---
title: "Replacement Cushion Covers: Measuring Foam You Already Own"
url: "https://cushionguide.com/guides/cushion-covers-for-existing-foam/"
section: "The Pattern Room"
author: "Élodie Marchand, The Colorist of New Orleans"
author_url: "https://cushionguide.com/masters/elodie/"
published: "2026-06-24"
updated: "2026-09-24"
keywords: "replacement cushion covers, cushion cover only without foam, how to measure for a replacement cushion cover, box cushion cover with gusset, custom zippered cover"
---

# Ordering new cushion covers for foam you already own

*Good foam deserves a second dress. The trick is to measure the insert the way the new cover will meet it: bare, relaxed, and honest about its thickness.*

> **The quick answer:** To order replacement cushion covers, measure the bare insert seam to seam while it lies relaxed, record its true thickness without rounding, and say whether it is foam, fiber or a mattress. The cover is sewn to sit snugly over exactly those numbers, so a cover sized from the old cover, or about 1 in too small, will fit badly.

![Sage green linen-look daybed covers with ivory piping on a white daybed against a pale blue wall, ladder bookshelf beside](https://cushionguide.com/media/daybed-cushions/sage-linen-look-daybed-covers-pale-blue-wall-1600.webp "Sage linen-look covers with ivory piping keep a wall-hugging daybed soft and calm against a pale blue wall. A slim ladder shelf and sheer curtains keep the corner airy.")

## The cover that came out one inch short

One inch was all it took. In one past order, a new cover came out about 1 in (2.5 cm) smaller than the foam it was made for. The cushion bulged at every edge and sat harder than it should, like bread that rose past its tin.

That is the quiet risk of **replacement cushion covers**. A cover is sewn to the numbers you send, so it is only as true as your tape. With covers for a buyer's own insert, the same slips come back: the old cover measured instead of the foam, a thickness rounded to the nearest option, a fill type left unsaid.

Measure well and the reward is lovely: the foam you trust, in a new color, for less than a filled cushion. Start at the [cushion covers](https://cushionguide.com/cushions/cushion-covers/) hub, or at [foam inserts](https://cushionguide.com/cushions/foam-inserts/) if the old foam has given up.

## Measuring the insert, seam to seam

1. **Undress the insert**: Unzip the old cover and lift the insert out. Measure the bare foam or filling, never the old cover: covers stretch, relax and change in the wash, and a copy of a tired cover is a tired cover. One exception: if the new cover will go over an inner cover you are keeping, measure with that cover on and say so.
2. **Let it lie relaxed**: Lay the insert flat on a table, not squeezed into its frame. Measure seam to seam across the top at the widest point, resting the tape on the surface rather than pressing it in. A mattress is measured at its widest and thickest point.
3. **Take length and width to the nearest 1/8 in**: Measure each side twice. A taper needs the back edge, the front edge and the depth. Anything that isn't a rectangle gets a drawing with every side labeled, such as a slight trapezoid with rounded front corners, plus a photo.
4. **Give the true thickness, not the nearest option**: Thickness is the height of the side band, the [gusset](https://cushionguide.com/glossary/#gusset) of a box cushion. If your foam is 5 1/2 in (14 cm), write 5 1/2; odd thicknesses are no problem for covers only. Leave it out, and a mattress cover can come back sized for a double layer.
5. **Name the fill**: Foam, fiber and mattresses meet a cover differently. Firm foam fills a snug cover crisply; a soft fiber insert should be about 1 in (2.5 cm) larger than its cover to look full. If you don't know what is inside, say so, and the workshop may suggest its own insert instead.
6. **Photograph the tape, then type the numbers**: Photograph the tape on each dimension, and write the numbers out as well, because tape photos get misread. Keep one unit for the whole order and put it after every number.
7. **Write 'cover only, no foam'**: Choose the nearest size range on the zippered cover listing, and type the exact length, width, thickness and fabric code in the personalization box. Then write **cover only, no foam** in plain words. The workshop double-checks every covers-only order, because some buyers believe they are buying a filled cushion.
8. **Choose the zipper and the extras**: Every cover zips fully off, with the zipper hidden on the back edge or the underside; on bench and mattress covers it often wraps two corners so the insert slides in. Ask in writing for extra-strong zippers, corner ties or a non-slip base.

## What to send for each kind of insert

| Insert | Measure | How the cover meets it | Tell the maker |
|---|---|---|---|
| Firm foam block | Bare foam, seam to seam, true thickness | [yes] Sewn to your numbers so it sits snug; foam runs slightly larger than its cover to look full | Foam, and its exact thickness |
| Soft fiber insert | Relaxed, at the widest point | [part] The insert should be about 1 in (2.5 cm) larger than the cover | That it is fiber-filled |
| Mattress | Widest and thickest point | [yes] Fitted covers run about 1/2 to 3/4 in (1 to 2 cm) under the measured thickness, since the fabric stretches | The mattress model, if you know it |
| Two stacked mattresses | Their combined thickness | [part] One cover around the stack, or one each | Which of the two you want |
| Insert with a cover you're keeping | With that cover on | [yes] Sized over the existing cover | That you measured over a cover |
| Tufted cushion | Not applicable | [no] Tufting needs the workshop's own filling, so covers only can't be tufted | Ask for a plain zippered version |

Mattress covers are zipper-only; there is no elastic, fitted-sheet version.

## A tapered chair cushion, measured twice

A buyer in the US had a tapered chair cushion and wanted a new cover only. The first numbers: 17 in (43 cm) across the back, 19 in (48 cm) across the front, 19 in (48 cm) deep and 3 1/2 in (9 cm) thick.

Before quoting, the workshop asked for the cushion to be measured again, with a photo. On a taper, half an inch at the front edge changes the angle of both sides, and a cover cut to the wrong angle never quite settles on its foam. The re-measured numbers and the photo came back together.

The buyer chose one linen for both the body and the piping. Tonal self-piping lets the shape speak instead of the trim, which is exactly right on a small seat. The foam stayed; only the dress changed.

## A spare set in a second color

Here is my favorite reason, my friends, to own good foam: it can change clothes. The workshop keeps your exact sizes, so extra covers can be ordered with the cushion or later, in the same cloth or a new one. Ordered alongside the cushion, a second cover costs roughly half as much as the cushion itself.

People use spares three ways. They change with the seasons, a washed-denim linen for July and a deep cinnamon velvet for December. They rotate on laundry day, so the seat is never bare. Or they quietly retire a color they regret. Let one color speak and the others listen: if the room already has a loud rug, the second set can be the calm one.

It works outdoors too. A buyer in the US had sound foam for a hanging porch swing, a 55 1/4 x 27 3/4 x 4 in (140 x 70 x 10 cm) seat and a 50 x 13 x 4 in (127 x 33 x 10 cm) back, and ordered cinnamon covers only, with extra-strong zippers.

Before you commit to a new shade, order swatches and look at them by a window at noon and again under a lamp. See [fabric swatches before ordering](https://cushionguide.com/guides/fabric-swatches-before-ordering/), then browse [velvet](https://cushionguide.com/fabrics/velvet/) or [linen-look fabrics](https://cushionguide.com/fabrics/linen-look-fabrics/) in the Swatch Library.

What color would you dress your foam in next, if the choice were free?

## Where cover-only orders go wrong

- ✗ **Measuring the old cover instead of the insert.** Covers stretch and relax; the foam keeps the true size.
- ✗ **Rounding the thickness to a menu option.** A 3 1/2 in insert in a 4 in cover sits loose; in a 3 in cover it bulges. Write the real number.
- ✗ **Leaving the thickness out.** A mattress cover can come back made for a double layer, twice as tall as the mattress.
- ✗ **Forgetting the fill type.** Foam and fiber meet the same cover differently; a soft fiber insert needs about 1 in more than the cover.
- ✗ **Not saying 'cover only'.** One buyer ordering corduroy covers for two twin mattresses, 74 x 38 x 10 in and 74 x 38 x 8 in, was first asked for a balance because the payment looked like a full cushion. Plain words fix it.
- ✗ **Expecting a new cover to firm up a tired insert.** A fresh cover over slouchy original filling stays slouchy. The insert decides the final look.
- ✗ **Typing ties into the size box.** Extras typed there get overlooked. Ask in writing, then check the pre-dispatch photo.

## Try the cover first in the pillow cover studio

Throw pillows are the gentlest place to practice. The [pillow cover studio](https://cushionguide.com/studio/pillow-cover-studio/) lets you choose a size, an edge and a cloth for a throw, lumbar or bolster cover, shows it on a sofa, and lists every cut piece. Measure your insert first, then build the cover around it.

For daybeds and stacked mattresses the numbers grow but the rules stay the same; [daybed mattress cover measurements](https://cushionguide.com/guides/daybed-mattress-cover-measurements/) walks through them, and [where the zipper goes](https://cushionguide.com/guides/cushion-zipper-placement/) explains the wrap-around zipper. When the new cover comes home, [wash it](https://cushionguide.com/guides/how-to-wash-cushion-covers/) at 86°F (30°C) on a delicate cycle.

> **Tailor's margin:** Measure the bare insert, not the old cover. Covers stretch and relax; the foam keeps its true size, down to the last 1/8 in.

> A replacement cover about 1 in smaller than its foam makes the cushion bulge and sit over-firm, so measure the bare insert seam to seam.
>
> — Élodie

## Two allowance rules you'll read online, and which one applies

Replacement-cover guides give opposite advice, and both are right for their own method. One tells you to round the cover up by about 1/2 in so it slides on easily; foam cutters say the reverse, cutting foam slightly larger than its cover so the fabric stays taut and the cushion looks full, with a little bulge at the zipper opening. The difference is who adds the allowance. When you order a cover here, send the insert's true length, width and thickness and add nothing: covers are cut to the insert, a little under the measured thickness because the fabric stretches, so a snug fit is intended. Adding your own half inch on top produces a loose, wrinkled cover.

## Buyer questions: covers for the foam you kept

**A common question:** If I send my insert's size, will the new cover actually fit snugly?

**The workshop's answer:** Yes, if the numbers are right. The fabric has a little stretch, so fitted covers are made about 1/2 to 3/4 in (1 to 2 cm) under the measured thickness; a mattress stack measured at 9 1/2 in (24 cm) would get an 8 3/4 in (22 cm) cover. Photograph the tape on each dimension, and say whether the insert is foam or fiber-filled.

**A common question:** What do you need from me to make a daybed mattress cover?

**The workshop's answer:** The length, width and thickness of the mattress, in inches or centimeters, for example 39 x 75 x 12 1/2 in for a twin. Always give the thickness: without it the shop may assume a double-layer mattress and make the cover twice as thick. Two mattresses stacked in one cover need their combined thickness.

**A common question:** Can you make a zippered cover for a mattress I already own, even an odd size?

**The workshop's answer:** Yes. Box-style zippered covers are made to any mattress size, from a standard twin at 38 x 75 x 8 in (97 x 190 x 20 cm) to a twin XL at 38 x 80 x 12 in (97 x 203 x 30 cm) and well beyond. The zipper can run along the long edge and piping is optional. Two mattresses of different heights go in as one order per size and can ship together.

**A common question:** Could the cover have elastic like a fitted sheet instead of a zipper?

**The workshop's answer:** Not on mattress covers; those are zipper-only. For a cover you take on and off daily, an open-bottom skirted daybed cover can be made, with a skirt that covers the front and tucks between mattress and base. Elastic covers over sofa cushions can be quoted, but they may not sit snugly on cushions that aren't square or sharp-edged.

**A common question:** I'm ordering a floor sofa. Can I add a second set of covers so I can swap colors?

**The workshop's answer:** Yes. After the sofa order, the shop sends a separate link for an extra cover set in any chart color; it can ship with the sofa or be bought later. The covers zip on and off over fillings that have their own inner covers, so you can change with the seasons or keep one set in the wash.

## Covers only, briefly

### Can a tufted cushion get a new zippered cover?

Not as a tufted cover. Tufted cushions are filled, buttoned through the filling and hand-stitched closed, so there is no zipper, and tufting only works when the workshop makes the filling. The same size can be made as a plain foam cushion with a zippered, removable cover instead.

### Are covers without foam cheaper than full cushions?

Yes. Covers only are sold in any size through the zippered-cover listing at a lower price than filled cushions. Spare covers for cushions the workshop made also fit the existing foam, and the workshop keeps your sizes for repeat orders.

### Should a new cover be bigger or smaller than the foam?

Very slightly smaller, for a crisp, full look. Firm foam is cut a little larger than its cover; the trade drafting rule is about 1/4 in per side. A cover about 1 in too small has gone too far: the foam bulges and feels over-firm.

### Can the new covers go in the washing machine?

Yes. Every foam cushion cover zips fully off, with the zipper hidden on the back edge or the underside. Wash covers at 86°F (30°C) on a delicate cycle. The inserts themselves are not washed, which is why fillings carry their own inner covers.

### What if my old foam turns out to be the real problem?

Then a new cover won't fix it; a fresh cover over slouchy filling stays slouchy. New inserts can be made along with the covers, and when a buyer's thickness or fill was unknown, the workshop has included its own inserts so the fit was predictable.

## Related at the atelier

- [What measurements do you need to make a cover for my own foam?](https://cushionguide.com/answers/measurements-for-custom-cushion-cover/): To order a replacement cushion cover, send the exact length, width and thickness of each foam piece; the thickness, or fillable depth, is what makes the cover snug.
- [Can I buy just the cushion cover without the foam insert?](https://cushionguide.com/answers/cushion-cover-only-without-foam/): Yes: a cushion cover only, without foam, is sewn to the exact length, width and thickness of the insert you already own.
- [Can I buy empty zippered covers for tufted cushions and fill them myself?](https://cushionguide.com/answers/empty-covers-tufted-cushions-own-filling/): Yes, as plain zippered covers in your exact sizes, but they will not be tufted.
- [Zippered Cushion Covers With Contrast Piping: What Goes Inside](https://cushionguide.com/readings/four-zippered-box-cushion-covers-contrast-piping/): A zippered box cushion cover is only half a cushion: its box height sets how much foam goes inside, and doubling the height from 6 in to 12 in roughly doubles the fill and the cost.
- [Custom Cushion Covers in Dusty Velvet With Contrast Piping](https://cushionguide.com/readings/dusty-velvet-cushion-covers-contrast-piping-pile/): Custom cushion covers fit best when the cover's side wall matches your insert's thickness and the length and depth are agreed as finished sizes, since handmade covers carry a 1/2 to 1 in (1.3 to 2.5…
- [Zippered Cushion Cover in Forest Green Bouclé Through the Year](https://cushionguide.com/readings/hidden-zipper-forest-green-boucle-cushion-cover/): A zippered cushion cover in bouclé works all year when the zipper runs along the back boxing seam, where it faces the wall and the loops close over the tape.
- [Cut-to-size foam vs a finished cushion: the honest comparison](https://cushionguide.com/guides/cut-to-size-foam-vs-finished-cushion/)
- [Dacron-wrapped foam: why a good cushion is cut slightly oversize](https://cushionguide.com/guides/dacron-wrapped-foam-cushion/)

*With color and care — Élodie*

---

Written by Élodie Marchand (https://cushionguide.com/masters/elodie/) for CushionGuide (https://cushionguide.com/about/). The site explains made-to-measure cushions and the partner workshop makes them; measurements are in inches first. This Markdown mirrors the page at https://cushionguide.com/guides/cushion-covers-for-existing-foam/