Finding the right pillow insert can make or break the look of your decorative throw pillows. If you’re wondering what size pillow insert for 12×20 cover you need, the simple answer is to go one size up. A 14×22 insert is usually the perfect choice to achieve that full, professional look.
Using an insert that’s slightly larger than your cover ensures there are no saggy corners or empty spaces. This guide will walk you through everything you need to know about pairing inserts with covers, especially for less common sizes like a 12×20 lumbar or bolster style.
What Size Pillow Insert For 12×20 Cover
For a 12×20 inch pillow cover, the ideal insert size is 14×22 inches. This is known as the “plus-two” rule, where you add two inches to both the length and width of the cover’s dimensions. The extra fullness provided by the larger insert fills the cover completely, creating a plump, inviting pillow without any wrinkles or slack fabric.
Why not use a 12×20 insert? An insert that matches the cover’s exact measurements will often look flat and understuffed. Over time, it can shift and become lumpy. The goal is to have the insert gently stretch the cover fabric for a crisp, luxurious finish.
Understanding Pillow Insert Sizing Rules
The general rule for decorative pillows is simple: your insert should be 2 to 4 inches larger total than your cover. For a square 20×20 cover, you’d use a 22×22 insert. For an 18×18 cover, a 20×20 insert is best. This rule applies to most standard shapes.
Here’s a quick reference for common cover sizes:
- 16×16 Cover: Use an 18×18 or 20×20 Insert
- 18×18 Cover: Use a 20×20 Insert
- 20×20 Cover: Use a 22×22 Insert
- 22×22 Cover: Use a 24×24 Insert
- 12×20 Cover: Use a 14×22 Insert
The material of your insert also plays a role. Down or down-alternative inserts compress more easily, so you might even consider going 3 inches larger. Firmer polyfill inserts hold their shape well, so the 2-inch rule is often sufficient.
Why a 14×22 Insert Works Best for a 12×20 Cover
A 12×20 cover has a unique, elongated lumbar shape. A 14×22 insert provides the necessary extra volume in both directions. The added length and width ensure the corners are fully filled, which is crucial for a rectangular pillow. If you use a 13×21 insert, you might find the ends are still a bit empty.
When you stuff the larger insert into the cover, it might seem tight at first. That’s normal! Gently push the insert into all corners, give it a good fluff, and you’ll see the cover become smooth and taut. The pillow will look professionally made, not homemade.
Step-by-Step Guide to Inserting Your Pillow
Getting a larger insert into a cover doesn’t have to be a struggle. Follow these steps for a perfect result every time.
- Lay your 12×20 cover flat with the opening facing up.
- Fold your 14×22 insert in half lengthwise, then fold it in half again.
- Slide the folded insert into the center of the cover opening.
- Once the main body is in, reach in and pull out each corner of the insert into the corresponding corner of the cover.
- Shake the pillow vigorously and then smack it gently with your hands to distribute the filling evenly.
- Fluff the finished pillow and allow it to expand for a few hours before final placement.
Choosing the Right Fill Material
The size is critical, but the fill material determines the pillow’s feel and maintenance. Here are the main options.
Down and Feather Blends
These offer a luxurious, soft, and moldable feel. They compress easily, making them easier to stuff into a tight cover. However, they require regular fluffing and can trigger allergies. For a 12×20 cover, a down blend in a 14×22 size will give a very soft, sinkable look.
Down Alternative (Polyester Cluster)
This is a popular, hypoallergenic choice that mimics the softness of down. It’s usually more affordable and easier to care for, often being machine washable. A down-alternative 14×22 insert will provide a plump, consistent shape for your cover.
Solid Polyester Fiberfill
This fill creates a firmer, more structured pillow. It holds its shape extremely well and is very budget-friendly. If you prefer a stiffer, more supportive lumbar pillow, a fiberfill insert is a great choice. Just ensure it’s a high-density fill so it doesn’t go flat quickly.
What If You Can’t Find a 14×22 Insert?
While 14×22 is the ideal size, it’s not always available at every store. Don’t worry, you have several good alternatives.
- Use Two Smaller Inserts: Two 12×12 square inserts placed side-by-side can fill a 12×20 cover nicely. You’ll need to arrange them carefully to avoid a seam in the middle.
- Custom Order: Many online retailers offer custom-sized pillow inserts. You can order the exact 14×22 dimensions you need.
- Size Up and Adjust: Purchase a larger standard size, like a 16×24, and carefully unstitch one seam to remove some filling. Then, re-sew the insert to your desired 14×22 dimensions. This takes a bit of sewing skill.
- Use a 12×20 with a Topper: Start with a 12×20 insert and add a thin layer of extra batting or polyfill around it before putting it in the cover. This adds the missing volume.
Common Mistakes to Avoid
Even with the right size, a few errors can ruin the final look. Watch out for these common pitfalls.
- Using an Exact-Match Insert: This is the number one mistake. A 12×20 insert in a 12×20 cover will look sloppy and flat.
- Choosing the Wrong Firmness: A too-soft insert won’t fill out the corners, even if it’s the correct size. For structured covers (like linen or velvet), opt for a firmer fill.
- Not Fluffing Regularly: All pillows, especially down, need daily fluffing to maintain their shape and prevent the fill from clumping in one end of the lumbar shape.
- Forgetting to Check Closure Type: Ensure your cover has a secure closure (like a zipper or envelope) that can handle the pressure of a overstuffed insert without popping open.
Care and Maintenance for Your Pillows
To keep your 12×20 pillows looking fresh, proper care is essential. Always check the care labels on both the cover and insert first.
Most removable covers can be machine washed on a gentle cycle and tumble dried on low. For the insert, spot cleaning is often safest. Down and down-alternative inserts can sometimes be machine washed with gentle detergent, but they must be dried completely on low heat with tennis balls to break up clumps.
For fiberfill inserts, vacuuming with an upholstery attachment can remove dust. Using a pillow protector between the insert and cover can significantly extend the life of both pieces by shielding them from oils, sweat, and stains.
FAQs About Pillow Insert Sizing
Can I use an 18×18 insert for a 12×20 cover?
No, that won’t work well. An 18×18 is a square insert, and a 12×20 is a rectangular lumbar shape. The square insert will bunch up awkwardly inside, leaving the ends of the cover empty and creating a round, lumpy shape instead of a long, neat one. Always match the shape of the insert to the shape of the cover.
My cover is envelope closure. Will a larger insert break it?
It shouldn’t if you size correctly. A 14×22 insert in a 12×20 envelope cover is standard practice. The tension helps keep the pillow looking full. However, be gentle when inserting it. If the envelope flap seems strained, you can hand-sew a few discreet stitches at the ends of the opening to reinforce it after the insert is in.
Is down or down alternative better for a lumbar pillow?
It depends on your needs. Down gives a softer, more decadent “slouch.” Down alternative offers a similar plushness but is hypoallergenic and often easier to clean. For a lumbar pillow used for back support on a bed or sofa, a firmer down alternative or even fiberfill might provide better structure and maintain its supportive shape longer.
How do I measure my pillow cover correctly?
Lay the cover flat and measure the seam-to-seam width and length. Don’t measure the outside while it’s stuffed. For a 12×20 cover, it should measure 12 inches on the shorter sides and 20 inches on the longer sides when completely flat and empty. If your cover is already made, these dimensions should be provided by the seller.
What if my pillow cover is a tight weave like linen?
Tight-weave fabrics like linen or canvas have less stretch. For these, you might stick to the 2-inch larger rule (14×22) rather than going bigger. A 15×23 insert could be too difficult to insert and might stress the seams. A down insert, which compresses more, can be easier to use with these stiff fabrics than a firm fiberfill one.
Final Tips for a Perfect Finish
Remember, the key to a beautiful decorative pillow is in the foundation. Taking the time to choose the correctly sized insert makes all the difference. For your 12×20 cover, start your search for a 14×22 insert. Feel the density in store if you can, or read reviews online to gauge firmness.
Don’t be afraid to return an insert if it doesn’t create the look you want—either because it’s too limp or too stiff. The right insert will make your cover look it’s best and last for many years. With these tips, you can confidently answer the question of what size pillow insert for 12×20 cover and achieve a designer-style result in your own home.