Finding the perfect pillow plumpness starts with the right insert. If you’re wondering what size pillow insert for 18×18 cover you need, the simple rule is to go bigger. An insert that is 2 to 4 inches larger in total dimensions than your cover will create a full, professional look without any sagging.
Using an insert that matches the cover size exactly often results in a flat, under-stuffed appearance. The extra size of the insert fills every corner of the cover, giving you that coveted, luxurious finish. This guide will walk you through everything you need to know to get it right every time.
What Size Pillow Insert For 18×18 Cover
For an 18×18 inch pillow cover, you should choose a pillow insert that is 20×20 inches or even 22×22 inches. This is the golden rule in home decor and upholstery work. The additional 2 to 4 inches of insert material ensures the cover is taut and the shape is well-defined.
Think of it like this: the insert is the structure and the cover is the skin. You want the structure to gently stretch the skin for a smooth look. A 20×20 insert is the most common and safe recommendation, offering a balanced plumpness. A 22×22 insert will give an even fuller, firmer look, which is ideal for covers made from thicker fabrics like velvet or linen.
Why a Larger Insert is Non-Negotiable
You might be tempted to save a few dollars or use what you have on hand. But using an 18×18 insert inside an 18×18 cover leads to several problems. First, the pillow will look deflated and cheap. Second, the corners of the cover will never be fully filled, creating a sloppy shape. Finally, it will loose its structure quickly after a few uses.
Here’s what the extra size accomplishes:
- Eliminates Corner Gaps: The larger insert pushes firmly into all four corners of the cover.
- Creates Tension: It gently stretches the cover fabric, smoothing out wrinkles and creating crisp edges.
- Improves Durability: A fully stuffed pillow maintains its shape longer and is less likely to develop lumps.
- Enhances Decorative Appeal: Fullness is associated with quality and luxury in pillow design.
Step-by-Step: Inserting Your Larger Pillow Form
Putting a larger insert into a cover can seem tricky, but it’s easy with the right technique. Follow these steps for a perfect result everytime.
- Turn the Cover Inside Out: Start by turning your pillow cover completely inside out. This gives you more control.
- Align One Corner: Reach inside and grab one corner of the cover. Place it over the corresponding corner of your pillow insert.
- Roll and Pull: With that one corner secured, start rolling the pillow insert into the cover, like you’re putting on a sock. Keep the fabric aligned.
- Flip and Adjust: Once the insert is mostly inside, flip the cover right-side out through the opening. Then, reach in and firmly pull out the other three corners.
- Final Plump: Give the pillow a good shake and punch or plump it from all sides to distribute the filling evenly. Don’t be afraid to really work it in there.
Choosing the Right Fill Material
The size is crucial, but the fill material inside the insert determines the feel and support. Your choice depends on the pillow’s purpose and your personal preference.
Down and Feather Blends
This is the classic choice for a soft, moldable, and luxurious pillow. They conform to your shape and get that “sink-in” comfort. A down/feather blend insert in a 20×20 size will give a beautiful, lived-in look. Pure down can be very soft, so a larger 22×22 might be needed for enough structure.
Polyester Fiberfill (Standard)
This is a great affordable and hypoallergenic option. It provides a consistent, medium-firm plumpness. Fiberfill inserts hold their shape well and are easy to wash. For an 18×18 cover, a 20×20 fiberfill insert works wonderfully for most decorative applications.
Memory Foam or Shredded Foam
If you need firm support, like for a floor pillow or back support on a bed, foam is the answer. Memory foam inserts are usually solid, while shredded foam is more adjustable. Because foam is less compressible, you might opt for the 20×20 size over the 22×22 to make insertion easier while still achieving fullness.
Special Considerations for Different Cover Fabrics
The fabric of your cover can influence the best insert size and type. A stiff fabric behaves differently than a stretchy one.
- Linen or Cotton Canvas: These natural fabrics have little stretch. A 20×20 insert is usually perfect, as a 22×22 might be too difficult to insert and could over-stress the seams.
- Velvet or Velvet: Velvet is thicker and has some give. You can often use a 22×22 insert for an exceptionally plush, opulent look that showcases the fabric’s depth.
- Knit or Stretchy Fabrics: Covers with significant stretch can accommodate a much larger insert. You could even try a 24×24 insert in an 18×18 stretch knit cover for a very full, casual look.
- Delicate Fabrics (Silk, Embroidery): Be cautious with delicate materials. A 20×20 insert is safer to prevent tearing or distorting intricate embroidery threads.
How to Fix Common Pillow Insert Problems
Even with the right size, you might encounter a few issues. Here’s how to solve them.
Problem: Lumpy or Uneven Filling
This is common with fiberfill inserts over time. The fix is simple: unzip the cover, remove the insert, and fluff it vigorously in the dryer on a no-heat or air-only cycle with a couple of dryer balls or clean tennis balls. This redistributes the filling. If the insert is beyond repair, it’s time for a new one.
Problem: Insert Shifts Inside Cover
If your insert seems to slide around or twist, the cover might be too big or the insert too small. First, ensure you’re using the recommended +2″ to +4″ size rule. If you are, you can add small safety pins or a few hand stitches at each corner to attach the insert to the cover’s corner seams from the inside.
Problem: Corners Won’t Fill Out
This usually means the insert is too small. Double-check your sizes. If your insert is the correct size but the corners are still soft, you can manually tug the insert’s filling toward its corners before putting it in the cover. Some inserts also have corner tabs you can pull on.
DIY: Making or Adjusting Your Own Insert
Can’t find the right size? You can make your own. Buy a bag of polyester fiberfill or shredded foam. Take an old pillowcase or sew a simple muslin sack in your desired finished size (like 20×20). Start stuffing it firmly, paying extra attention to the corners. Keep adding until it’s very full, then sew the opening closed. Remember, it will compress a bit, so over-stuff.
You can also adjust a store-bought insert. If a 22×22 is too big, you can carefully open an inner seam, remove some filling, and re-sew it. To make a smaller insert bigger, you can add extra loose fill through a seam, though this is more tricky.
FAQs: Your Pillow Insert Questions Answered
Q: Can I use an 18×18 insert for an 18×18 pillow cover?
A: Technically yes, but we don’t recommend it. The pillow will look flat and under-stuffed. For a professional, plump look, always size up your insert by 2 to 4 inches total.
Q: Is a 20×20 or 22×22 insert better for an 18 inch cover?
A: A 20×20 insert is the standard, safe choice that works for most covers and fabrics. A 22×22 insert is better if you want an extra-full, firm look or if your cover fabric is thick and has some stretch, like velvet.
Q: How do I measure my pillow cover correctly?
A: Lay the cover flat and measure from seam to seam. For an envelope or zipper closure, measure the front panel. Always measure in inches for accuracy, as pillow sizes are standardly given in inches.
Q: My pillow feels too hard with the larger insert. What can I do?
A: This might be due to the fill material. Try a down blend or a less-dense fiberfill insert. You can also manually break up a firm fiberfill insert by kneading and flexing it for a few minutes to loosen the fibers before inserting it.
Q: Where can I buy 20×20 or 22×22 pillow inserts?
A: They are widely available at home goods stores, craft stores like Jo-Ann or Michaels, and online retailers like Amazon, Wayfair, and specialty bedding websites. Always check the dimensions in the product description carefully.
Maintaining Your Perfect Pillows
To keep your pillows looking their best, fluff them regularly by shaking and punching the sides. This prevents the fill from settling permanently. Most polyester inserts can be machine washed on a gentle cycle and tumble dried on low with dryer balls. For down inserts, follow specific care labels, which usually recommend professional cleaning or a very gentle home wash with special detergent.
Always use a pillow cover or protector underneath your decorative cover if the pillow will be used for sleeping or heavy lounging. This protects the insert from oils and dirt, extending its life significantly. Rotating and flipping your cushions on the sofa also helps them wear evenly.
Choosing the right insert size is the most important step in pillow styling. By following the simple rule of sizing up 2 to 4 inches, you ensure your 18×18 covers look expensive, inviting, and perfectly finished. It’s a small detail that makes a massive difference in your home’s overall aesthetic. Now that you know the secret, you can confidently build beautiful, professional-looking pillow arrangements on your sofa, bed, or chairs.