Quick answer: Make your crochet pillow cover about 5 to 10 percent smaller than the insert, not the same size. Of 24 free crochet pillow patterns, only 8 state both the insert size and the cover size, and among those the median allowance is zero. Half make the cover exactly as wide as the insert, which is what gives you a flat, loose pillow with empty corners. Crochet stretches, so a cover made to size ends up larger than the form inside it.
You make a cover that looks perfect flat on the table, push the insert in, and the whole thing slumps. The corners are empty and the fabric slides around the form. I made an 18 inch cover for an 18 inch insert because the pattern said so, and it did exactly that.
It is not your tension. The pattern gave you one number and never said which end of the pillow it described. Below are ten insert and cover cases, each with the size to aim for.
Cover width = insert width minus 5 to 10 percent. An 18 inch insert wants a cover of 17.1 to 16.2 inches.
Before you start, you can try the sums on a small square. the Color Block Square is a good one to practise on.
What you need before you start
- Your insert, measured flat. Lay it down and measure across the middle, because a plump 18 inch form often measures 17 across.
- Your yarn and hook. The same ones you plan to use, so the swatch tells the truth.
- A tape measure. You will check the front panel against the form before you seam.
- A yarn needle. You need it to seam all four corners fully.
- A pencil. Write the target width in inches, because inches survive a change of stitch or hook.
The stitch you pick changes the width you get for a given chain. That is a separate correction, and my crochet stitches for blankets guide lists how wide each one runs. the Crochet Pattern Granny Square PDF Video is a clear example of a square you can seam into a panel.
1. 14 inch insert: a 13.3 to 12.6 inch cover
Take 5 percent off 14 and you get 13.3 inches. Take 10 percent and you get 12.6.
A small cushion has little room to hide a mistake. Use the 13.3 end for dense stitches and 12.6 for open ones. A square to check your sums against is the Color Block Square.
2. 16 inch insert: a 15.2 to 14.4 inch cover
A 16 inch form wants a cover between 15.2 and 14.4 inches.
This is a common size for a sofa corner. Hold the front panel against the form and it should sit slightly short of the edges on every side. A square to check your sums against is the Crochet Pattern Granny Square PDF Video.
3. 18 inch insert: a 17.1 to 16.2 inch cover
This is the size most patterns use. Your cover target is 17.1 to 16.2 inches.
A pattern that says 18 and means the cover will give you a flat pillow. A 20 inch form fills an 18 inch cover that has already been made too big. A square to check your sums against is the Granny Square Crochet Bag.
4. 20 inch insert: a 19 to 18 inch cover
A 20 inch form takes a cover of 19 down to 18 inches.
At this size the stretch builds up over more inches. You will see the sag sooner if you skip the reduction. A square to check your sums against is the Color Block Square.
5. 22 inch insert: a 20.9 to 19.8 inch cover
For 22 inches, aim for 20.9 to 19.8.
One pattern in my sample makes a 22 inch cover for a 24 inch insert. All the patterns that address fit call the finished pillow firm rather than tight. A square to check your sums against is the Crochet Pattern Granny Square PDF Video.
6. 24 inch insert: a 22.8 to 21.6 inch cover
A 24 inch form wants 22.8 to 21.6 inches.
This is the biggest size here. It is also where a cover made to the insert size looks the emptiest. A square to check your sums against is the Granny Square Crochet Bag.
7. Envelope back: the extra inch is overlap
An envelope back cover made 19 inches wide for an 18 inch insert looks like a larger cover. It is not.
That extra inch is not ease for the pillow. It is the overlap at the back, which is a different thing wearing the same number. A square to check your sums against is the Color Block Square.
8. Lumbar pillow: take the percentage off the short side
On a rectangular form, the long side needs proportionally less reduction than the short one.
The stretch is spread over more inches along the length. Take the 5 to 10 percent off the short side and keep the long side close to true. A square to check your sums against is the Crochet Pattern Granny Square PDF Video.
9. Round cushion: work to the stated diameter
Diameter does not behave like width. A circle pulled tight over a round form turns into a dome.
Work a round cover to the stated diameter and control the fit at the depth instead. A square to check your sums against is the Granny Square Crochet Bag.
10. Deep insert, six inches thick: measure over the form
One pattern in the sample is written for a form six inches thick. The cover has to travel around the depth as well as the face.
A flat percentage off the face leaves you short. Measure right over the form with a tape and use that number. For thick chunky yarn, see the chunky yarn pillow guide. A square to check your sums against is the Color Block Square.
How patterns size covers: 24 patterns, one number
Across 24 published free crochet pillow patterns, I recorded whether each one states the insert size and the finished cover size.
| What the pattern states | Patterns | Share of 24 |
|---|---|---|
| Both insert and cover size | 8 | a third |
| Insert size only | 11 | almost half |
| Cover size only | 4 | a sixth |
| Neither | 1 | one pattern |
| Anything about fit | 6 | a quarter |
- Read the middle column to see how many patterns name each number.
- Two thirds hand you one measurement and leave you to guess.
- Only 6 say anything about fit at all.
The median allowance among the 8 that state both is zero percent. The range runs from 10.5 percent smaller to 5.6 percent larger, a spread of 16 points on a decision most patterns never admit to making. Woven fabric does not give, so a woven cover is cut to size. Crochet gives in both directions, and it gives more once the form pushes outward. For a pattern to compare against, try the Granny Square Crochet Bag.
Seven steps from insert to seamed cover
Step 1: Measure the insert, do not trust the label
Lay it flat and measure across the middle, not corner to corner. A plump 18 inch form often measures 17 across the flat.
Step 2: Take 5 to 10 percent off
That is your target cover width. Use the smaller cut for dense stitches and the larger for open ones such as granny squares or shells.
Step 3: Swatch, and measure under tension
Measure the swatch relaxed, then pull it gently sideways and measure again. The gap tells you how much give your fabric has.
Step 4: Multiply the target width by your stitches per inch
For a form of 18 inches, a cover of 16 to 17 inches at 4 stitches per inch is 64 to 68 chains, adjusted to the stitch repeat.
Step 5: Work both panels to the target
Work the front and back the same size. Add the turning chain, and round up to the repeat, never down.
Step 6: Check on the form before seaming
Hold the front panel against the insert. It should sit slightly short of the edges on all four sides. If it covers the face with room to spare, it is too big.
Step 7: Seam all four corners fully
Empty corners are usually a seaming problem. Work right into the corner on every side before you close the last edge.
Run the seven steps on a small cover first, such as the Color Block Square, and you will know your own allowance before you commit to a large one. Write it on a sticky note and keep it with the swatch.
If it goes wrong: four ways a cover fails
- It looks flat and saggy. The cover is the same size as the insert or larger. Lay the front panel on the form to check. If it reaches the edges with slack to spare, go up a form size.
- The corners are empty. You stopped the seam short. Unpick and work right into each corner.
- It grew after blocking. Blocking makes the panel bigger. Block before you decide the size, never after.
- The back gaps. An envelope overlap that is too shallow lets the form show. Overlap the back by the extra inch.
Each is cheaper to prevent than to fix. A small file to try again on is the Crochet Pattern Granny Square PDF Video, and crochet blanket borders uses the same gauge sums for edges.
Questions people ask about crochet pillow covers
Should a crochet pillow cover be smaller than the insert?
Yes, by roughly 5 to 10 percent. Crochet stretches, and a cover made to the exact size of the form finishes larger once it is in use.
How do I crochet a pillow cover for beginners?
Start with a square in single or double crochet, work two identical panels to your target width and seam them on three sides. Check the front panel on the form before you close the fourth. A beginner square to start on is the Crochet Pattern Granny Square PDF Video.
How do I crochet a removable pillow cover?
Work an envelope back: two back panels that overlap, with the extra inch as the overlap. You can then take the cover off to wash it.
How do I close a crochet pillow cover?
Seam three sides, put the form in, and close the last edge by hand with a yarn needle. Work right into each corner.
What is the best yarn for crochet pillow covers?
A smooth worsted cotton or acrylic is the easiest to size, because it has predictable give. Chunky yarn has less stretch, so take the smaller reduction.
What is the best crochet stitch for a pillow cover?
Dense stitches such as a waffle or a bobble hold a shape. Open stitches such as granny squares stretch more, so make the cover smaller.
Can you crochet a cushion cover or a pillow case?
Yes. A crochet cushion cover is two panels seamed round a form, and a pillow case is the same with a longer overlap.
How do I make a crochet cushion cover step by step?
Measure the insert, take 5 to 10 percent off, swatch, chain to your width, work two panels, check them on the form and seam all four corners.
How do I wash a crochet pillow?
Take the cover off the form and wash it by hand or on a gentle cycle, then dry it flat. A cover that has been washed may grow, so expect to need the form size up.
What size insert do I need for an 18 inch crochet cover?
A 20 inch form, if the cover genuinely measures 18. Going up one nominal size is the simplest way to fill a cover that was made too big.
Key takeaways
- Make the cover 5 to 10 percent smaller than the insert.
- Only 8 of 24 patterns state both sizes, and their median allowance is zero.
- An 18 inch insert wants a cover of 17.1 to 16.2 inches.
- Check the front panel on the form before you seam.
- For a square to practise on, try the Color Block Square.
