5 Mitered Squares Pillow Cover Free Knitting Pattern

There is something deeply satisfying about a project that is both mathematically elegant and visually stunning. The mitered square is one of knitting’s great pleasures — a technique that uses simple short-row shaping to create fabric that looks complex but knits up in a logical, meditative rhythm. When you combine five of these squares into a single pillow cover, you get a finished object that looks like it belongs in a design boutique, yet costs only a skein or two of yarn and an afternoon or two of your time.

This free knitting pattern will walk you through everything you need to create a gorgeous mitered squares pillow cover from cast-on to finishing. Whether you are new to mitered knitting or already love the technique and want a fresh project to sink your needles into, this pattern is written to be clear, detailed, and completely doable. You will find yarn recommendations, gauge information, step-by-step instructions for each square, and tips for assembling and seaming the finished cover. Let’s dive in.

What Is a Mitered Square?

Before we get to the pattern itself, it helps to understand what a mitered square actually is, because once you grasp the concept, the whole project clicks into place.

A mitered square is a knitted square worked on the diagonal. You cast on stitches along two adjacent sides of the square — essentially a long row of stitches — and then decrease at the center on every right-side row. Those decreases draw the fabric inward at a 45-degree angle, and over time the square folds in on itself until only a few stitches remain. The result is a flat, sturdy square with a decorative diagonal ridge running from corner to corner.

What makes mitered squares addictive is the combination of structure and versatility. Because each square is worked independently, you can use a different color or yarn for each one, creating bold color blocking effects. You can also pick up stitches from the edge of one finished square to start the next, which means the squares connect seamlessly as you knit and there is very little sewing at the end. The five-square arrangement in this pattern creates a shape reminiscent of a plus sign or a simple quilt block, and it works beautifully as a pillow front.

Materials You Will Need

Yarn: Approximately 200 to 250 yards of worsted weight yarn total. This pattern uses two colors — a main color (MC) and a contrast color (CC) — for a classic, graphic look. You can use one color for a more subtle, textured effect, or go wild with five completely different colors for one square each. Good choices include cotton blends for a crisp finish, wool for warmth and stitch definition, or acrylic for easy care. If you want a very durable pillow that holds its shape over years of use, a wool-acrylic blend is an excellent middle ground.

Needles: US size 7 (4.5mm) straight or circular needles, or whichever size gives you the correct gauge.

Notions: Tapestry needle for weaving in ends and seaming, scissors, stitch markers (optional but helpful), a 16-inch pillow insert (or your preferred size — see the sizing note below), and either a zipper, buttons, or a simple envelope back for closure.

Gauge: 18 stitches and 36 rows = 4 inches in garter stitch (knit every row). Gauge is important here because mitered squares are quite sensitive to tension — even a small difference in gauge will change the finished size of your squares significantly. Take the time to knit a swatch and block it before you begin.

Sizing Information

Each individual mitered square in this pattern measures approximately 5.5 inches by 5.5 inches after blocking. The finished five-square arrangement — one center square with four squares attached to each side — creates a cross shape that measures roughly 16.5 inches across and 16.5 inches tall when the squares are joined. This fits a standard 16-inch pillow insert perfectly with a slight amount of ease that helps the cover look full and plump.

If you would like a larger pillow cover, you can simply cast on more stitches for each square. Adding 10 stitches to the cast-on (keeping the center stitch) will increase each square by approximately one inch in each direction, which adds two inches to the overall dimensions of the cover. For a 20-inch pillow, you would work squares with a 70-stitch cast-on instead of the 50-stitch cast-on used in this pattern.

Pattern Notes

Throughout this pattern, stitches are worked in garter stitch, meaning you knit every row on both right-side and wrong-side rows. This creates a reversible, ridged texture that is forgiving and stretchy, making it ideal for pillow covers that will be stuffed and handled regularly.

The center decrease used in this pattern is worked as follows: knit to one stitch before the center stitch, slip two stitches together knitwise, knit one, pass the two slipped stitches over. This is commonly abbreviated as sl2tog-k1-psso or s2kp, and it is a double decrease that removes two stitches at once while keeping the center stitch upright, creating that characteristic clean diagonal ridge.

A stitch marker placed on either side of the center stitch can be very helpful, especially for new mitered square knitters. Place one marker before the center stitch and one after, and you will always know exactly where your decrease falls.

Abbreviations used in this pattern include k (knit), sl2tog-k1-psso or s2kp (double decrease as described above), CO (cast on), BO (bind off), and MC and CC (main color and contrast color).

The Pattern

Square One: The Center Square

Using MC, cast on 51 stitches using your preferred cast-on method. A long-tail cast-on gives a tidy edge, but any cast-on works. Place a stitch marker on either side of stitch 26, which is the center stitch.

Row 1 (Right Side): Knit to one stitch before the first marker, sl2tog-k1-psso (removing the markers and then replacing them on either side of the new center stitch), knit to end. You now have 49 stitches.

Row 2 (Wrong Side): Knit across.

Repeat these two rows, decreasing by two stitches every right-side row, until 3 stitches remain. On the next right side row, work the decrease once more to bring the count to 1 stitch. Cut yarn, pull the tail through the last stitch, and secure.

You have completed Square One. The diagonal ridge runs from one corner to the opposite corner, and the square has four distinct triangular sections divided by that central decrease line.

Block this square gently by wetting it or steaming it and pinning it to your measurements. Let it dry completely before proceeding. Blocking at this stage makes picking up stitches for the adjacent squares much easier.

Square Two: Top Square

With Square One in front of you, identify the top edge — the side that runs from the top-left corner to the top-right corner. You will pick up stitches along this edge to begin Square Two.

Using CC, pick up and knit 25 stitches along the top-left half of Square One’s top edge, then pick up and knit one stitch at the corner (this will become your center stitch), then pick up and knit 25 stitches along the top-right half of the top edge. You will have 51 stitches on your needle.

Place markers on either side of the center stitch and work as for Square One: knit right-side rows with the double decrease at center, knit wrong-side rows plain, until 1 stitch remains. Cut yarn and fasten off.

Square Three: Bottom Square

Rotate your work and identify the bottom edge of Square One. Pick up stitches along this edge just as you did for Square Two, this time using MC.

Pick up and knit 25 stitches along the bottom-left half, 1 center stitch at the corner, and 25 stitches along the bottom-right half. Work exactly as for Square One and Square Two until 1 stitch remains. Fasten off.

Square Four: Left Square

Rotate your work to the left side of Square One. Using CC, pick up and knit 25 stitches along the upper-left edge, 1 center stitch at the left corner of Square One, and 25 stitches along the lower-left edge. Work as established until complete. Fasten off.

Square Five: Right Square

Rotate your work to the right side. Using MC (or CC if you prefer — try holding it up and seeing which appeals to you more), pick up and knit 25 stitches along the upper-right edge, 1 center stitch at the right corner, and 25 stitches along the lower-right edge. Work as established until complete. Fasten off.

Joining the Outer Corners

When all five squares are complete, you will notice that the four outer squares have gaps at their outermost corners where they do not connect to each other. These gaps are a natural result of the cross-shaped layout, and they need to be closed for the pillow to have clean edges.

For each gap, use your tapestry needle and a length of yarn to whipstitch or mattress stitch the two open edges together, matching row for row. Work slowly and try to maintain consistent tension. When blocked, these seams will become nearly invisible, especially in garter stitch.

Making the Pillow Back

The five-square front of your pillow cover is now complete, and it is genuinely beautiful — go ahead and take a moment to admire it. Now it is time to create the back.

You have several options here, and the choice depends on how much time you want to invest and how you prefer your pillow cover to open for washing or for swapping out the insert.

Option 1: Simple Knitted Back. Cast on enough stitches to match the width of your pillow front (approximately 75 stitches in this gauge) and knit in garter stitch until the piece measures the same height as your pillow front. Use the same yarn as your MC for a cohesive look, or use a completely different color since the back will not be visible. Seam the front and back together on three sides, insert the pillow form, and seam the fourth side closed. This is the quickest approach, though it makes removing the pillow insert more difficult if you want to wash the cover.

Option 2: Envelope Back. This is the most popular approach for pillow covers because it allows easy removal of the insert. Knit two rectangular pieces, each approximately 16.5 inches wide and 11 inches tall. When you sew the back to the front, these two pieces overlap at the center of the back by several inches, creating a hidden opening. The insert slips in and out easily, and no buttons or zippers are required.

Option 3: Fabric Back. Choose a cotton or linen fabric in a color that complements your yarn and cut a piece to match the dimensions of your pillow front plus seam allowance. Sew the fabric back to your knitted front by hand using a whipstitch along the edges. This approach is fast if you have fabric on hand and gives a very clean finish. It also adds structure to the back that keeps the pillow’s shape well over time.

Option 4: Button or Zipper Closure. If you want a very polished finished object, a row of three or four buttons along the opening, or a hand-sewn zipper, will keep your pillow cover looking tidy and make washing easy. For a button closure on a knitted back, work a row of yarn-overs and paired decreases near one edge to create buttonholes, then sew buttons to the other overlapping panel.

Assembly and Finishing

Regardless of which back option you choose, the final assembly steps are the same. Pin the front and back pieces together with wrong sides facing outward (or right sides together if you are seaming by hand and want the seam allowance on the inside). Sew around three sides, being careful to keep your tension even and your corners square. Insert the pillow form and close the final side.

Before you close that last seam, take a moment to check that the pillow front is centered and flat. The cross-shaped arrangement of the five squares can occasionally shift if one square was blocked slightly off-square, and it is much easier to adjust before the last seam is sewn than after.

Once the pillow is assembled, weave in any remaining ends on the inside of the cover. Give the entire cover a final blocking or pressing to smooth any remaining puckers or inconsistencies in the knitted fabric. If your yarn is washable, a quick trip through the gentle cycle of your washing machine in a mesh laundry bag can fluff everything up beautifully.

Color and Yarn Inspiration

One of the greatest joys of this pattern is how dramatically different it looks depending on your color choices. Here are a few combinations worth considering.

A two-color version using a deep navy MC and a warm cream CC produces a look that is simultaneously modern and classic, perfect for a living room with neutral furnishings. Reversing those colors — cream as MC and navy as CC — gives a slightly lighter, airier impression.

For a bolder statement, try using a different color for each of the five squares. A palette pulled from a single color family, such as five shades of green ranging from sage to emerald, creates a sophisticated ombre effect. A palette of completely contrasting colors looks like a modern art installation and works well in children’s rooms or eclectic spaces.

If you prefer a more subtle, textural effect, knitting all five squares in the same solid color or in a heathered tweed yarn lets the mitered geometry speak for itself without the distraction of color contrast. This approach photographs beautifully and appeals to people who prefer understated decor.

Variegated or self-striping yarns are worth experimenting with, though they can be unpredictable in mitered squares because the diagonal decrease line interrupts the color pooling in unexpected ways. Sometimes the results are chaotic; sometimes they are surprisingly beautiful. If you have a skein of variegated yarn you have been saving, this is a low-stakes way to see how it behaves.

Tips for Success

If you have never worked mitered squares before, the first square may feel a little awkward as you get used to the rhythm of decreasing every right-side row. By the time you finish the center square, the pattern will feel completely natural, and the remaining four squares — which you work by picking up stitches from the edges of the previous ones — will knit up quickly and with growing confidence.

Pay attention to your tension when picking up stitches along the edges of completed squares. It is easy to pick up too tightly, which can pucker the fabric, or too loosely, which can leave gaps. Aim for one stitch per garter ridge when picking up along the vertical edges, and adjust slightly if the resulting fabric looks uneven.

Block frequently and aggressively. Garter stitch benefits enormously from blocking, and mitered squares in particular flatten out and square up beautifully when wet-blocked. Do not skip this step.

Finally, keep your gauge swatch. If you run out of yarn partway through and need to substitute a new skein, your swatch will tell you whether the new skein knits at the same tension, which can vary slightly even within the same yarn and color.

A Note on Difficulty

This pattern is rated as easy to intermediate. The stitch pattern itself — garter stitch with a central double decrease — is accessible to anyone who can knit and purl and is comfortable with basic decreases. The technique of picking up stitches from the edge of a finished square to begin a new one may be new to some knitters, but it is straightforward once demonstrated, and there are many video tutorials available online if you want to see the technique in action before you begin.

The only aspect of this pattern that requires a little patience is keeping track of the center stitch through many rows of decreasing. Using stitch markers consistently will make this much easier, and after a few repeats you will find that your eye naturally locates the center without needing to count.

Final Thoughts

The five mitered squares pillow cover is one of those rare knitting projects that delivers at every stage. The individual squares are satisfying to complete on their own — small enough to finish in a single sitting, complex enough to feel like an accomplishment. Watching the squares connect and the cross shape emerge is genuinely exciting. And the finished pillow, with its geometric lines and handmade texture, is the kind of thing that people notice and ask about.

Because the pattern uses relatively small amounts of yarn, it is also an ideal stash buster. Check your yarn basket for worsted weight scraps that coordinate and put them to use. You may find that a pillow you had not planned on making becomes one of your favorite finished objects.

Knit this pattern once and you will understand why mitered squares have passionate fans in the knitting community. The rhythm of the decrease, the way the fabric builds on itself, the small triumph of each completed square — it all adds up to