The quick answer: buy your throw pillow insert 2 inches larger than the cover, and for most homes choose a down-alternative fill — it holds the full designer shape, it's hypoallergenic, and it's machine-washable. That's the two-sentence version. Here's the complete guide: what inserts are, how the fills actually compare, the sizing chart designers use, and when to replace an insert instead of trying to revive it.
What Is a Pillow Insert?
A pillow insert is the fill — the inner cushion that gives a decorative pillow its body and shape. The cover is the fashion; the insert is the architecture. This two-part system is what makes designer pillows practical: covers zip off for washing or seasonal swaps while the same quality inserts serve you for years. It's also why a great cover over a cheap, deflated insert never looks right — the insert does the structural work.
Pillow Insert Fills, Compared
Down and feather is the traditional luxury fill — soft, moldable, with the classic "karate-chop" crease. Its drawbacks: allergens, feather poke-through, dry-clean-only care, and a higher price.
Down-alternative is a fine polyester microfiber engineered to mimic down's loft. Modern down-alternative holds the same full profile, costs less, triggers no allergies, and goes straight in the washing machine. It's what we make our made-to-order inserts from, and it's what designers increasingly specify for client homes — especially homes with kids, pets, or allergies.
Basic poly-fill (the lumpy craft-store kind) is the one to avoid: it clumps, flattens fast, and never fills corners. If a pillow looks sad in the corners, this fill is usually why.
For the full head-to-head on the first two, see our designer's breakdown of down vs. down-alternative pillow inserts.
Pillow Insert Sizing: The Size-Up Rule
The single most common insert mistake is buying the same size as the cover. A 20x20 insert in a 20x20 cover leaves empty corners and a slouched middle. Always size up 2 inches:
Cover Size |
Insert Size |
Typical Use |
20 x 20 |
Accent chairs, loveseats |
|
22 x 22 |
Standard sofas |
|
24 x 24 |
Sectionals, deep sofas |
|
26 x 26 |
Oversized seating, beds |
|
14 x 22 |
Layering, lower-back support |
|
12 x 24 (snug) or 14 x 22 (fuller) |
Slim finishing layer on sofas and beds |
Each cover size above links to that size's collection. Not sure which cover sizes your sofa or bed needs in the first place? Start with our pillow size guide for every room.
Designer tip: size your insert up 2 inches.
A 20×20 cover takes a 22×22 insert — that extra fill is what gives pillows the full, “karate-chop” designer look. Our made-to-order down-alternative pillow inserts come in every size in the chart above, plus 28×28 and long 14×36 and 12×48 lumbars.
When to Replace an Insert
Inserts are the workhorse, and they do wear out. Replace rather than revive when an insert stays lumpy or flat after washing and fluffing, has yellowed or holds an odor, or has simply aged out — basic synthetics last 2–3 years, quality fills 4–5. A fresh insert is the cheapest possible room refresh: same covers, instantly fuller pillows. Care extends that lifespan; our guide to washing pillow inserts covers each fill type step by step.
Why We Make Ours Down-Alternative
Every insert we sell is made to order in a down-alternative fill, sized for the chart above — including the in-between and lumbar sizes big-box stores skip. They're the quiet reason the pillows in 385+ five-star customer homes photograph so well: right fill, right size, full corners. Browse every insert size here, or pair them with designer covers built to be swapped seasonally.
“If you are wondering about the quality… their pillows are made of beautiful fabrics and sewn to perfection. So if you are hesitating, just buy it. You will not be sorry!”
— Charmaine T., verified buyer
Pillow Insert FAQs
What size insert for a 20x20 pillow cover? A 22x22 insert. Sizing up 2 inches fills the corners and gives the full designer profile.
What size insert for a 22x22 pillow cover? A 24x24 insert. The same size-up rule applies: 24x24 covers take a 26x26 insert.
Are down or down-alternative inserts better? Down-alternative is the better choice for most homes: same full look, hypoallergenic, machine-washable, and more affordable. Down suits purists who want a moldable, slouchy feel and don't mind dry cleaning.
Do pillow inserts really make a difference? More than the cover, honestly. The insert controls shape, fullness, and how the pillow holds up daily. A quality cover over a flat insert still reads flat.
How long do pillow inserts last? Basic poly-fill: 2–3 years. Quality down or down-alternative: 4–5 years with regular fluffing and occasional washing.
Can you wash pillow inserts? Down-alternative, yes — gentle cycle, mild detergent, low tumble dry with tennis balls. Down needs more care and often dry cleaning.
What firmness should a throw pillow insert be? Medium-full. It should hold its shape when propped but give when leaned on — the size-up rule gets you there without buying special densities.
Shop Pillow Inserts
- Down-alternative pillow inserts — made to order in every size
- All insert sizes, matched to the chart above
- Designer pillow covers — rated 4.97★ across 385+ reviews
- Shop covers by size: 18x18 · 20x20 · 22x22 · 24x24 · 14x20 lumbar · 12x24 lumbar
