Knee Bolster Pillow — Half-Round D, 3 Lengths

The knee bolster pillow: flat base, domed top

A half-round D-shaped bolster with a flat bottom that stays put and a curved top that meets the bend of a knee — three set lengths, two firmness builds, priced 20% below the custom quote. The cross-section is the whole idea: flat on the mattress, arc facing up. The flat base means it does not roll away mid-night; the domed top means the knee joint rests against a curve instead of a straight edge. Twenty inches takes both knees side by side; longer legs and bigger frames take the 24 or the 30. All set sizes, made to order in 4–7 business days — nothing to measure, nothing to confirm.

One boundary, stated first: this is a positioning and comfort pillow, not a medical device. We make no claims about swelling, pain, recovery or circulation, and nothing on this page should be read as one. If you are choosing support for a medical or post-operative need, follow your clinician’s guidance before ordering anything from anyone. What we make is firm foam in an honest D profile, sewn into a tailored cover, off the same production line as our replacement couch foam — the same cutting tables, the same 50D and 65D grades.

Set sizes and prices — pick a length

Three lengths of the same 6 × 5″ D cross-section × two firmness builds, each priced with its fitted cover included. The profile never changes; only the length does, and the price steps with it.

Every price includes the fitted woven cover and the foam core. All set sizes, made to order in 4–7 business days — the order goes straight onto the cutting list. A bolster needing other dimensions or a different profile is a conversation for the order desk, not this page.

Why the D shape works

Because a round bolster rolls and a square edge digs — the D does neither. A full cylinder needs straps or a cradle to stay put; a flat-topped block puts a hard corner into the back of the knee. The half-round splits the difference: the flat bottom is the anti-roll system (no ties, no grippers, nothing added), and the 5-inch domed crest meets the popliteal bend on a curve. The form is not new — professional massage suppliers have sold half-rounds for decades, from around $32 for small soft-foam sizes up to $55–58 for heavy-duty grades (observed across supplier catalogs, September 2026). These three SKUs sit in the heavy-duty band: 50D and 65D foam, your pick of our fabrics, shipped direct from the mill that cuts them.

Three ways it gets used

• Under the knees, lying on your back. The 20-inch length takes both knees side by side, and the domed top meets the bend of the knee instead of a straight edge digging into it. Flat bottom on the mattress, curve facing up — it stays where it is put through a night of small movements. The 24 adds turning room; the 30 runs knees to mid-calf.
• Between the knees, side sleeping. The classic: the bolster runs the length of the gap between the knees, flat base on the mattress and curve against the top knee, so the top leg rests level instead of dropping. Sleepers who want a lower profile under 4 inches of height do the same job with the wedge massage bolster.
• Firm low support in a stretching corner. On a mat, the half-round makes stable low support for a resting stretch or a supported recline; the 30-inch length carries the full calf line. It is support for stretching and rest — the firm-foam version of a studio prop, priced as furniture foam, not as equipment.

Firm or Extra Firm — how hard is hard

Firm is 50D all the way through; Extra Firm is 65D — a grade that takes meaningfully more load before it compresses.

• Firm (50D). Holds a knee pair with a small, steady give — the build most homes pick, and the one that matches the site’s standard indoor grade.
• Extra Firm (65D). For heavier frames, for bolsters that live under a working limb all day, for anyone who has watched a soft bolster flatten by mid-afternoon. Holds the same position with almost no give, and holds its shape longer. Denser foam is why the heavy-duty option costs a dollar or two more and not ten.

Density is the lifespan spec as much as the firmness spec — a 50D piece holds its cut edges for roughly 5–8 years of daily use, 65D longer still, where a low-density block dishes in months. What the D-rating means against the lb/ft³ numbers U.S. suppliers quote is laid out in foam density explained: D ratings vs lbs.

Choose from our fabrics

The cover comes from the same library as the custom line — all fabrics, one price. Color does not change the cut or the cost: choose from the swatch library — linens, canvases, performance weaves — and put your pick in the order notes at checkout. The workshop sews the cover from the swatch you named; the linen family below is what most bedrooms end up choosing.

Every bolster leaves through the same 11-point checklist

Fixed size does not mean unchecked — each order is read and verified before it ships. The list the workshop runs on every half-round:

1. Foam density verified against the mill certificate before the block is touched — 50D means 50D, 65D means 65D.
2. Length cut to the listed size and checked against the cutting list, ±½″ tolerance.
3. D-profile checked against the half-round template — flat bottom, 6-inch width, 5-inch crest.
4. Both end faces cut square to the length, walked clean of steps.
5. Cover fabric pulled from the same dye lot family as the swatch you named in the order notes.
6. Cover panels cut with the weave running true along the length, seams aligned at the crest.
7. Seams sewn flat knife-edge throughout — no welt cord, no piping, no tufting, no buttons.
8. Crest seam and both end closures walked twice at the stress points.
9. Finished cover fitted on the finished core — not measured flat, fitted.
10. Vacuum-compression pack test: the foam must loft back to cut dimensions within 24 hours of unwrapping.
11. Label attached with length, density and firmness build before the box is sealed.

The honest limits of a set-size half-round

Three lengths, one profile, no curves cut to order on this page — stated before you order rather than after.

• Positioning and comfort, not medical claims. No swelling, no pain relief, no recovery, no circulation — the page describes what the shape does and nothing further. For medical or post-operative support, follow your clinician’s guidance on what is appropriate.
• The sizes on this page are the sizes. A bolster that needs to be 26 inches long, or 8 inches tall, or a different shape entirely is a custom piece — that conversation starts at the order desk. Choosing between three options is the trade you make for the 20%.
• Nothing is added to hold it in place — nothing needs to be. No ties, no straps, no non-slip grippers: the flat base is the anti-roll system, and a bolster that needed sticky help was cut wrong.
• Made to order means days, not same-day. Cut and sewn after the order lands — 4–7 business days standard. A marketplace block that ships tomorrow is the honest answer for this week; it will not be 50D/65D foam with a 119-fabric cover.

Frequently asked questions

Made by the mill that cuts them

• Ten years of cutting foam and sewing covers on our mill floor — a half-round is the same blade and the same sewing, one profile over.
• The densities and the 119-fabric library are the same options offered on every custom piece — nothing on this page is a cheaper line.
• Fixed sizes still get checked: each order is read against the cutting list before the foam is touched, and odd requests get a person replying, not a guess.
• If we cut it wrong — outside the ±½″ tolerance — the piece is re-cut free, any time.

Which length fits which sleep style — back sleepers under both knees, side sleepers between them — is covered in the knee bolster comfort guide, and the table-side ramp form lives on the massage table wedge bolster page.

Shipping & Delivery

• 4–7 business days to cut and sew, then shipped direct — typical US custom shops quote 3 to 6 weeks; rush production (3–5 business days) is available on request.
• Shipping is a single flat rate per order with tracking; every order can be cancelled free within 24 hours of placement.
• Bolsters ship vacuum-compressed — flat is normal, and the foam lofts back to its cut dimensions after unwrapping (24-hour recovery standard).
• A real person from the workshop answers within one business day.

Knee bolster pillows from $56 — three set lengths, two builds, our fabrics, no measuring required. Tell the workshop which length and build →