkthrough: D-shaped cushions measuring guide.
How much does a custom D-shaped cushion cost?
From $67 for a small vanity-stool D (17 × 8.5 × 3", 50D, any fabric) — $45 make-base plus the semicircle’s true area at foam and fabric rates. A window-seat end at 36 × 18 × 4" runs $149 in 50D. Every number is priced by your dimensions in the customizer before you order.
What thickness should a D-shaped cushion be?
2–3" for vanity stools and small pads, 3–5" for rockers and reading seats, 4–5" for a window-seat end that gets real sitting time — and always matching the original when you are replacing, because thickness sets seat height. Standard cuts run 2–8".
Do D-shaped cushions come with piping or cord?
No. Our sewing standard is clean, cord-free knife-edge seams on every shape, any fabric — the flat profile wears evenly around the arc and never traps debris along a raised seam. Nothing about the D requires a cord to hold its shape; the cut does the work.
How long does a custom D-shaped cushion take?
Made to order in 4–7 business days — rush production cuts sewing to 3–5 business days — with delivery in 3–6 weeks door to door. Arcs and templates are verified against your numbers before a single yard of fabric is cut; odd numbers get a phone call, not a guess.
Made by the Mill That Ships Them
- We are the mill — the foam is cut and the covers sewn on our floor, shipped direct. No brand, importer or retailer stands between the cutting table and your porch.
- Nothing is cut until your numbers are confirmed: every dimension is re-verified before cutting, and the semicircle check catches most bad Ds at the order stage, not the fitting stage.
- One D or a matched set — no minimum order, one run, one dye lot.
- Cut wrong — outside the ±½" tolerance (±¾" over 36"), wrong fabric, wrong build — remade free, any time you find it.
Custom D-shaped cushions from $67 — quote in four steps, confirmed before cutting.
Shipping & Delivery
- Orders over $158 ship free — add a second cushion or an upgrade and shipping’s on us.
- Smaller orders ship anywhere in the contiguous US for one simple flat fee — always shown before you pay.
- Made in 7–14 business days. Each cushion is cut and sewn to your measurements after you order, never pulled from a shelf.
- ±½″ tolerance on all custom cuts — and if we cut it wrong, we remake it free. No forms, no fine print.
Have a deadline? Contact us before ordering and we will tell you honestly whether we can meet it.