Striped 3-Button Cardigan for 18 months (Colourspun Pure Cotton DK)

Top-down or set-in construction can both work; this pattern uses simple flat pieces (back, two fronts, two sleeves) with light seaming for a classic, durable toddler cardigan. Worked in DK weight cotton in three colors — Color A is the main color, Colors B and C are contrast stripes.

Sizes & Finished Measurements

Target size: 18 months
Finished chest circumference: 54.5 cm / 21.5 in
Length from shoulder to hem: 29 cm / 11.5 in
Sleeve length from underarm to cuff: 18 cm / 7 in
Upper arm (finished): 24 cm / 9.5 in

Yarn (Colourspun Pure Cotton DK)

Yarn weight: DK / Light (Category 3)
Typical ball: 50 g = 115.5 m / 126 yd per ball (use label on your yarn to confirm exact metreage)
Yarn required (approx): Color A (main): 150 g = ~346.5 m / ~379 yd (approx 3 x 50 g balls). Color B (contrast 1): 50 g = ~115.5 m / ~126 yd (1 x 50 g ball). Color C (contrast 2): 50 g = ~115.5 m / ~126 yd (1 x 50 g ball). Total ~250 g / ~577.5 m (~632 yd).

Needles & Notions

Main needles: 4.00 mm (US 6; approx UK 8 (old)) — straight or 40 cm circular for knitting pieces flat
Smaller needles for ribbing (optional): 3.75 mm (US 5; approx UK 9 (old)) if you prefer firmer ribbing
Tapestry needle, set of stitch markers, stitch holder or scrap yarn, measuring tape, 3 small buttons (approx 12 mm / 1/2 in)

Gauge

22 stitches and 28 rows = 10 cm / 4 in in stockinette stitch on 4.00 mm needles. Check your gauge and adjust needle size if necessary.

Abbreviations

CO = cast on
k = knit
p = purl
st(s) = stitch(es)
RS = right side
WS = wrong side
k2tog = knit 2 together (right-leaning decrease)
ssk = slip, slip, knit (left-leaning decrease)
m1 = make 1 (increase)
BO = bind off

Stripe pattern & notes

This pattern uses repeating stripes. A recommended stripe repeat: 8 rows Color A, 6 rows Color B, 6 rows Color A, 6 rows Color C — repeat as needed. To keep stripes matching across pieces, always change color at the beginning of an RS row and carry floats only a few stitches to avoid puckering. For a softer look, change colors every 6 rows instead of 8.

Construction overview

Work back, two fronts and two sleeves flat. All pieces begin with a 2x2 rib cuff/band worked on smaller needles if desired (3.75 mm), then switch to 4.00 mm for stockinette and striping. Pieces are blocked lightly (cotton relaxes but can be lightly steamed), then seamed. Pick up stitches for the buttonband and sew on buttons.

BACK

Using 3.75 mm needles (or same 4.0 mm if you prefer), CO 60 sts with Color A.
Work 2x2 rib (k2, p2) for 11 rows (approx 4 cm / 1.5 in). Change to 4.00 mm needles.
Begin stripe sequence and work in stockinette (RS: knit, WS: purl) maintaining the chosen stripe repeat. Work until piece measures 18 cm / 7 in from cast-on edge (this includes ribbing). Note: with our gauge this is about 50 rows from CO; because rib is ~11 rows, you'll do ~39 stockinette rows — but measure to match gauge.
Shape armholes: BO 4 sts at beg of next 2 rows (4 sts at each armhole edge). (Remain sts: 52.)
Next row (RS): k1, k2tog, knit to last 3 sts, ssk, k1. Repeat this decrease row every 6th row 3 times (reduce 6 sts total). After these decreases you should have 46 sts remaining. (Adjust spacing if you altered gauge.)
Continue in pattern until armhole measures 12 cm / 4.75 in from the first armhole BO row. Then work shoulder shaping: BO 11 sts at beg of next 2 rows for shoulders (or divide sts to create 3-needle shoulder seam). Place remaining center sts on a holder for the neck if you prefer a shaped back neck; for a simple straight neck BO all remaining sts.

LEFT FRONT (button band on right front when worn — knit as left front so buttons are on left when worn; adjust if you prefer)

CO 30 sts with Color A on 3.75 mm needles.
Work 2x2 rib for 11 rows to match back. Change to 4.00 mm.
Work in stockinette and stripe sequence until piece measures same as back to underarm (18 cm / 7 in from CO).
Shape armhole: BO 4 sts at armhole edge (WS row if you began RS on right side; ensure mirrored shaping to the back). Then dec 1 st at armhole edge every 6th row 3 times (ssk at armhole edge). Keep the neck edge unshaped until shoulders.
When armhole depth equals back (12 cm / 4.75 in) work shoulder shaping to mirror back: BO 11 sts at shoulder edge and leave remaining sts for neck (or BO center neck sts to match back). For a neat button band, do not BO stitches on the front edge — leave or pick up and work band later.

RIGHT FRONT (buttonholes)

Work as Left Front but mirror all shaping so decreases are on opposite sides.
For buttonholes: work three evenly spaced buttonholes into the right front edge band during the buttonband step, or create buttonholes on the right front while working the front: after the rib and once the front is complete and before seaming, mark buttonhole positions. Recommended positions (from neck edge): 1st buttonhole 2.5 cm down from neck edge, then 6.5 cm between buttons (approx). To make a 2-stitch horizontal buttonhole: when you reach the buttonhole position on RS, k to position-2, k2tog, yarn over, continue. On next row purl; the yarn over creates the hole. Adjust spacing to suit your buttons.

SLEEVES (make 2)

CO 44 sts with Color A on 3.75 mm needles.
Work 2x2 rib for 11 rows (cuff), change to 4.00 mm and begin stripe pattern in stockinette.
Increase for sleeve shaping: after rib, increase 1 st each end every 12th row 4 times (m1, knit across, m1) — total +8 sts = 52 sts. (If you prefer a roomier sleeve, increase every 10th row 5 times to reach 54–56 sts.)
Continue in pattern until sleeve measures 18 cm from underarm to cuff (or until sleeve length from cuff to underarm plus seam allowance matches body underarm depth). Alternatively measure against garment back underarm depth.
At sleeve cap shaping (for set-in sleeve): BO 4 sts at beg of next 2 rows, then dec 1 st each side every 6th row 3 times, then BO remaining sts when cap height equals about 7 cm (adjust to match body armhole depth and ease). Put sleeve aside. (Because toddler sizes and tension vary, match to back armhole curve: ease is preferable.)

BUTTONBAND (pick up and work)

With RS facing and 3.75 mm needles, pick up and knit 3 sts for every 4 rows (or pick up evenly) along the right front edge for the buttonhole band to a width of approx 2.5 cm. Work 2x2 rib for the width of band for the length matching front height, creating buttonholes on the right-hand band where marked (or use the buttonhole locations made while knitting the front).
On the left front, pick up stitches and work the same width band in 2x2 rib without buttonholes.
Alternatively you can pick up fewer sts and work a narrower single-rib band (k1, p1) — keep band widths consistent on both sides.

FINISHING

Block pieces lightly to measurements (cotton will relax; do NOT overstretch — gently pin to measured sizes and spray/steam). Let dry completely.
Seam shoulders with mattress stitch or preferred seaming technique.
Set in sleeves easing the cap to fit the armhole; use mattress stitch to seam sleeve seams and side seams.
Sew buttonband edges flat and tidy, then sew on 3 buttons to correspond to buttonholes. Suggested button placement: first button ~2.5 cm from neck edge, subsequent buttons ~6.5 cm apart.
Weave in all ends securely. Cotton can pop ends if not secured — use duplicate stitch or extra neat weaving.

Adjustments & tips

To make the cardigan a little larger/smaller, alter the number of cast-on stitches in multiples to keep the stitch pattern: add or remove 4 sts to the back and 2 sts to each front (keeping the total chest measurement consistent).
If your gauge differs, calculate required cast-on using gauge: desired half-chest = finished chest / 2 = ~27.25 cm; multiply by (stitches per cm) from your gauge (22 sts / 10 cm = 2.2 sts/cm) => ~60 sts for the back.
Keep stripe sequence consistent across pieces by noting the row where each color change happens; take a photo of a color-change row to match on other pieces if necessary.

Care

Colourspun pure cotton DK: machine wash warm or cool depending on yarn label; reshape and dry flat to preserve shape. Cotton will relax when wet — avoid excessive heat.

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