Almohadón Diagonal Free Knitting Pattern: A Complete Step-by-Step Guide
There is something deeply satisfying about knitting a pillow from scratch. You choose the yarn, you feel the texture grow under your hands, and at the end you have something functional, beautiful, and entirely your own. The diagonal pillow — known in Spanish as almohadón diagonal — is one of the most elegant and achievable projects for knitters who want to move beyond scarves and dishcloths without diving headfirst into complex colorwork or intricate lace. The diagonal construction gives the finished fabric a gentle, dynamic slant that looks impressive but is built from a remarkably simple technique: increasing and then decreasing, one stitch at a time.
This guide will walk you through everything you need to know to knit your own diagonal pillow, completely free. Whether you are a beginner who has mastered the knit stitch and wants a next project, or an intermediate knitter looking for a satisfying weekend make, this pattern is designed to be accessible, adaptable, and genuinely enjoyable. You will find materials, gauge information, cast-on instructions, row-by-row guidance, finishing techniques, and plenty of tips to help you customize the project to suit your home.
Why Knit a Diagonal Pillow?
Before getting into the pattern itself, it is worth understanding why the diagonal construction is such a clever choice for a pillow cover.
A standard square or rectangle knitted flat is worked from one horizontal edge to the opposite horizontal edge. The diagonal version starts from a single corner stitch and grows outward, like a square tipping onto one of its points. You increase at the beginning of each row until you have reached the widest point — the center diagonal — and then you decrease at the beginning of each row until you are back to a single stitch. The result is a perfect square of fabric with the knit rows running at a 45-degree angle to the edges.
This diagonal grain does several things for you. First, it gives the fabric a beautiful directional texture even when worked entirely in stockinette or garter stitch. Second, because you are working increases and decreases rather than counting out a specific number of rows, it is very easy to adjust the size simply by knitting more or fewer rows before switching from increasing to decreasing. Third, it is a meditative, rhythmic project — the row lengths gradually grow and then gradually shrink, giving you a natural sense of progress and momentum.
Materials You Will Need
One of the best things about this pattern is that it requires very few materials. Here is what to gather before you begin.
Yarn: For a standard 40 x 40 cm (approximately 16 x 16 inch) pillow insert, you will need roughly 200 to 250 grams of a worsted-weight yarn (also labeled as Aran weight or weight 4 on the standard yarn weight scale). Any fiber works well — wool gives warmth and elasticity, cotton gives structure and a crisp look, and an acrylic or wool-acrylic blend offers durability and easy care. Choose a yarn that has good stitch definition so that the diagonal lines of the fabric show clearly. Avoid very fluffy or heavily textured novelty yarns for your first attempt, as they make it harder to see your stitches.
Needles: A pair of straight needles or a circular needle in the size recommended on your yarn label. For a typical worsted-weight yarn this will be somewhere between 4.5 mm and 5.5 mm. You can also use bamboo or wooden needles if you find that the yarn slides off metal needles too easily.
Additional supplies: A tapestry or blunt-tipped yarn needle for seaming and weaving in ends, a pair of scissors, a tape measure, pins for blocking, and a 40 x 40 cm pillow insert for stuffing.
Optional: If you want to add a button closure or a zipper to the back, you will also need buttons or a zipper in a compatible color, a sewing needle, and thread.
Gauge
Gauge matters more for pillows than it does for dishcloths, because the finished panel needs to fit over your pillow insert. Take a few minutes to knit a gauge swatch before starting.
Cast on 20 stitches and work in your chosen stitch pattern for approximately 20 rows. Block the swatch lightly (wet it, gently press out excess water, and lay it flat to dry), then measure how many stitches and rows fall within a 10 cm (4-inch) square. For a worsted-weight yarn on 5 mm needles, a typical gauge is around 18 stitches and 24 rows per 10 cm in stockinette stitch, though this varies by yarn and individual knitter tension.
Because the diagonal pillow is sized by increasing until the diagonal equals the desired finished measurement rather than by casting on a precise number of stitches, gauge is slightly more forgiving here than in garment knitting. However, knowing your gauge will help you predict how large the finished piece will be and adjust needle size if needed.
Understanding the Construction
The diagonal pillow is worked as two identical square panels. Each panel begins at one corner with a single stitch, increases to the widest diagonal, and then decreases back to a single stitch. The two panels are then seamed together on three sides, the pillow insert is placed inside, and the fourth side is either seamed closed or finished with a button or zipper closure.
Some knitters prefer to make the back panel in a different stitch pattern or color to save yarn and add a design contrast. Others knit both panels identically for a reversible cushion. Both approaches are completely valid — this guide gives you the tools to choose.
The Pattern
Abbreviations
CO — cast on
K — knit
P — purl
K2tog — knit two stitches together (a right-leaning decrease)
KFB — knit into the front and back of the same stitch (an increase that adds one stitch)
BO — bind off
RS — right side
WS — wrong side
Rep — repeat
St(s) — stitch(es)
Stitch Pattern Options
Garter stitch (simplest, recommended for beginners): Knit every row. Garter stitch is reversible, lies flat without curling, and shows the diagonal grain beautifully. It also uses slightly more yarn than stockinette because of its denser row structure.
Stockinette stitch: Knit on right side rows, purl on wrong side rows. Stockinette produces a smooth, classic fabric with excellent stitch definition. Note that stockinette curls at the edges, but since you are seaming all four sides, this does not pose a structural problem.
Seed stitch: Knit one, purl one across every row, alternating the pattern so that knit stitches are purled and purl stitches are knitted on subsequent rows. Seed stitch creates a lovely textured, reversible fabric and lies completely flat.
For the instructions below, the pattern is written in stockinette stitch. Notes on working in garter or seed stitch are included as you go.
Front Panel
Step 1: Start at the corner
Using your chosen needle size, cast on 2 stitches. Leave a tail of approximately 20 cm (8 inches) for seaming later.
Row 1 (RS): KFB, K1. You now have 3 stitches.
Row 2 (WS): KFB, P to last stitch, K1. You now have 4 stitches.
(For garter stitch: KFB, K to end on every row. For seed stitch: KFB, work in seed stitch to end.)
Step 2: Increase section
Continue as established, increasing at the beginning of every row.
Every RS row: KFB, K to end.
Every WS row: KFB, P to last stitch, K1.
(The K1 at the end of WS rows creates a neat selvedge edge that will make seaming easier.)
Repeat these two rows, increasing by one stitch every row, until the diagonal edge of your work — measured from the original cast-on corner along the slanted edge — measures the desired finished size of your pillow. For a 40 cm pillow, the diagonal should measure 40 cm. For a 50 cm pillow, aim for 50 cm. This is typically somewhere between 56 and 72 stitches on the needle, depending on your gauge.
Do not bind off at this point. Mark this row with a stitch marker or a small piece of contrasting yarn to remind yourself where the centerline is.
Step 3: Decrease section
Now you will begin decreasing at the start of every row to bring the stitch count back down to the original corner.
Every RS row: K2tog, K to end.
Every WS row: K2tog, P to last stitch, K1.
(For garter stitch: K2tog, K to end on every row. For seed stitch: K2tog, work in seed stitch to end.)
Continue until 2 stitches remain.
Final row: K2tog. 1 stitch remains.
Cut the yarn, leaving a tail of approximately 20 cm. Draw the yarn through the last stitch and pull to secure.
Back Panel
Repeat all of the above steps to make a second identical square panel. If you prefer a contrasting or plainer back, work this panel in garter stitch or a different color.
Blocking Your Panels
Before seaming, block both panels. This step is especially important with natural fiber yarns like wool, which bloom and relax beautifully with wet blocking. It is also worth doing with cotton, which evens out tension.
Soak the panels in lukewarm water for about 20 minutes, gently press out excess water in a towel (do not wring), and pin them to a blocking mat with the corners squared up and the diagonal edges aligned. Measure as you pin to confirm the panels are the correct size. Allow them to dry completely before removing the pins.
Blocking transforms hand-knitted fabric. Stitches even out, the fabric gains body, and the finished piece looks far more polished.
Seaming the Pillow
Place both panels with wrong sides facing each other. The RS of each panel should face outward. Using the mattress stitch seaming technique and a length of your working yarn threaded on a tapestry needle, seam three of the four sides together. Work along the slanted edges of the square, picking up the horizontal bar between the edge stitch and the next stitch on each panel alternately.
Insert the pillow form through the open fourth side, making sure the corners of the form reach the corners of the knitted cover. Pin the open side closed, check that the pillow looks even and well-stuffed, and then seam the final side closed using the same mattress stitch technique.
Alternatively, leave the fourth side open and finish it with a button band for easier removal when the cover needs washing.
Optional Button Band Closure
To add a simple button band, work as follows on the open edge.
Pick up and knit stitches along the edge of the front panel flap at a rate of approximately 3 stitches for every 4 rows. Work 4 rows in garter stitch. On the fifth row, create buttonholes by working K2tog, YO (yarn over) at evenly spaced intervals — roughly every 8 to 10 stitches, depending on your button size. Work 4 more rows of garter stitch, then bind off. Repeat this band on the corresponding edge of the back panel, omitting the buttonholes. Sew buttons to the back panel band aligned with the buttonholes on the front.
Customization Ideas
Once you understand the basic structure of the diagonal pillow, the design possibilities open up considerably.
Stripes: Because you are working back and forth in rows, adding stripes is simply a matter of changing colors at the start of a new row. Horizontal stripes in the diagonal fabric will appear as diagonal stripes in the finished pillow, which creates a very graphic, modern look. For the most even results, change colors at the beginning of a right-side row and carry the unused color loosely up the selvedge edge.
Texture combinations: The wide central section of the panel provides a wonderful canvas for a panel of textured pattern stitch — a few rows of seed stitch flanked by stockinette, or a simple cable running down the center. Because the center is the widest part of the work, this is where texture is most visible and most impactful.
Color blocking: Work the increase section in one color and the decrease section in another. The color change will follow the diagonal centerline of the pillow perfectly, creating a clean two-tone look.
Size adjustments: To make a larger pillow for a 50 x 50 cm or even 60 x 60 cm insert, simply continue increasing until the diagonal edge measures the new target length. Your stitch count at the centerline will be higher, but the technique is exactly the same. For a smaller bolster or decorative cushion, stop increasing sooner.
Chunky yarn version: For a quicker, cozier knit, this pattern works beautifully in a bulky or super-bulky yarn on 8 mm to 10 mm needles. A chunky diagonal pillow can be completed in a single long evening and makes an excellent gift.
Tips for Success
A few practical notes that will make the process smoother.
Keep a stitch count as you go. Because every increase or decrease row changes your stitch count by exactly one, it is easy to track your progress. Some knitters place a small piece of tape on the needle with the current stitch count written on it, updating it as they go.
Check your diagonal measurement regularly during the increase section rather than waiting until the very end. It is easy to overshoot the centerline, especially once you get into a rhythm.
If you make a mistake and need to rip back a few rows, count your stitches carefully before continuing to confirm you are back to the right number.
Use locking stitch markers to track the centerline row. Placing a marker on the first stitch of the centerline row on both panels will save you time when seaming, because you can align the two markers to confirm the panels match.
When seaming, take your time. A well-seamed pillow looks professional and polished; a rushed seam will draw the eye. If mattress stitch is new to you, practice on a small swatch before working the actual seam.
Finishing and Care
Weave in all yarn ends securely using the tapestry needle, running the tail through several stitches in different directions to prevent it from working loose over time. Trim the ends close to the fabric.
For care, follow the instructions on your yarn label. Most wool yarns benefit from hand-washing in cool water and laying flat to dry. Many acrylic and cotton yarns are machine-washable on a gentle cycle. If your pillow insert is not removable, make sure the knitted cover itself is compatible with the care requirements of the insert.
Frequently Asked Questions
Can I use this pattern with thicker or thinner yarn? Absolutely. The pattern is written in a gauge-agnostic way: you simply increase until the diagonal measures your target size, regardless of yarn weight or needle size. The finished fabric will be denser with thicker yarn and finer with thinner yarn, but the construction works at any scale.
What if my panels come out slightly different sizes? Minor differences can usually be corrected during blocking. Wet both panels, pin them to the same dimensions, and allow them to dry. If one panel is noticeably larger, count your rows in the increase and decrease sections to find where the discrepancy occurred.
Do I need to use a pillow insert, or can I stuff the cover with fiberfill? You can use fiberfill or batting cut to size. However, a proper pillow insert tends to give a more structured, professional result. Loose fiberfill can shift and clump over time.
Can I knit the two panels together in one piece? Yes. An advanced variation involves knitting both panels together and joining them with a three-needle bind off. However, seaming two separate panels gives you more control over the fit and is easier for most knitters.
A Closing Note
The diagonal pillow is a project that rewards patience and rewards presence. There are no complex charts to read, no intricate stitch combinations to memorize. The pattern builds a natural rhythm: increase, increase, increase — until the moment you pivot at the center and begin to decrease. That moment of pivot, when you turn from building to completing, has a pleasing inevitability to it. It feels like the project knowing where it is going.
Knitting your own home accessories is one of the most satisfying things you can do with a set of needles and a ball of yarn. A diagonal pillow is small enough to finish in a reasonable time, large enough to make a real impact on a sofa or bed, and versatile enough that you will want to make more than one. Start with one color, try stripes on the second, experiment with texture
