Baby Tank Top (knit) — Sizes Newborn (0–3m), 3–6m, 6–12m, 12–18m, 18–24m

A simple, comfy top-down-style baby tank knit flat as two rectangles (front and back). Clean edges, optional ribbed hem and neat straps picked up at the top. Suitable for DK / light-worsted weight yarn. Worked in stockinette with minimal shaping so it’s fast and beginner-friendly.

Finished measurements

Newborn (0–3m): Chest 16” / 40.5 cm; Finished length (shoulder to hem) ~9” / 23 cm
3–6m: Chest ~18.2” / 46 cm; Length ~10” / 25.5 cm
6–12m: Chest ~20.4” / 51.9 cm; Length ~11” / 28 cm
12–18m: Chest ~21.8” / 55.4 cm; Length ~12” / 30.5 cm
18–24m: Chest ~23.3” / 59.2 cm; Length ~13.5” / 34 cm

Materials

Yarn: DK / light-worsted weight (suggestion: 100% merino or soft acrylic for babies). Gauge assumed: 22 sts = 4” (10 cm) in stockinette. Typical yardage per 100 g skein for DK: approx 225 yd / 205 m. Yarn required (approx): Newborn 125 yd / 115 m (~25 g); 3–6m 150 yd / 137 m (~35 g); 6–12m 200 yd / 183 m (~50 g); 12–18m 225 yd / 206 m (~60 g); 18–24m 250 yd / 229 m (~70 g). Use more for longer straps or trims.
Needles: US 6 (UK 8, 4.0 mm) circular or straight for flat knitting; smaller for rib if desired: US 4 (UK 10, 3.5 mm) optional for crisper 1x1 rib. Also a short 16” / 40 cm circular is handy for small pieces. Note: US, UK (old) and Metric equivalences shown above.
Notions: stitch markers (optional), tapestry needle, measuring tape, waste yarn or stitch holders for finishing (optional), sewing needle for seams.

Gauge

22 sts & 30 rows = 4” / 10 cm in stockinette on US 6 / 4.0 mm needles. Keep gauge and adjust needle size if needed to match these values.

Abbreviations (US)

CO = cast on
BO = bind off
K = knit
P = purl
K2tog = knit 2 together
Pssk = pass slipped stitch over (if used)
st(s) = stitch(es)
K1tbl = knit through back loop (if used for edge neatness)

Notes

Pattern is worked flat as two identical rectangles (back & front), then seamed at sides leaving armholes. Straps are worked last by picking up stitches along top edge and knitting short straps, then sewing strap ends to the back.
Measurements and row counts are approximate; check fit as you go. Rows per inch at listed gauge ~7.5 rows/inch (30 rows / 4”).
Where numbers are given per size they are listed in order: Newborn (0–3m), 3–6m, 6–12m, 12–18m, 18–24m.

Cast-on / stitch counts (each half piece: front or back)

Newborn: CO 44 sts
3–6m: CO 50 sts
6–12m: CO 56 sts
12–18m: CO 60 sts
18–24m: CO 64 sts

These cast-on counts are based on the gauge above and make up the chest widths given in finished measurements. If you prefer a little more or less ease, adjust CO by increments of 4 sts (2 sts each side).

Length planning (rows)

Working rectangle length = total desired length minus strap height. Strap height used here = 2.25” (approx 17 rows). Hem rib = 1” (approx 8 rows). Rows per inch = 7.5 (approx).

Approx rectangle rows (including 1” hem rib) per size (round to nearest whole row): Newborn ~51 rows; 3–6m ~58 rows; 6–12m ~66 rows; 12–18m ~73 rows; 18–24m ~84 rows. Subtract 8 rib rows to get stockinette rows after hem.

Armhole (unseamed) depth to leave at each side when seaming

Newborn: 3.0” (approx 22 rows)
3–6m: 3.25” (approx 24 rows)
6–12m: 3.5” (approx 26 rows)
12–18m: 3.75” (approx 28 rows)
18–24m: 4.0” (approx 30 rows)

Strap sizing (pick-up stitches & length)

Strap width and stitch counts suggested (each strap): Newborn 6 sts; 3–6m 6 sts; 6–12m 7 sts; 12–18m 8 sts; 18–24m 8 sts. Strap length to knit: ~2.25” (approx 16–18 rows). Adjust length as needed to sit nicely on the shoulder.

Pattern - Back (work 2 identical pieces: back & front; front will be finished the same unless you want a lower front neck - optional notes below)

CO the number of stitches for your size onto US 6 / 4.0 mm needles. Example: Newborn CO 44 sts.
Hem rib: Row 1 (RS): *K1, P1* across. Work 8 rows total (approx 1”). End with WS row.
Switch to stockinette (RS: knit; WS: purl). Work stockinette until piece measures rectangle height minus rib to reach top edge (refer to “length planning” rows). For example newborn: after rib, work about 43 more rows of stockinette (total rectangle rows ~51).
When you have completed rectangle rows, BO all stitches loosely. Make a second identical piece.

Seaming

Lay front and back pieces together, RS facing. Seam each side from hem upward using mattress stitch or preferred invisible seam, stopping with armhole depth rows unseamed (see armhole depth rows per size above). The unseamed top portion will become the armhole opening where straps and upper edge finish will be worked.
E.g., for Newborn: seam upward leaving the top 22 rows unseamed; for 3–6m leave 24 rows unseamed, etc.

Straps (worked after seaming)

On the RS, with US 6 / 4.0 mm needle, from front piece top edge mark approximately 1/2” from side seam inward (or visually place the strap about 1/2” in from the side). Between that point and toward center pick up the number of stitches listed for your size, picking them up evenly along the top edge. Example: Newborn pick up 6 sts.
Work the strap flat in garter (all rows knit) or in 1x1 rib to match hem width: - Row 1 (RS): knit to end. - Row 2 (WS): knit. Repeat until strap measures approx 2.25” (about 16–18 rows) or desired shoulder length. For a neater, stronger strap you can work K2, P2 rib instead. BO loosely. Repeat for the other front strap.
On the RS, align each front strap to the back top edge where it will attach (about 1/2” from the side seam on the back). Sew strap ends to the inside of the back with mattress stitch or whipstitch so straps face forward (check that straps are not twisted and that the tank fits). Make sure straps are symmetrical on both sides.

Finishing

Weave in all ends securely. Trim excess.
Optional: Pick up stitches around the neck opening and knit 4” of 1x1 rib and BO loosely to form a neat neckline band. Alternatively, single crochet around the neckline with a US G/6 (4.0 mm) hook for a tidy finish if you crochet.
Block gently to measurements: wet block or steam-block on the wrong side to relax fabric and even stitches. For baby items use low heat and a pressing cloth when steaming.

Front neckline variation (optional)

To create a scoop front neck: before binding off the top edge when finishing the front rectangle, work a shallow neckline by binding off the center N stitches (approx 6–10 sts depending on size) and finish each shoulder separately, decreasing 1 st at the neck edge on 1–2 rows to shape. Alternatively, simply place straps a little closer to the center to visually lower the front neck.

Customizing & sizing tips

To change finished width change CO by multiples of 4 sts (2 sts each side) to keep balance and rib symmetry.
To lengthen, add stockinette rows to the rectangle before binding off.
If your gauge differs, calculate cast-on = (desired chest circumference in inches x gauge sts per inch) / 2 for each half piece.

Care

Follow yarn recommendations. For baby items we recommend gentle machine wash on delicate (if yarn allows) or hand wash and dry flat. Avoid high heat drying.

Troubleshooting & tips

If the armholes are too tight after seaming, reduce the seamed height (sew less up from hem) to leave a larger armhole opening.
For a more secure strap attach, stitch strap ends to an inch-wide panel of the inside of the back using small stitches so they do not come loose with wear.
If you prefer seamless construction: this simple rectangle approach can be adapted to be knit in the round and steeked for armholes (advanced technique; not covered here).

Copyright & support

Pattern by PurlJam. For help or permission requests email team@verde.uk. Visit https://purljam.verde.uk and follow #purljam on socials. If you share finished garments please credit PurlJam and use #purljam. This pattern may be sold as part of a collection but please do not resell the pattern itself verbatim.

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