Looking for the perfect handmade baby gift that looks impressive but uses classic techniques? This rainbow granny square baby cardigan is exactly what you need. Built entirely from traditional granny squares in soft pastel colors, this little sweater works up into a cheerful, cozy layer for babies aged 6 to 12 months.
The construction is straightforward once you understand the assembly sequence. You will make individual granny squares, join them into panels, seam the body and sleeves, then add ribbed borders and colorful buttons. If you have crocheted a granny square before, you already know the main stitch pattern.
This cardigan makes an unforgettable baby shower gift or a keepsake for your own little one. The pastel rainbow colorway against crisp white borders gives it that modern handmade look that parents love. Let me walk you through everything you need to know.
About This Crochet Pattern
This baby cardigan uses the join as you go method (often called JAYG) to connect classic granny squares into flat panels. The body is worked as three separate panels: one back panel and two front panels. Sleeves are formed from joined squares seamed into tubes. Ribbed borders at the hem, cuffs, and button bands finish the garment with a polished look.
The design includes a small white patch pocket on the lower left front and four colorful buttons down the center. The round neckline sits comfortably without complicated shaping because all the fit comes from the architectural layout of the squares themselves.
Skill Level: Intermediate
You should be comfortable working standard granny squares, joining squares together, seaming, working in the round, picking up stitches for borders, and sewing on buttons. No advanced shaping is required within the squares themselves. The assembly sequence demands careful organization and counting, but each individual step is manageable.
Time Estimate: Approximately 15 to 20 hours for an experienced crocheter. If this is your first time using the join as you go method, add 3 to 5 hours.
Finished Measurements
Size: 6 to 12 months
I have included sizing notes at the end of this pattern for 0 to 3 months and 12 to 18 months.
Materials Needed for This Baby Cardigan
Yarn
Approximately 550 yards / 503 m of DK weight yarn (CYCA 3) total, divided as follows:
Yarn Suggestions
1. Lion Brand Pound of Love (100% premium acrylic, 1020 yards per 16 oz skein): Machine washable and widely available in white. Pair with Lion Brand Baby Soft for the pastels.
2. Paintbox Yarns Simply DK (100% acrylic, 137 yards per 50 g): Available in an extensive palette of soft pastels that match the colorway precisely. One skein each of white plus five pastel shades will cover the full project.
3. Drops Safran (70% cotton, 30% linen, 175 yards per 50 g): For a breathable warm-weather version. Note that cotton has less elasticity, so your gauge swatch is especially important.
Any smooth DK weight yarn that achieves gauge may be substituted. Avoid heavily textured or fluffy yarns because the granny square structure relies on clean stitch definition. Choose machine-washable fiber for a baby garment.
Hook
US size G-6 / 4.0 mm (adjust as needed to meet gauge)
Notions
Gauge
One completed and blocked granny square = 3 in x 3 in / 7.5 cm x 7.5 cm
In single crochet rib (for borders): 18 sts x 22 rows = 4 in / 10 cm
Gauge is mandatory for this garment. The finished chest measurement is directly determined by the number and size of squares. A square that measures 3.25 in instead of 3 in will add over an inch to the chest per column of squares. Swatch, block, and measure before beginning.
Abbreviations
Special Stitches and Techniques
The Classic Granny Square
This cardigan uses a traditional four-corner granny square with three-double-crochet clusters separated by chain-two corner spaces. Each round begins with a slip stitch join and ch-3 standing as first dc.
Round 1 (Color A): Make a magic ring or ch 4 and join with sl st to form a ring. Ch 3 (counts as first dc now and throughout), work 2 dc into ring, ch 2, (3 dc into ring, ch 2) 3 times, join with sl st to top of beginning ch-3. Fasten off. (4 clusters of 3 dc, 4 ch-2 corner spaces)
Round 2 (Color B): Join new color with sl st in any ch-2 corner sp. Ch 3, work 2 dc in same corner sp, ch 2, 3 dc in same corner sp (first corner made), ch 1, (3 dc, ch 2, 3 dc) in next ch-2 corner sp, ch 1. Rep from ( to ) 2 more times, join with sl st to top of beginning ch-3. Fasten off. (8 clusters of 3 dc, 4 ch-2 corner spaces, 4 ch-1 side spaces)
Round 3 (Color C): Join new color with sl st in any ch-2 corner sp. Ch 3, work 2 dc in same corner sp, ch 2, 3 dc in same corner sp (corner made), ch 1, 3 dc in next ch-1 sp, ch 1, (3 dc, ch 2, 3 dc) in next ch-2 corner sp, ch 1, 3 dc in next ch-1 sp, ch 1. Rep from ( to ) 2 more times, join with sl st to top of beginning ch-3. Fasten off. (12 clusters of 3 dc, 4 ch-2 corner spaces, 8 ch-1 side spaces)
Round 4 (MC, White): Join MC with sl st in any ch-2 corner sp. Ch 1, (sc, ch 2, sc) in corner sp (corner made), sc in each dc and in each ch-1 sp across to next corner, (sc, ch 2, sc) in corner sp. Rep around all 4 sides, join with sl st to first sc. Fasten off. (Each side has 11 sc plus 2 corner sc for a total of 52 sc and 4 ch-2 corner spaces)
The white Round 4 creates the clean white border visible between every square in the finished garment.
Join As You Go (JAYG) Method
When adding a new square adjacent to an existing one, work Rounds 1 through 3 of the new square as normal. On Round 4 (MC), work the joining side(s) as follows:
At each joining corner, work (sc, ch 1, sl st into corresponding corner ch-2 sp of neighbor square, ch 1, sc) instead of (sc, ch 2, sc).
Along each joining edge, replace each ch-1 sp between sc groups with sl st into the corresponding sc of the neighbor square.
Continue Round 4 normally on all non-joining sides. This creates a flat, invisible join.
Single Crochet Rib
This technique creates a stretchy, neat border. The rib direction runs perpendicular to the garment edge.
Ch to desired length plus 1.
Foundation row: Sc in 2nd ch from hook and in each ch across. Turn.
Rib row: Ch 1, sc in blo of each st across. Turn.
Rep Rib row for desired length.
Color Sequence for Squares
Each square uses three rounds of two or three contrast colors progressing through the pastels, finished with one round of white. To achieve the rainbow scatter effect, follow these suggested center-to-outer color pairings:
Distribute types so no two identical squares are adjacent. I like to lay out all my squares before joining to make sure the colors are nicely scattered.
Granny Squares Required
Make the following number of squares and organize them by panel before joining:
Total squares: 37
Step by Step Instructions
Making Individual Squares
Work all 37 squares following the Granny Square instructions above. For each square, select a color type (A through F) and record the type so panels can be laid out with variety. The single MC pocket square is worked with MC in Rounds 1 through 4 (all white).
Each completed blocked square = 3 in x 3 in / 7.5 cm x 7.5 cm.
Back Panel Assembly
Lay 12 squares in a 4-wide by 3-tall grid. Vary color types so no two identical squares are adjacent. Using JAYG on Round 4, join squares in rows from bottom to top, left to right.
Row 1 (bottom): Join 4 squares side by side. (4 squares joined horizontally)
Row 2 (middle): Join 4 squares side by side, then join the row to Row 1. (8 squares total)
Row 3 (top): Join 4 squares side by side, then join to Row 2. (12 squares total)
Completed back panel dimensions: 12 in wide x 9 in tall / 30.5 cm x 23 cm
Front Panels Assembly
Right front panel: Join 2 squares wide by 3 squares tall using JAYG. (6 squares)
Completed right front dimensions: 6 in wide x 9 in tall / 15 cm x 23 cm
Left front panel: Join 2 squares wide by 3 squares tall using JAYG. (6 squares)
Completed left front dimensions: 6 in wide x 9 in tall / 15 cm x 23 cm
Shoulder and Side Seaming
Lay back panel flat, RS up. Place right front panel RS up at right side, aligning top and side edges. Place left front panel RS up at left side.
Side seams: With MC and yarn needle, whipstitch or sl-st seam the right side edge of the right front to the right side edge of the back, matching square edges, from hem upward for 9 in (the full height). Repeat for the left front to the left side of the back.
Shoulder seams: The back neckline width is 6 in (center 2 squares of the top row). The back shoulder width on each side is 3 in (1 square on each outer edge of top row).
Seam right shoulder: Join the outer 3 in of the right front top edge to the outer 3 in of the back right top edge. (1 square width seamed)
Seam left shoulder: Join the outer 3 in of the left front top edge to the outer 3 in of the back left top edge. (1 square width seamed)
The neckline opening remaining is approximately 12 in / 30.5 cm circumference.
Sleeve Panels and Assembly
Work two sleeve panels, each 2 squares wide by 3 squares tall (6 squares each). Follow the same JAYG process as for the body panels.
Each sleeve panel: 6 in wide x 9 in tall / 15 cm x 23 cm
Seaming the sleeve tube: Fold one sleeve panel in half lengthwise (so the 9-in edges meet). With MC, seam the long edge (the underarm seam) to create a tube. The tube will have a 6-in circumference, which is perfect for a baby’s upper arm with ease.
Repeat for second sleeve.
Sleeve Attachment
Pin sleeve tube into armhole opening, RS together, matching the sleeve underarm seam to the body side seam. The sleeve tube top edge (the 6-in circumference) is sewn to the 6-in straight edge of the armhole opening.
Because the armhole opening is straight rather than curved, ease the sleeve cap evenly around the armhole, distributing any fullness at the shoulder seam point. Whipstitch or sl-st seam all the way around the armhole for both sleeves.
Neckline Border
With RS facing, join MC with sl st at the right front top inner corner of neckline.
Round 1: Ch 1, work sc evenly around the entire neckline opening as follows: 11 sc across the top edge of the right front inner square, 1 sc in each corner, 22 sc across back neckline (2 squares), 1 sc in each corner, 11 sc across the top edge of the left front inner square, join with sl st to first sc. Do not fasten off. (Approximately 50 sc around neckline; adjust by 1 to 2 sts as needed for a smooth round)
Round 2: Ch 1, sc in each sc around, join with sl st to first sc. Fasten off MC. (50 sc)
Button Band (Right Front)
The button band is worked perpendicular to the front edge in single crochet rib.
Ch 7.
Foundation row: Sc in 2nd ch from hook and in each ch across. Turn. (6 sc)
Rib row: Ch 1, sc in blo of each st across. Turn. (6 sc)
Rep Rib row until band measures 9 in / 23 cm (approximately 40 rows).
Fasten off.
With MC and yarn needle, seam the long edge of the button band to the right front edge of the garment, RS facing out.
Mark button positions: Place 4 button markers evenly spaced along the button band. Position the first button 0.5 in from the top edge and the last button 0.5 in from the bottom edge. Space the remaining 2 buttons evenly between (approximately every 2.5 in).
Sew buttons to band at each marker using needle and thread.
Buttonhole Band (Left Front)
Make buttonhole band in the same rib as button band but add buttonholes.
Ch 7.
Foundation row: Sc in 2nd ch from hook and in each ch across. Turn. (6 sc)
Rib rows 1 through 3: Ch 1, sc in blo of each st across. Turn. (6 sc)
Work rib rows, pausing at each buttonhole position (determined by measuring your button band and marking the same intervals):
Buttonhole row: Ch 1, sc blo in 2 sts, ch 2, sk 2 sts, sc blo in 2 sts. Turn. (4 sc, 1 ch-2 sp)
Next row: Ch 1, sc blo in 2 sts, 2 sc in ch-2 sp, sc blo in 2 sts. Turn. (6 sc)
Continue rib rows between buttonhole rows, repeating until all 4 buttonholes are worked and band measures 9 in / 23 cm total.
Fasten off and seam to the left front edge.
Hem Border
With RS facing, join MC at the lower right corner of the back hem edge.
Row 1: Ch 1, work 1 sc in each st along the entire bottom edge of the joined body (across back and both fronts, including button band edges). (Approximately 100 sc; adjust as needed for a flat edge)
Turn.
Work single crochet rib (blo) for 6 rows. Fasten off. (Hem depth approximately 1.5 in / 3.8 cm)
Cuffs
Each cuff is worked directly from the bottom edge of the sleeve tube.
With RS facing, join MC with sl st at the underarm seam of one sleeve, at the bottom edge.
Round 1: Ch 1, work 1 sc in each sc around the bottom of the sleeve tube edge. Work any needed decreases to achieve a multiple of 2 for rib. Aim for 40 sc. Join with sl st. (40 sc)
Round 2: Ch 1, (sc blo, sc flo) around, join with sl st. (40 sts)
Rounds 3 through 8: Ch 1, (sc blo, sc flo) around, join with sl st. (40 sts)
Fasten off after Round 8. Cuff depth approximately 1.5 in / 3.8 cm.
Repeat for second cuff.
Position the all-white pocket square on the lower left front panel, centered on one square. Pin in place.
With MC and yarn needle, whipstitch the bottom and two side edges of the pocket square to the front panel, leaving the top edge open.
Work 1 row of sc along the top open edge of the pocket for a neat finish. Fasten off.
Finishing Your Cardigan
Weave in all ends securely, especially ends from color changes within each square.
Check that all button and buttonhole placements align correctly. Sew buttons on firmly.
Blocking
Wet block the finished garment by submerging in cool water, gently squeezing out excess (do not wring), laying flat on blocking mats, and pinning to these measurements:
Allow to dry completely before removing pins or wearing.
Care Instructions
Machine wash on gentle cycle with cold water, or hand wash in cool water with mild detergent. Lay flat to dry. Do not tumble dry if using a cotton or linen blend. For acrylic yarns, laying flat is still recommended to preserve the garment’s shape. Do not iron directly on the granny squares. Light steam blocking once the garment is dry can refresh the shape after multiple washes.
Size Customization Tips
To size down to 0 to 3 months: Reduce each panel by 1 row of squares. Body panels become 4 wide x 2 tall (back) and 2 wide x 2 tall (each front). Sleeve panels become 2 wide x 2 tall. Total squares: 25. Chest circumference becomes approximately 16 in / 40.5 cm.
To size up to 12 to 18 months: Add 1 row of squares to the height of all body panels, or add 1 column to the back. For a chest of approximately 22 in / 56 cm, extend the hem to 2 in and adjust button bands to match.
To resize for a different gauge: If your square measures 3.5 in instead of 3 in, adjust the number of squares per row accordingly.
Pattern Notes and Tips
All squares are made individually through Round 3 and joined on Round 4 using JAYG. You can also make them fully and whipstitch with MC if you prefer, but the JAYG method gives the cleanest result.
Block each panel before seaming for best results. The ch-3 at the start of each granny square round counts as the first dc throughout.
Right and left fronts are mirror images. Button loops are made in the button band, not in the squares.
Thank you so much for choosing this pattern. I hope you love making this sweet little cardigan as much as I loved designing it. If you make one, I would absolutely love to see it! Tag me on Instagram or share a photo in our Facebook group. Your colorway choices always inspire me.
If you found this rainbow granny square baby cardigan crochet pattern helpful, save it to your Pinterest boards so you can find it when you are ready to start. And please drop a comment below if you make one. I read every single comment and love hearing about your projects!
