Bottom-Up DK Socks with Heel Flap & Gusset

Advanced | Adult (foot circumference 9½" / 24 cm)

A toe-up crew sock in DK weight with a wedge toe, stockinette sole, K4, P1 instep, gusset, shaped heel flap, and ribbed cuff. Worked in the round.

Sizes

One size: to fit foot circumference 9½" (24 cm) with approx 1¼" (3 cm) negative ease.
Finished foot circumference: 8¼" (21 cm).
Finished foot length: 10¾" (27.5 cm) — adjustable.

Yarn

DK weight yarn; approx 280–320 yd (255–295 m).
Sample estimate: 2 skeins at 150 yd (137 m) each.

Needles

US 3 / 3.25 mm (or size to obtain gauge): DPNs, 2 circulars, or 1 long circular for magic loop.

Notions

Stitch markers (2–4); tapestry needle; scrap yarn or stitch holder (optional).

Gauge

25 sts and 34 rnds = 4" (10 cm) in stockinette stitch in the round, blocked.
Check gauge. Sock fit depends on it.

Abbreviations (US)

BO bind off; CO cast on; dec decrease; DPN(s) double-pointed needle(s); inc increase; k knit; k2tog knit 2 together; m1L make 1 left (lift bar between sts from front to back, k through back loop); m1R make 1 right (lift bar between sts from back to front, k through front loop); p purl; p2tog purl 2 together; pm place marker; rep repeat; rnd(s) round(s); RS right side; sl slip purlwise unless noted; ssk slip slip knit (slip 1 knitwise twice, insert left needle into fronts and k2tog through back loops); st(s) stitch(es); st st stockinette stitch; W&T wrap and turn; WS wrong side; wyib with yarn in back; wyif with yarn in front.

Stitch Patterns

Stockinette (sole)
Every rnd: Knit.

Instep / Leg Pattern (multiple of 5 sts)
Every rnd: *K4, p1; rep from * to end of instep (or full rnd on leg).

1×1 Rib (optional alternate cuff)
*K1, p1; rep from *.

2×2 Rib (cuff)
*K2, p2; rep from * to end (50 sts = 12 full reps + k2).

Slipped-Stitch Heel Flap (worked flat over heel sts)
Row 1 (RS): *Sl 1 wyib, k1; rep from * to last st, k1.
Row 2 (WS): Sl 1 wyif, purl to end.
Rep Rows 1–2 for pattern.

Notes

• Socks are worked toe-up (bottom-up): toe → foot → gusset → heel → leg → cuff.
• Maintain K4, P1 on the 25 instep sts only through the foot; sole is stockinette. After heel, work K4, P1 over all 50 leg sts.
• Length is controlled by measuring from the tip of the toe. Try on if possible before gusset and before cuff.
• Magic-loop and DPN needle arrangements are both fine; keep instep and sole sts clearly divided (markers recommended).
• Inline counts use ✓ where totals are confirmed.

Pattern Instructions

Toe (Wedge)

Using Judy’s Magic Cast-On (or preferred toe-up CO), CO 10 sts (5 sts on each needle).
Join carefully; pm for beginning of rnd (between sole and instep sides as preferred). Knit 1 rnd.

Increase rnd:
Needle/Instep: K1, m1L, k to last st, m1R, k1.
Needle/Sole: K1, m1L, k to last st, m1R, k1.
(4 sts increased)

Next rnd: Knit.

Rep Increase rnd every other rnd 9 more times (10 increase rnds total) — 10 + (4 × 10) = 50 sts ✓
(25 instep sts, 25 sole sts).

Work 1–2 plain knit rnds if needed so toe measures approx 2–2¼" (5–5.5 cm) from CO.
Toe complete: 50 sts.

Foot

Establish patterns:

• Instep (25 sts): *K4, p1; rep from * to end of instep (5 reps) ✓
• Sole (25 sts): Knit.

Continue even in established patterns until piece measures 7½" (19 cm) from tip of toe,
or 3¼" (8.5 cm) less than desired total foot length (here 10¾" / 27.5 cm).
End ready to work the sole sts.

Gusset

Inc rnd: Work 25 instep sts in K4, P1 as established; on sole: k1, m1L, k to last sole st, m1R, k1.
(2 sole sts increased; total sts = previous + 2)

Next rnd: Work instep in pattern; knit sole.

Rep these 2 rnds 11 more times (12 increase rnds total).
Sole sts: 25 + 24 = 49 ✓
Total sts: 25 + 49 = 74 ✓
Gusset section ≈ 24 rnds ≈ 2¾" (7 cm).

Heel Turn

Work back and forth on the 49 sole/gusset sts only. Leave 25 instep sts on hold (or rest on cable/DPNs).

Row 1 (RS): K33, ssk, k1, turn.
Row 2 (WS): Sl 1 wyif, p18, p2tog, p1, turn.
Row 3: Sl 1 wyib, k to 1 st before gap, ssk, k1, turn.
Row 4: Sl 1 wyif, p to 1 st before gap, p2tog, p1, turn.

Rep Rows 3–4 until all sole/gusset sts have been worked and no gaps remain, ending after a WS row.
27 heel sts remain ✓ (49 − 22 decs from the paired turn rows after setup structure = 27).

Heel Flap

Work flat on the 27 heel sts, consuming any residual edge tension and firming the back of the heel. Instep remains on hold.

Work Slipped-Stitch Heel Flap pattern for 12 rows (6 slipped-st RS rows), ending after a WS row.
(Optional: on final RS flap row, k2tog once at each end to shape — see joining rnd below if you still have 27 sts.)

Joining rnd (RS, resume working in the rnd):
Knit across 27 heel sts, decreasing 2 sts evenly (e.g., k2tog near each edge of heel: 27 − 2 = 25 heel sts) ✓;
work 25 instep sts in K4, P1 as established.
Total: 50 sts ✓
Place markers at each side between heel and instep if desired (25 heel / 25 instep).

Leg

Work even in K4, P1 around all 50 sts (*k4, p1; rep from * to end — 10 reps) ✓
until leg measures 5" (12.5 cm) from end of heel flap, or 2" (5 cm) less than desired total leg height.

Cuff

Change to 2×2 rib: *K2, p2; rep from * to end.
Work until cuff measures 2" (5 cm).

Bind off: Use a stretchy BO (e.g., Jeny’s Surprisingly Stretchy Bind-Off, or k2tog tbl bind-off: k1, *k1, insert left needle into 2 sts on right needle and k2tog tbl; rep from *).
Do not BO tightly.

Finishing

Weave in ends on WS.
Block lightly over sock blockers or dampen and dry flat to measurements:
foot circumference ≈ 8¼" (21 cm), foot length 10¾" (27.5 cm).
Make second sock to match.

Schematic (key measurements)

Math Validation Summary

• Gauge: 25 sts = 4" → 6.25 sts/in; 50 sts ÷ 6.25 = 8" (20.3 cm) finished circ ✓
• Instep pattern: 25 sts ÷ 5 = 5 reps of K4, P1 ✓
• Toe: 10 CO + 40 inc = 50 ✓
• Gusset: 12 × 2 sole inc = 24; sole 25 + 24 = 49; total 74 ✓
• After heel join: 25 + 25 = 50 ✓
• Leg/cuff: 50 sts, multiples work for K4,P1 and 2×2 rib ✓

Designer / Technical edit notes for knitter:
If foot length differs, adjust the even-foot section only; keep gusset start at ~3¼" (8.5 cm) before final length so heel depth remains correct. For a taller cuff, extend rib; for ankle socks, shorten leg pattern section to 2–3" (5–7.5 cm).