Random Stripe V-Neck Slip-On Vest with Buttonfly Side Splits

Description

A relaxed, layerable slip-on vest featuring a V-neck, generative random stripes in one main color plus five contrast colors, and open side splits secured with a buttonfly placket. Worked flat in two panels (back and front), seamed at the shoulders and upper sides, with the lower sides left open and closed by overlapping button plackets. The random striping gives every garment a unique look while the buttonfly splits add a tailored, sporty detail. Advanced level due to colorwork management, V-neck shaping, and dual placket construction.

Sizes

Written for size M, with adjustments for XS (S, M, L, XL, 2XL).

Sample shown in size M. Instructions below are written for size M with all final numbers spelled out. Where sizes differ, follow the table above and the size-tagged notes.

Materials

• Yarn: Worsted weight (medium / #4), approx. 220 yds/100 g per skein.
  • MC (background): 2 (2, 3, 3, 3, 4) skeins — ~450 (500, 550, 620, 680, 740) yds
  • CC1–CC5 (contrast stripes): 1 skein each color — ~110 yds each per color total (used at random)
• Needles:
  • US 8 / 5 mm straight or circular (for body)
  • US 6 / 4 mm straight or circular (for ribbing and plackets)
• Notions:
  • 8 buttons, 3/4" (19 mm) — 4 per side split
  • Stitch markers, stitch holders/waste yarn
  • Tapestry needle
  • Removable markers for stripe tracking

Gauge

18 sts × 24 rows = 4" (10 cm) in stockinette on US 8 / 5 mm, blocked.

• 4.5 sts per inch; 6 rows per inch.
• Take gauge seriously — fit and placket alignment depend on it.

Abbreviations

• k – knit
• p – purl
• st(s) – stitch(es)
• RS / WS – right side / wrong side
• k2tog – knit 2 together (right-leaning dec)
• ssk – slip, slip, knit (left-leaning dec)
• yo – yarn over
• BO – bind off
• CO – cast on
• rep – repeat
• MC / CC – main color / contrast color
• beg – beginning
• rem – remaining
• pm – place marker

Pattern Notes

Random Stripe Method

1. Assign each color a number: MC = 0, CC1 = 1 … CC5 = 5.
2. Work in stockinette. Use MC as the dominant background — roughly 60% of rows.
3. For contrast stripes, use a random generator (dice, app, or shuffled cards) to select a CC and a stripe height of 2, 4, or 6 rows.
4. Carry rule: Carry unused colors loosely up the side edge; twist every 4 rows. Never carry a color more than 6 rows unworked — cut and rejoin if longer.
5. Match front & back: Record your stripe sequence on the back, then repeat the same sequence on the front so stripes align at the side seams. This is essential for a professional finish.

Construction

• Worked flat in two panels, seamed at shoulders and upper side seams only.
• Lower 5" of each side is left open (split) and closed with an overlapping buttonfly placket: back panel carries the button band (buttons), front panel carries the buttonhole band.
• Slip-on: no full front opening — the V-neck and side splits provide the ease needed to pull the vest on.

Selvedge

Work the first and last stitch of every row as a knit stitch (garter selvedge) for tidy seaming; these are not counted in shaping unless noted.

BACK PANEL

Ribbing

With US 6 / 4 mm and MC, CO 90 sts. Row 1 (RS): k1, *k1, p1; rep from * to last st, k1. Row 2 (WS): k1, *p1, k1; rep from * to last st, k1. Rep Rows 1–2 for 2" (12 rows), ending with a WS row.

Lower Body with Side Splits

Switch to US 8 / 5 mm and begin the random stripe pattern in stockinette (k on RS, p on WS), keeping garter selvedge sts.

Work even in stripe pattern for the split section = 5" (30 rows).

The side edges here will later receive the plackets; keep selvedges neat. Stitch count remains 90 sts.

Upper Body (side seams sewn later)

Continue even in stripe pattern until piece measures 15.5" (94 rows) from cast-on, ending with a WS row.

• Math check: 2" rib (12 rows) + remaining body to armhole. 15.5" × 6 = 93 → worked as 94 rows (even, ends on WS). ✓
• Sts on needle: 90.

Armhole Shaping

BO 4 sts at beg of next 2 rows → 90 − 8 = 82 sts. Dec row (RS): k1, ssk, work to last 3 sts, k2tog, k1. (2 sts dec) Rep Dec row every RS row 5 times total → 82 − 10 = 72 sts. Work even in stripe pattern until armhole measures 8.5" (51 rows from first bind-off), ending with a WS row.

• Armhole check: 8.5" × 6 = 51 rows. ✓

Back Neck & Shoulders

BO all 72 sts loosely (shoulders will be joined to front).

• Distribution reserved for seaming: 22 sts right shoulder + 28 sts back neck + 22 sts left shoulder = 72. ✓

FRONT PANEL

Ribbing, Lower Body & Upper Body

Work identically to the Back — including the same recorded stripe sequence — through the Armhole Shaping. After armhole shaping you will have 72 sts, and armhole should measure 0" at this point (shaping just complete). Continue as follows for the V-neck.

Important: Begin the V-neck at the same row you complete armhole decreases, so the neck point sits centered and shoulders finish level with the back.

V-Neck Shaping

With 72 sts, place a marker at center. Work to center; join a second ball of yarn (and second set of CC as needed) to work both sides at once.

Divide row (RS): Work 36 sts, turn — leave rem 36 sts on holder for the second side.

• 36 + 36 = 72. ✓

Work each side separately. On the neck edge, decrease as follows: Neck dec row (RS, right shoulder side): work to last 3 sts, k2tog, k1. Neck dec row (RS, left shoulder side): k1, ssk, work to end.

Decrease 1 st at neck edge every RS row 14 times → 36 − 14 = 22 sts each shoulder.

• V-neck depth: 14 dec over 28 rows = 4.67" of shaping; continue even to reach full armhole depth.

Work even (no more neck decs) until armhole measures 8.5" (51 rows) to match the back, ending with a WS row.

• Each shoulder: 22 sts. ✓ (matches back shoulder 22 sts)

BO 22 sts each shoulder loosely.

• Front total bound off: 22 + 22 = 44 sts; center 28 sts consumed by V-neck decreases and split (14 dec per side × 2 = 28). 44 + 28 = 72. ✓

SIDE PLACKETS (Buttonfly Splits)

Each side split is 5" (30 rows) tall, worked on the selvedge edges of the lower body sections.

Button Band (Back panel edges — both sides)

With US 6 / 4 mm and MC, RS facing, pick up and knit 1 st in each selvedge row along the split = 30 sts. Work 6 rows in k1, p1 rib (band width ~1.25"). BO in pattern. Repeat for the second side of the back.

Buttonhole Band (Front panel edges — both sides)

With US 6 / 4 mm and MC, RS facing, pick up and knit 30 sts along the front split edge. Work 2 rows in k1, p1 rib. Buttonhole row (RS): rib 3, *yo, k2tog, rib 5; rep from * 3 more times, rib to end.

• 4 buttonholes evenly spaced: positions after sts 3, 10, 17, 24. Spacing ≈ every 7 sts/rows. ✓ Work 3 rows even in rib. BO in pattern. Repeat for the second side of the front.

The front buttonhole band overlaps the back button band. Sew buttons on the back band aligned to the buttonholes: 4 buttons per side, 8 total. ✓

FINISHING

1. Block all pieces to measurements. Blocking evens out the random stripes and relaxes carried floats.
2. Shoulder seams: With MC and mattress stitch, join front and back at each shoulder (22 sts each).
3. Upper side seams: Beginning at the top of each split (5" from cast-on) up to the armhole, seam front to back with mattress stitch. Leave the lower 5" open for the plackets.
4. Neckband:
   • With US 6 / 4 mm and MC, RS facing, beginning at right shoulder seam, pick up and knit:
     • 31 sts down right V-neck edge,
     • 1 st at center V (pm — this is the center st),
     • 31 sts up left V-neck edge,
     • 28 sts across back neck.
     • Total: 31 + 1 + 31 + 28 = 91 sts. ✓
   • Join to work in the round; pm at center front st.
   • Rnd 1: work k1, p1 rib to 2 sts before center st, k2tog, k1 (center), ssk, rib to end. (2 sts dec at V point)
   • Rep the centered double-decrease every rnd for 4 rnds total → 91 − 8 = 83 sts, forming a crisp mitered V.
   • BO in pattern loosely.
5. Armhole bands:
   • With US 6 / 4 mm and MC, RS facing, pick up and knit approx. 88 sts evenly around each armhole (≈ 4 sts for every 5 rows/sts).
   • Work 4 rnds k1, p1 rib; BO in pattern.
6. Attach buttons: Sew 4 buttons per side onto the back button band, aligned with the front buttonholes (8 buttons total).
7. Weave in all ends, securing color changes. Give a final light steam.

Final Measurement Check (Size M)

• Panel width: 90 sts ÷ 4.5 sts/inch = 20" → two panels = 40" bust. ✓
• Length: 15.5" body + 8.5" armhole = 24" total. ✓
• Shoulders: 22 sts ÷ 4.5 = ~4.9" each. ✓
• Back neck: 28 sts ÷ 4.5 = ~6.2". ✓
• Side split: 30 rows ÷ 6 = 5", matched by 30 picked-up placket sts. ✓

Enjoy your one-of-a-kind random stripe vest!