Custom Cushion Inserts

Cushion inserts: new cores, your existing covers

A sofa rarely dies whole. The frame is fine, the covers still fit, and what has actually gone is the foam inside — compressed where you sit, domed where you do not, sagging within minutes of standing up. A cushion insert order fixes exactly that layer: high-density foam cores cut to your measurements, shipped bare, and pressed into the covers you already own. No tools, no reupholstering, no new-fabric decisions.

What a cushion insert is — and when it is the right lane

An insert is the foam block on its own: cut, squared, shipped without a cover. It is the right buy when one layer died and the other did not — covers that still fit, close and look right, wrapped around cores that have given up. The press test settles it: flatten the seat by hand and count. Foam that rebounds instantly and holds its edges is still alive; foam that stays dished or feels brittle has failed, and no amount of fluffing brings structure back to dead foam.

The honest limit runs the other way too. Split seams, a shredded lining or fabric worn through to the weave puts money in the wrong layer — no new core fixes fabric that is gone. When covers and cores aged together, the better buy is the complete rebuild: full replacement cushions with new foam and new covers sewn to your confirmed dimensions in one order. The two lanes are laid out side by side, with real prices, further down this page.

Why choose Cushion Mill cushion inserts?

Measured for foam, not guessed

Every insert order starts from numbers, and the numbers have a discipline: measure the old core seam to seam — not the cover’s outer edge, covers stretch with age — then add half an inch to width and depth and keep thickness exact. No old core to measure? Lay the cover flat and measure the interior. Our configurator repeats these rules at the exact step where you type the dimensions, because a typo otherwise becomes your new cushion.

Density is lifespan, and it is published

Four grades, no mysteries: 35D for rarely-sat furniture, 50D for most households (5–8 years of daily service), 60D for the everyday main seat (8–10 years), 65D for commercial duty. On a typical seat the 60D upgrade costs about ten to fourteen dollars — the cheapest years-per-dollar on the page. The rate sheet behind every price is the same one the configurator quotes from.

The cover is one click away, not one vendor away

Inserts are cut in the same workshop that sews covers, so the upgrade path is an option on the same order rather than a second project. Add a sewn cover from the 119-fabric pool at a flat $7.43 per square foot — roughly $30 on a standard seat — and the insert becomes a complete cushion, with fabric choice never moving the price.

From numbers to doorstep, one accountable team

Nothing is cut until a real person re-verifies your dimensions against the order; odd numbers get a phone call, not a guess. Tolerance is a quarter inch, and a wrong cut is remade free. Standard production runs 4–7 business days, rush 3–5, shipping in 3–6 weeks, free over USD 158.

Pricing — cores from about $80, formula published

One make-base plus area at your grade’s rate, nothing hidden. Cores price at base plus foam; adding a sewn cover simply adds the fabric layer at a flat $7.43 per square foot. Worked examples at current rates:

Core (inches)	Area	50D core only	60D core only	Same core + sewn cover, 50D
16 × 16 × 3	1.8 sq ft	$80	$81	$94
20 × 20 × 4	2.8 sq ft	$106	$108	$127
24 × 24 × 4 seat	4.0 sq ft	$133	$136	$163
26 × 26 × 4 deep seat	4.7 sq ft	$148	$152	$183
20 × 18 × 3 back	2.5 sq ft	$95	$96	$113

Densities: 35D to 65D, cut per order

Inserts are cut in four grades. 35D — guest rooms and rarely-used pieces; soft, economical, honest about its service life. 50D — the household default, firm support with give, 5–8 years of daily sitting. 60D — the everyday main seat, firmer and slower to fatigue, 8–10 years; this is the grade we cut most for sofas that actually get used. 65D — commercial duty, waiting rooms and banquettes. The density question is answered honestly by hours: match the grade to how many the cushion actually serves, not to how firm you imagine wanting it. New cores always read firmer than the ones they replace — the old ones had simply gone soft.

What arrives and how it fits

How to measure foam for existing cushion covers

Three numbers per piece, one rule each. Width and depth: seam to seam on the old core, then add half an inch — the cover’s interior is slightly larger than the dead core it swallowed, and a snug core is what keeps the cover’s corners square. Thickness: exact, no allowance; this is the number the cover’s seam was sewn to close around. No old core: lay the cover flat, smooth it closed and measure the interior — never the outer edge, which includes fabric that wraps to the back.

Popular insert sizes we cut

Most sofa work lands in a narrow band of blocks, and any of them can be notched into T or L shapes at the same area pricing:

Piece	Common core sizes	Typical thickness
Sofa seat	22 × 22 to 26 × 26	4–5″ (60D recommended)
Sofa back	20 × 18 to 24 × 20	3–4″ (50D recommended)
Love seat seat	22 × 24 pair	4–5″
Club / armchair	18 × 18 to 20 × 20	3–4″
Bench / window seat core	any length to 120″	3–5″

Sizes outside the band are not exceptions — width runs to 120 inches in the configurator, and the same core-only pricing applies to settee foam, floor rounds and bench pieces.

Five easy ordering steps

1. Press-test first. Confirm it is the foam that died, not the frame or the covers — ten seconds per seat. 2. Measure. Seam to seam on the old core, add half an inch to width and depth, thickness exact; interiors if the cores are gone. 3. Configure. Enter the blocks in the rectangle configurator — or send the list with a photo for odd shapes. 4. Confirm. A real person re-verifies every dimension before the knife moves. 5. Receive and drop in. 4–7 business days standard, 3–5 rush, shipping 3–6 weeks — cores recover to full loft within hours of unpacking.

Replacing just the foam — or the whole cushion?

Most tired cushions get binned whole, when the honest diagnosis is a collapsed core in a healthy shell. If the cover still sits smooth, zips without a fight and matches the room, cushion replacement foam is the cheaper lane: keep the fabric, swap the block. Replace the entire cushion instead when the shell itself is done — seams pulling apart, fabric thinned by years of sun, or crumbling foam already working through the weave.

One measurement rule for the foam-only route: empty the cover and measure the inner cavity, not the old block. Worn foam compresses smaller than the space it came from, so ordering the tired cushion’s dimensions lands a loose, sad fit the day it arrives. Chair-scale rebuilds follow the same logic on our replacement chair cushions page — then type the cavity numbers into the customizer and see the core priced before you commit.

Frequently asked questions

What are cushion inserts filled with — foam core or fiber?

A solid high-density foam core — not loose fiber. Grades run 35D to 65D (the density guide above picks the grade for your seating). Loose fiber and down are fills we deliberately do not offer: they settle unevenly and cannot be held to a written tolerance the way a cut core can.

My cushions are flat and lifeless — will new inserts bring them back?

Yes, if the covers are still square and unsplit — new cores are the standard fix for dead foam. The test: a seat that measured 5 inches when new and reads 3.5 today has compressed foam, not a stretched cover. A fresh core at the original spec restores the loft in one order.

Do inserts come wrapped in dacron batting?

Yes — every core ships wrapped in dacron batting as standard. The wrap rounds the edges, softens the shoulder of the foam by about a quarter inch and stops the core from rubbing the cover seams. Heavier wraps are available on request.

Made and shipped by the same hands

Cushion Mill is the workshop, not a marketplace — ten years of cutting foam, one accountable team from your numbers to the box. Inserts and complete cushions come off the same benches, priced off the same published rate sheet, with a quarter-inch tolerance and free remakes when we miss it.

Keep reading: the complete foam replacement guide (press tests, density math, four ways to buy compared), insert materials compared, the couch measuring routine, and the full rebuild lanes: couch foam cushions and where to buy replacement cushions. Ready when you are: design your insert.