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 18×18 cover you need, the answer is simple: you should choose an insert that is 2 inches larger than the cover. An 20×20 inch insert is the perfect choice for an 18×18 inch cover to achieve a plump, professional look.
What Size Pillow Insert For 18×18 Cover
This rule of sizing up is the golden rule in home decor. It ensures your pillow looks full and inviting, not flat and sad. A larger insert fills the cover completely, preventing saggy corners and creating crisp edges.
Why a Bigger Insert is Always Better
Pillow covers are designed with seam allowances and fabric that takes up space. If you use an insert that matches the cover’s size exactly, it will look underfilled. The insert needs to fight against the fabric a little to create that luxurious fullness.
- A full insert prevents wrinkles in the cover fabric.
- It gives the pillow structure and a defined shape.
- The plumpness is more comfortable for leaning against.
The 2-Inch Rule Explained
For most standard pillows, going 2 inches larger than the cover is the sweet spot. For an 18×18 inch cover, this means a 20×20 inch insert. This applies to square pillows most commonly, but the principle is the same for rectangles or rounds.
Sometimes, with very thick materials like a heavy knit or velvet, you might get away with just 1 inch larger. But starting with the 2-inch rule is your safest bet for a perfect result.
Exceptions to Consider
There are a few cases where you might adjust this rule. If your cover has a complex closure, like a tight zipper or many buttons, a slightly smaller insert might be easier to manage initially. However, it will likely still need to be 20×20 to look right once it’s in place.
Choosing the Right Fill Material
The size is crucial, but the fill material determines the pillow’s feel and support. Here are your main options:
- Down: Soft, moldable, and luxurious. It requires fluffing but offers a classic sink-in comfort.
- Down Alternative: Hypoallergenic and often more affordable. It mimics down’s softness but is easier to care for.
- Polyester Fiber: Firm and very supportive. Holds its shape well and is usually the most budget-friendly option.
- Feather & Down Blend: Offers a balance of support (from quills) and softness. Can be firmer than pure down.
Fill Power and Density
For down or down alternative, look at fill power. Higher fill power means more loft and fluffiness with less weight. For polyester, consider density. A high-density poly insert will be firmer and hold up longer than a low-density one.
Step-by-Step: Inserting Your Pillow
Putting a larger insert into a cover is easier with the right technique. Follow these steps:
- Lay the cover flat inside-out.
- Place the insert on top, centered.
- Roll the insert and cover together like a burrito, starting from the side opposite the opening.
- Once rolled, flip the cover opening over the roll.
- Unroll the bundle, letting the insert slide into the cover.
- Reach in and pull out the corners of the insert into the corners of the cover.
- Fluff vigorously!
Common Pillow Insert Sizes and Pairings
Knowing the standard sizes helps you plan all your pillow projects. Here’s a quick guide:
- 12×12 cover → 14×14 insert
- 16×16 cover → 18×18 insert
- 18×18 cover → 20×20 insert
- 20×20 cover → 22×22 insert
- 22×22 cover → 24×24 insert
For lumbar pillows (like 12×20), you would typically size up to 14×22 for the same full effect.
Fixing Common Pillow Problems
Even with the right size, issues can pop up. Here’s how to solve them.
Pillow Looks Lumpy or Uneven
This is usually a sign of underfilling or low-quality fill. Make sure you’ve sized up. For down inserts, shake and punch the pillow to redistribute the fill. Sometimes, adding a bit more filler material can solve the problem permanently.
Corners Won’t Fill Out
This is often called “dog-earing.” It means the insert isn’t large enough or firm enough to reach the cover’s corners. The solution is almost always to use a larger or higher-density insert. Make sure you’re actively pulling the insert corners into place during the stuffing process.
Insert Shifts Inside the Cover
If your pillow looks great one day and messy the next, the insert is moving. Some covers have interior ties. If yours does, use them! Secure the insert’s corners to the cover’s corners with safety pins or a few quick hand stitches if there are no ties.
Care and Maintenance Tips
To keep your pillows looking plump and fresh, proper care is key. Always check the care labels on both the insert and the cover first.
- Most down alternative and polyester inserts can be machine washed on a gentle cycle. Use tennis balls in the dryer to help fluff them.
- Down inserts often require professional cleaning or very specific at-home methods to avoid damage.
- Spot clean covers when possible to extend their life between full washes.
- Fluff your pillows daily by giving them a good shake and punch. This prevents the fill from matting down in one spot.
Where to Buy Quality Pillow Inserts
You can find inserts in many places, but quality varies widely. Home goods stores often carry a range. For the best selection of sizes and fills, online retailers are excellent. Read reviews carefully, especially about how true-to-size the insert is and how well it maintains its loft over time.
Don’t forget to check craft stores for basic poly-fill inserts, which can be a great affordable option for projects.
DIY: Making Your Own Insert
If you can’t find the right size, consider making one. It’s a simple sewing project. You’ll need fabric (muslin works well) and your chosen fill.
- Cut two squares of fabric to your desired insert size (e.g., 20×20).
- Sew them together with a 1/2 inch seam allowance, leaving a 5-6 inch gap on one side.
- Turn the case right-side out.
- Stuff firmly with polyester fiberfill, down clusters, or a shredded memory foam. Pack it tighter than you think you need.
- Hand-stitch the opening closed.
FAQs: Your Pillow Insert Questions Answered
Can I use an 18×18 insert in an 18×18 cover?
You can, but it likely won’t look as good. It will appear flat and the corners may not fill properly. For a plump, store-bought look, sizing up to a 20×20 insert is highly recommended.
What if my 18×18 cover has a very tight opening?
The “burrito method” described above is your best friend for tight openings. Rolling compresses the insert, making it easier to fit through a small gap. Be patient and work the insert in gradually.
Is a down or polyester insert better for an 18×18 pillow?
It depends on your need. Down is softer and more luxe but requires fluffing. Polyester is firmer, holds shape better, and is easier to clean. For a decorative pillow that needs to keep a perky shape, a high-density poly is often the best choice.
How do I fluff a new pillow insert?
New inserts are often vacuum-packed. When you open it, let it expand for a few hours. Then, put it in the dryer on a no-heat or air-fluff cycle with a couple of dryer balls or clean tennis balls for 10-15 minutes. This will restore its volume.
My pillow still looks flat with a 20 inch insert. What now?
You might need an even firmer insert. Look for one labeled “high density” or “overstuffed.” Alternatively, you can carefully open the inner seam of your insert and add more filler material until it reaches the desired firmness.
Can I wash a pillow insert meant for an 18×18 cover?
Most are washable, but always check the tag. Use a gentle cycle with mild detergent and dry thoroughly on low heat with dryer balls. Ensure it’s completely dry to prevent mildew, which can take longer than you think.
Final Thoughts on Perfect Pillow Proportions
Getting the right insert size is the simplest way to elevate your home decor instantly. Remembering the basic rule—choose an insert 2 inches larger than your cover—takes the guesswork out of the process. For your 18×18 pillow cover, a 20×20 insert will provide the fullness and structure that makes a pillow look expensive and inviting.
Take your time selecting the right fill material for your comfort and maintenance preferences. With a little care and regular fluffing, your perfectly proportioned pillows will look beautiful for years to come. The difference it makes in your living room or bedroom is immediately noticeable and well worth the small bit of extra effort.