How to Choose Decorative Pillow Covers — Size Guide for 16×16, 18×18, 20×20 & Lumbar

Decorative pillow covers come in four working sizes — 16×16, 18×18 (the standard), 20×20, and 12×20 lumbar — and the one rule that matters more than any of them: buy the insert about 2 inches larger than the cover. An 18×18 cover takes a 20×20 insert. Get that right and even an inexpensive cover looks plump and tailored; get it wrong and the corners sag no matter what you spent.

We supply blank and custom printed decorative pillow covers in bulk to decor sellers, embroiderers, and print shops, and sizing is the question behind most orders we see: which cover for which sofa, and which insert for which cover. This guide settles both — size by size, with the insert pairings in one table.

Pillow Cover Sizes at a Glance

The Insert Rule: Go 2 Inches Up

A pillow cover is cut and sewn to its stated size, but once an insert goes in, fabric has to travel over the fill — and an insert the exact size of the cover never quite reaches the corners. The result is the deflated look with floppy, empty points that makes a sofa read tired.

The fix used across the design trade is simple: size the insert roughly 2 inches up in both dimensions. The oversized insert presses fill into the corners and keeps the face of the pillow smooth and full. Interior designers have standardized on this pairing — Arianna Belle's insert guide is a good deep dive into why it works. Down and feather-blend inserts reward the full 2-inch upsize because they compress; a very firm synthetic insert can work sized just 1 inch up.

Choosing by Size: 16×16, 18×18, 20×20, Lumbar

16×16 — the layering accent

Too small to anchor a sofa on its own, 16×16 is the size that finishes an arrangement: layered in front of 18s or 20s, on armchairs where a bigger pillow would crowd the seat, and in kids' rooms and reading nooks. It's also a favorite blank for embroidery and small-format printing, because the design sits high and visible instead of drowning in fabric.

18×18 — the standard

If you only stock or buy one size, this is it. 18×18 suits standard-depth sofas, reads balanced in pairs at the corners, and is the size most patterns and printed designs are scaled for. For decor sellers, 18×18 is reliably the volume size — it fits the most homes, so it carries the fewest returns and the fewest sizing questions.

20×20 — for deep seating

Sofas have been getting deeper, and 20×20 is the answer: on a deep sofa or sectional, an 18×18 can look lost, while a 20×20 holds the corner. It's also the right scale for dressing queen and king beds. Pair it with 18s in front rather than more 20s — the step-down in size is what makes an arrangement look layered instead of lined up.

12×20 lumbar — the finisher

The lumbar is the horizontal rectangle that completes the picture: in front of square pillows on a sofa, solo on a desk chair or bench, or centered against the headboard. It's also the most forgiving place to put a statement print, because a single lumbar reads as intentional where a single small square can look stranded.

Putting Sizes Together on a Sofa or Bed

Size selection and arrangement are two halves of the same decision. The working formulas:

• Standard sofa: 18×18 at each corner, one 16×16 or a 12×20 lumbar layered in front. Three to five pillows total — odd counts read more natural than even ones.
• Deep sofa or sectional: 20×20 at the corners, 18×18 as the middle layer, lumbar in front.
• Bed: two or three 20×20 against the headboard, one lumbar centered in front.
• Armchair or bench: a single 16×16 or a single lumbar — one pillow, placed with intent.

Scale guidance like this is a starting point, not a law — a general room-by-room pillow size guide is useful for less common furniture. For pattern mixing, color, and counts in more depth, our guide to styling decorative pillows picks up where this one ends.

Fabric and Printing: Why Cotton

For covers that get decorated — printed, embroidered, appliqued — 100% cotton is the standard for a reason: it takes ink and thread cleanly, breathes instead of trapping heat, and machine washes without drama. Cotton twill adds a tighter, harder-wearing weave with a subtle diagonal texture that photographs well in product shots, which is why it's the construction decor sellers ask for.

If you'd rather have the printing done for you, our custom printed cotton twill pillow covers run the same four sizes with one-sided or two-sided printing, with a 10-piece minimum per design — send your artwork and we prepare a digital proof before anything is printed. Blank covers have no minimum at all.

Care Basics

Cotton covers are the easy-care option: remove the insert, zip the cover closed, machine wash cold with like colors, tumble dry low. Pull covers out slightly damp and smooth them flat to keep pressing to a minimum, and wash printed covers inside out to protect the design. Spot-clean inserts rather than washing them — most only need an occasional airing.

Frequently Asked Questions