How to Knit a Striped Diagonal Baby Blanket [Free Video Tutorial & Written Pattern!]

There is something deeply satisfying about a project that looks far more complicated than it actually is. A striped diagonal baby blanket is exactly that kind of knit. The bold lines running across the fabric at a 45-degree angle give it a dynamic, modern feel, and the color changes add a playful pop that makes it irresistible in a nursery. But here is the secret: the whole thing is built on one of the simplest techniques in knitting. If you can cast on, knit, and increase and decrease stitches, you can make this blanket.

In this post, you will find everything you need to get started, including a full written pattern, tips for choosing yarn and colors, guidance on how the diagonal construction works, and a link to the free video tutorial. Whether you are a beginner looking for your first blanket project or an experienced knitter wanting something fast and gift-worthy, this is the blanket for you.

Why a Diagonal Baby Blanket?

Before we dive into the pattern, let’s talk about why diagonal construction is so brilliant for a baby blanket specifically.

Most baby blankets are knitted flat, row by row, either from the bottom edge to the top or from side to side. That works perfectly well, but it means you are always knitting the same length of stitches across your needle. With a wide blanket, those rows can start to feel very long toward the middle of the project, and it is easy to lose momentum.

A diagonal blanket starts from a single corner stitch. You increase one stitch at the beginning of every row until you reach half the blanket’s total width, and then you start decreasing at the beginning of every row while continuing to increase on one side, until finally you reach the opposite corner and bind off. The result is a square or rectangle knitted at a 45-degree angle, with every row of knitting running diagonally across the finished fabric.

This structure means the rows start very short, grow gradually to a maximum length, and then shrink back down again. It keeps the project feeling fresh and dynamic. You are always either watching the row count climb or seeing the end come into view. It is deeply motivating, especially for knitters who struggle with the long-middle-slog that many blanket patterns produce.

The diagonal construction also distributes the weight of the knitting differently on your needles and lap, which many knitters find more comfortable for longer sessions.

Materials You Will Need

Yarn

This pattern uses a worsted-weight yarn, which strikes a great balance between speed and a fabric that is soft and substantial without being too heavy for a baby. You will need approximately 800 to 1,000 yards total, divided across however many colors you want to use.

For the two-color stripe version shown in the tutorial, you will need approximately 450 to 500 yards of Color A and 300 to 350 yards of Color B. If you are adding a third stripe color, divide Color B’s yardage between your two contrast shades.

Choose a yarn that is machine washable. Baby items get washed frequently, and a yarn that requires hand-washing is going to frustrate the parents receiving this as a gift. Look for superwash merino, a merino blend, or a high-quality acrylic in a soft baby-friendly formulation. Some excellent options for this project include Paintbox Simply DK (for a slightly lighter fabric), Lion Brand Pound of Love, Cascade 220 Superwash, and Rowan Softyak DK. Just make sure whatever you choose is labeled machine washable and ideally dryer-friendly.

Needles

US size 8 (5mm) circular needles, 32 inches or longer. Even though this is knitted flat, circular needles give you the capacity to hold the full width of the blanket without the stitches crowding off the ends. You can absolutely use straight needles for the smaller sections at the beginning and end of the blanket, but once you hit the full width, you will be grateful for the cord.

Other Supplies

A yarn needle for weaving in ends, scissors, and a tape measure. Stitch markers are optional but useful for marking the center of the row during the decrease section if you want a visual guide.

Gauge

18 stitches and 24 rows = 4 inches in garter stitch on US size 8 needles.

Gauge is less critical for a blanket than it would be for a fitted garment, but it does affect the finished size. Knit a small swatch before you begin and compare it to the gauge listed above. If your gauge is tighter (more stitches per 4 inches), your blanket will be slightly smaller. If your gauge is looser, it will be larger. Adjust your needle size accordingly to land close to the target gauge if the finished size matters to you.

Finished Size

Approximately 30 inches by 30 inches (76 cm by 76 cm). This is a generous lap blanket for a newborn and a comfortable tummy-time blanket for an older baby. It also makes a lovely stroller blanket.

You can easily scale the pattern up or down by adjusting the maximum number of stitches at the blanket’s widest point. Each additional stitch added to the maximum will add approximately half an inch to each side of the finished square.

Understanding the Construction

The whole blanket is worked in garter stitch, which means you knit every single stitch on every row. Garter stitch is one of knitting’s great gifts. It lies completely flat without curling, it is deeply rhythmic and meditative to work, and it produces a textured, ridged fabric that looks beautiful and holds its shape over time.

The diagonal shaping works like this:

Increase Section: On every row, you knit 1, then work a yarn-over followed by knitting to the end. The yarn-over creates a small eyelet that forms the decorative chain running up the left side of the blanket. This increases the stitch count by one on every row. You continue this until you have reached the target number of stitches.

Decrease Section: On every row, you knit 1, work a yarn-over, then knit 2 together to decrease a stitch at the start of the row, then knit to the last 3 stitches, knit 2 together, and knit 1 to decrease at the end. Wait — let’s simplify that. During the decrease section, you are adding one stitch with the yarn-over and removing two stitches with the decreases, which produces a net decrease of one stitch per row. You continue this until you are back down to 3 stitches, then bind off.

This creates the four sides of the square: the two increase edges and the two decrease edges. The yarn-over decorative edge runs along two of the sides and gives the blanket its finished, intentional-looking border.

Stripe Sequence

The stripes in this blanket run diagonally across the fabric because all your rows run diagonally. To create horizontal-looking stripes on the finished piece, you change colors every 10 rows throughout the project. Since each color-change adds a sharp stripe across the diagonal plane of the fabric, the finished result is a series of bold parallel bands running from one corner of the blanket to the other at a 45-degree angle.

Suggested stripe sequence for a two-color blanket:

10 rows in Color A, 10 rows in Color B, repeat throughout the entire project.

For a three-color version, work 10 rows of Color A, 10 rows of Color B, 10 rows of Color C, and repeat.

You can also vary the stripe width for a more relaxed, boho look. Try 8 rows of one color and 16 of another. Or make thick stripes by working 20 rows of each color. The construction accommodates any stripe sequence you choose, so this is a wonderful place to play with color proportions.

When changing colors, cut the yarn and join the new color, leaving a 6-inch tail on each end for weaving in later. If you prefer to carry the yarn up the side rather than cutting it, you can do this for a two-color stripe — just be aware the carried float will be visible along the edge, which can be hidden if you plan to add a crochet or knitted border.

Written Pattern

Abbreviations:

K = Knit
YO = Yarn over
K2tog = Knit 2 together
CO = Cast on
BO = Bind off

Cast On

Using Color A, cast on 3 stitches using a long-tail or knitted cast-on. Any cast-on you like is fine here.

Increase Section

Row 1 (and every row in this section): K1, YO, knit to end of row.

Continue working Row 1 as written on every row, changing colors every 10 rows according to your chosen stripe sequence, until you have 135 stitches on your needle.

Each yarn-over creates one new stitch per row. So it will take you 132 rows to get from your initial 3 stitches to 135 stitches (you add 1 stitch per row, and 132 rows gets you from 3 to 135).

Decrease Section

Row 1 (and every row in this section): K1, YO, K2tog, knit to the last 3 stitches, K2tog, K1.

Continue working this row, changing colors every 10 rows to maintain your stripe sequence, until you have 3 stitches remaining on your needle.

Bind Off

K1, YO, K2tog. You now have 3 stitches. Pass the first stitch over the second, then the second over the third, and pull the tail through the last stitch to secure. Or simply bind off loosely using your preferred method.

Finishing

Weave in all ends carefully using your yarn needle. Because garter stitch has a lot of natural give, weave the tails through several rows in different directions to secure them well — this is especially important with smooth yarns that can slip out over time.

Wet-block the finished blanket by soaking it in cool water for about 20 minutes, gently pressing out the excess moisture in a towel, and laying it flat to dry. Blocking will even out the stitches, open up the yarn-over eyelets along the edges, and give the blanket a more polished, finished appearance. It also softens many yarns significantly.

Tips for Success

Counting your stitches regularly. Since the whole structure depends on increasing and decreasing by exactly one stitch per row, it pays to count your stitches every 10 rows or so. It is much easier to catch and fix a mistake when you notice it a few rows back rather than 40 rows later.

Marking your transition to the decrease section. Place a locking stitch marker or a piece of contrasting yarn through the center stitch of your needle when you hit 135 stitches. This gives you a visual reminder that you are now in the decrease section and helps you keep your stripe sequence aligned on both halves of the blanket.

Managing your yarn ends. A striped blanket with color changes every 10 rows will accumulate a lot of ends. To save yourself a big finishing session, try weaving in each pair of ends as you go, right after the color change. It only takes a minute or two and saves a daunting pile-up at the end.

Keeping your yarn-overs consistent. The YO in both the increase and the decrease sections should be a standard yarn-over — wrap the yarn around the right needle from front to back between two knit stitches. On the following row, knit into the YO through the front loop. If you accidentally twist it, it will close up and not form the eyelet. If your eyelets are inconsistent along the edge, check that you are wrapping the yarn the same direction each time.

Reading your knitting. After a few inches of work, take a moment to look at your piece and understand what you are seeing. The diagonal lines of the stripe changes, the eyelets forming a clean chain up the edges, the increasing width of the rows — once you can read these visual cues in your fabric, you will always know where you are in the pattern even if you set the project down for a while.

Watch the Free Video Tutorial

If you learn better by watching than by reading, the free video tutorial walks you through every step of this pattern from start to finish. You will see how to cast on, how to work the yarn-over increase, how to join new colors, how to transition into the decrease section, and how to bind off cleanly. The video also includes tips on weaving in ends and a short segment on blocking, so you can see exactly what the finished blanket looks like before and after that final step.

The video is beginner-friendly and moves at a comfortable pace, with close-up shots of the needle and yarn so you can see exactly how each stitch is formed. Pause it, rewind it, watch it as many times as you need — it is completely free and yours to use however helps you most.

Gifting This Blanket

A handknitted baby blanket is one of the most personal and lasting gifts you can give a new family. This one photographs beautifully, folds into a satisfying little stack, and looks impressive enough that people will assume you spent far more time on it than you actually did.

For extra presentation impact, choose colors that coordinate with the nursery palette or the family’s style. Deep jewel tones in a superwash merino make an heirloom-quality gift. Soft pastels in a baby-friendly acrylic are practical and sweet. Bold graphic colors — a bright coral with warm cream, or a deep navy with white — give the blanket a modern, design-forward feel that looks stunning in a contemporary nursery.

Tie the finished blanket with a ribbon, tuck in a small note about the fiber content and washing instructions, and you have a gift that a family will reach for again and again throughout their baby’s first years.

Final Thoughts

This striped diagonal baby blanket manages to be approachable enough for a beginner and satisfying enough for an experienced knitter. The construction is logical and almost self-explanatory once you have worked the first 20 rows. The stripe sequence keeps the color work interesting without ever requiring you to juggle two yarns at once. And the finished result — that bold diagonal stripe pattern stretching from corner to corner — looks genuinely striking draped over a crib rail or folded in a basket.

If you make one of these blankets, share it in the comments below or tag us on social media. There is nothing quite like seeing the same pattern come to life in a hundred different color combinations, and every photo that comes in is genuinely inspiring. Happy knitting!