Free Diagonal Baby Blanket Pattern with Stripes — Knit Any Size!
If you’ve been searching for a baby blanket pattern that looks impressive, works up quickly, and gives you the flexibility to make it any size you want, you’ve landed in the right place. This free diagonal baby blanket pattern with stripes is one of those satisfying knitting projects where the stitch creates the magic. You cast on just a few stitches, work a simple increase-and-decrease method, and watch a gorgeous bias-knit fabric grow before your eyes. Add stripes in two, three, or four colors, and suddenly you have a heirloom-quality baby gift that looks like it took a master knitter to design.
Whether you’re a beginner who just learned to knit or an experienced knitter looking for a mindless but beautiful project to carry to knitting group, this pattern is for you. Let’s walk through everything you need to know, from materials and gauge to step-by-step instructions and tips for customizing the size.
Why Knit a Diagonal Baby Blanket?
The diagonal knit, also called bias knitting, is worked at a 45-degree angle rather than straight across. Instead of working rows from one side of the blanket to the other, you increase along one edge and decrease along another, causing the fabric to grow and shrink on opposing corners. The result is a beautifully draped, slightly stretchy blanket with a distinctive slanted texture that catches the light differently than a traditional garter stitch blanket.
There are several reasons knitters fall in love with this construction:
The stitch pattern is incredibly easy to memorize. Once you understand the logic of “increase one edge, decrease the other,” your hands take over and your mind can wander.
The diagonal bias creates natural stretch and drape, making the blanket cozy for wrapping around a baby without feeling stiff or structured.
Stripes are a breeze to add because you simply change colors at the beginning of a row. No carrying yarn up the side, no complicated color management — just drop one color, pick up another, and knit.
The “knit any size” factor is genuinely achievable. The method described here scales up or down based on how many stitches you cast on and how many increase rows you work before shifting to decreases.
Materials You’ll Need
Yarn: Approximately 400–600 yards of worsted weight yarn in two or more colors. For a standard receiving blanket size (around 30 x 30 inches), plan on roughly 500 yards total across all colors. Baby-safe yarns are always a great choice — look for machine-washable options like superwash wool, cotton blends, or acrylic yarns labeled as soft and hypoallergenic. Popular choices include Lion Brand Pound of Love, Paintbox Simply DK (bumped up a needle size), Cascade 220 Superwash, or any soft worsted you love working with.
Needles: US size 7 (4.5mm) or US size 8 (5.0mm) circular needles, 32 inches or longer. Even though this is knit flat (back and forth), circular needles give you the length you need to hold all those stitches comfortably once the blanket grows to full width. You can also use long straight needles if you prefer.
Notions: Yarn needle for weaving in ends, scissors, stitch markers (optional but helpful), and a tape measure.
Gauge: Approximately 18 stitches and 36 rows = 4 inches in garter stitch on size 8 needles. Gauge matters less than usual for a blanket, so don’t stress if yours is slightly off — just know that a looser gauge will give you a larger, drapier blanket, while a tighter gauge will produce a denser, smaller one.
Abbreviations
k — knit
k2tog — knit two stitches together (a right-leaning decrease)
kfb — knit into the front and back of the same stitch (an increase)
CO — cast on
BO — bind off
RS — right side
WS — wrong side
rep — repeat
st(s) — stitch(es)
Understanding the Construction
Before you dive into the pattern, it helps to understand the three phases of a diagonal blanket:
Phase 1 — Growing: You start with just a few stitches and increase at the beginning of every row. This builds one triangular half of the blanket. The stitch count goes up by one on every row.
Phase 2 — Full Width: Once the blanket has reached its desired width, you stop increasing and start decreasing on one edge while still increasing on the other. This holds the stitch count steady and creates the square body of the blanket. You stay in this phase until the blanket reaches the length you want.
Phase 3 — Shrinking: You decrease on both edges (or rather, you stop increasing and only decrease) to bring the stitch count back down to a few stitches, finishing off the final corner.
This three-phase construction means the blanket is worked as a diamond shape. When you hold it up by one corner, it hangs as a square or rectangle. The finished blanket can be oriented with corners pointing to the sides (diamond display) or rotated 45 degrees to hang flat as a square.
The Pattern
Stripe Color Suggestions
For this pattern, we’ll use two colors: Color A (main color) and Color B (contrast color). A simple stripe sequence to start with is 10 rows of Color A, then 10 rows of Color B, repeating throughout. Feel free to play with stripe widths — thinner stripes of 4–6 rows create a candy-stripe look, while wider stripes of 12–20 rows feel bold and modern. You can also use three or four colors in a repeating sequence. Because stripes are added at the beginning of every right-side row, the color changes are seamless and the yarn ends are easy to weave in along one edge.
Cast On
With Color A, CO 4 stitches.
Phase 1: Increase Section
Setup Row (RS): Kfb, knit to end. (5 sts)
All rows in Phase 1: Kfb, knit to end.
Continue working every row as kfb, knit to end. Change colors according to your chosen stripe sequence. The stitch count increases by 1 stitch on every row.
Keep repeating this increase row until your blanket reaches the desired width. To check width, lay the piece flat and measure across the widest point. For a standard baby blanket (approximately 30 inches wide), continue until you have approximately 135 stitches on your needle, which will be roughly 135 rows of increasing.
Tip for measuring: The diagonal fabric will look like a triangle at this stage. Measure from one side edge to the other across the widest row for your current width.
Phase 2: Straight Section (Body of the Blanket)
Once you’ve reached your desired width, begin the straight section. This is where you work the main body of the blanket, keeping the stitch count constant by increasing on one end and decreasing on the other.
Every row: K2tog, knit to last stitch, kfb.
That’s it. Every single row in Phase 2 is k2tog at the beginning and kfb at the end. The stitch count stays the same, and the fabric grows as a parallelogram. Continue this until the blanket reaches your desired length (measuring along one of the straight edges). For a square blanket, the length of Phase 2 should roughly equal the width you built up in Phase 1.
Continue changing colors every 10 rows (or whatever your chosen stripe interval is) throughout this phase.
Making it a rectangle: If you want a slightly longer rectangular blanket rather than a square, simply work more rows in Phase 2 before moving on to Phase 3.
Phase 3: Decrease Section
Once the blanket body is as long as you want it, begin the decrease section. This mirrors Phase 1 in reverse, bringing the stitch count back down to the final corner.
Every row: K2tog, knit to end.
Repeat this row, decreasing by 1 stitch every row, until 4 stitches remain.
Continue your stripe sequence through to the very end for a polished, finished look.
Bind Off
With 4 stitches remaining, bind off all stitches loosely. Cut yarn, leaving a 6-inch tail.
Finishing
Weave in all ends using a yarn needle, working the tails in along the edges where they’re least visible. Since stripes create color-change ends along the same edge throughout the blanket, you’ll find that most ends live along one straight side. Weave them in carefully and snip close.
Block the finished blanket by soaking it in cool water, gently pressing out excess moisture in a towel, and laying flat to dry. Blocking evens out stitches, opens up the fabric beautifully, and makes a dramatic difference in the finished appearance. For acrylic yarns, you can wet block lightly or use a steamer held several inches away from the surface.
How to Knit This Any Size
This is one of the most versatile aspects of the diagonal blanket construction. Here’s a quick reference for adjusting the size:
For a small lovey or security blanket (approximately 14 x 14 inches), work Phase 1 until you have about 63 stitches, then work Phase 2 for approximately 63 rows, then work Phase 3 to finish. You’ll use roughly 150–200 yards total.
For a standard baby blanket (approximately 30 x 30 inches), work Phase 1 until you have about 135 stitches, work Phase 2 for approximately 135 rows, then finish with Phase 3. Plan on 400–600 yards total.
For a toddler blanket (approximately 36 x 36 inches), work Phase 1 until you have about 162 stitches, work Phase 2 for approximately 162 rows, and finish with Phase 3. You’ll need approximately 700–900 yards.
For a lap blanket (approximately 40 x 50 inches), work Phase 1 until you have about 180 stitches, work Phase 2 for approximately 225 rows, then finish Phase 3. Plan on 900–1,200 yards.
The beauty of this system is that you can cast on and begin without committing to a fixed size. Knit until it’s as wide as you want, then switch to Phase 2, and keep going until it’s as long as you want. The blanket tells you when it’s done.
Stripe Variation Ideas
Stripes transform the look of this blanket completely depending on color and width choices. Here are a few stripe combinations that work beautifully on a diagonal background:
Classic nautical: Deep navy and crisp white in 10-row alternating stripes. Timeless and gender-neutral.
Soft rainbow: Cycle through six pastel shades (lavender, baby blue, soft yellow, mint, blush, peach) in 8-row stripes, repeating the sequence. The diagonal stitch makes the colors pop in an unexpected way.
Modern minimal: A natural cream as the main color with a single bold stripe of terracotta or sage every 20 rows. Simple, modern, and stylish for nursery décor.
Gender-neutral earth tones: Warm taupe, dusty rose, and ivory cycling in 12-row stripes. Perfect for a baby shower gift when you don’t know the gender.
High contrast bold: Charcoal gray and bright mustard yellow in 6-row stripes. Striking and unexpected — this one photographs beautifully.
Because the diagonal stitch naturally creates a slanted line, stripes running across those diagonal rows create a chevron-like or parallelogram effect rather than perfectly straight horizontal bands. It’s one of those happy accidents of construction that makes this blanket look far more complex than it actually is.
Tips for Success
Carry unused yarn loosely up the side of the work when working two-color stripes in small intervals of 4–6 rows. For larger stripe intervals of 10 or more rows, cut the yarn and rejoin to avoid tangling.
Place a stitch marker after the first stitch (after the kfb) in Phase 1, or before the last stitch in Phase 2, to help you remember where your increase or decrease falls. Once the rhythm is in your hands you won’t need it, but it helps at the beginning.
If you lose your place and aren’t sure whether you’re in Phase 1, Phase 2, or Phase 3, count your stitches and compare to where you expected to be. In Phase 1, the count goes up every row. In Phase 2, the count stays constant. In Phase 3, the count goes down every row.
Use a stretchy cast on like the long-tail cast on to keep the starting corner flexible. A tight cast on at the corner can pucker.
Bind off loosely. A tight bind off will cause the final corner to curl or pucker. If you tend to bind off tightly, go up a needle size for the bind off row.
If you want a border, the bias construction already creates a naturally tidy edge. But if you’d like to add a simple crochet border or a picked-up knit border in a contrast color, the garter stitch edge accepts it beautifully.
Yarn Quantity Planning
Running out of yarn mid-blanket is the most common frustration with any project. For this pattern, here’s how to plan:
Weigh your yarn in grams at the beginning of Phase 2. Divide your total yarn weight (including all skeins you plan to use) into the total number of rows you need to complete the blanket. This gives you a rough grams-per-row average. Weigh your work periodically to track whether you’re on pace.
If you’re using multiple colors in stripes, distribute the yarn weight roughly according to how many rows each color appears in. Equal-width stripes mean equal yarn distribution across colors.
Always buy slightly more yarn than you think you need. Dye lots matter with yarn, and running short in the final phase of a blanket is heartbreaking. One extra skein of each color, returned if unused, is well worth the peace of mind.
Making It a Gift
A handknit baby blanket is one of the most meaningful gifts you can give to a new family. The time and care that goes into every stitch communicates something that no store-bought item can. If you’re making this as a gift, consider personalizing the color choices to match the nursery, or choosing colors that reflect something meaningful about the family — a sports team, a favorite flower, the colors of the sea if they live near the coast.
You can also add a small label to the finished blanket. Handwritten tags that say “handmade with love by [your name]” tucked into the corner of the blanket are a lovely touch that new parents often save for years.
A diagonal baby blanket in garter stitch is also a wonderful project for charity knitting. Many hospitals, shelters, and nonprofits accept handknit baby blankets, and this simple-to-scale pattern means you can adjust to whatever size the organization requests.
Final Thoughts
This free diagonal baby blanket pattern with stripes is the kind of project that earns a permanent place in your knitting rotation. It’s simple enough to pick up after a long day when your brain is tired, but the results are beautiful and satisfying enough to give as a treasured handmade gift. The any-size flexibility means you’ll use this method again and again, whether you’re making a tiny lovey for a newborn or a generous lap blanket for a toddler.
Pin this pattern, bookmark it, share it with your knitting group — and most of all, enjoy the knitting. There’s something deeply meditative about the rhythm of this blanket: kfb, knit across, k2tog, knit across. Row after row, color after color, corner by corner, until a beautiful diagonal-striped blanket takes shape in your hands.
Happy knitting!
