Pattern Index
The course

Chapter 12

Briefs

Every number below follows the size you pick.

Briefs are drafted for stretch fabric. One frame gives the front and the back; a gusset lines the crotch.

The frame is set out from the hip, the waist to hip depth and the body rise, then made smaller for the stretch of the fabric. The leg line is a long curve, scooped more at the front or the back depending on the cut.

What you need

MeasurementWhere the tape goesSize 38
WaistRound the natural waist, where the body is narrowest, usually just above the navel.72.0 cm
HipRound the fullest part of the hips and seat, feet together.97.0 cm
Waist to hipDown the side of the body from the waist to the fullest part of the hip or seat.21.0 cm
Crotch depthSeated on a firm, flat chair: from the waist at the side straight down to the seat of the chair.26.5 cm

Drafting, step by step

Each picture shows everything drawn so far; the new line of the step is in colour. The formulas show the names of the measurements first, then the numbers for size 38.

  1. 1

    Front and back

    Step 1

    Centre line

    front and back drafted on one frame

    Briefs are drafted as one quarter: the centre front and centre back lie on the same vertical line, the side on the right. Front and back are traced off separately afterwards and each is cut on the fold.

  2. 12

    Step 1–2

    Rise

    Crotch depth + rise adjust
    = 26.5 + 0.0 = 26.5 cm

    The rise is the depth from the waist to the crotch, measured sitting. It sets how high the briefs come up the body.

  3. 123

    Step 1–3

    Hip line

    Waist to hip = 21.0

    The widest part of the hip, where the side line of the frame is set out.

  4. 1234

    Step 2–4

    Crotch length

    Hip ÷ 10 + crotch length adjust
    = 97.0 ÷ 10 + -1.0 = 8.7 cm

    The crotch runs on under the body for about a tenth of the hip girth. Front and back share it: the crotch seam sits in the middle of it.

  5. 12345

    Step 4–5

    Hip width

    Hip × (100 − fabric stretch taken off) % ÷ 4 − hip reduction per quarter
    = 97.0 × (100 − 0.0) % ÷ 4 − 2.0 = 22.3 cm

    Underwear is cut smaller than the body so it holds close. Here the quarter hip is reduced again by 2.0; a more elastic fabric takes more.

  6. 1234578

    Step 1–7

    Waist width

    Waist × (100 − fabric stretch taken off) % ÷ 4
    = 72.0 × (100 − 0.0) % ÷ 4 = 18.0 cm

    A quarter of the waist. The line from here to the hip point is the side of the body; the side seam of the briefs lies on it.

  7. 12345789

    Step 1–9

    Waist lowered at the centre

    waist lowered at centre = 8.0

    Briefs sit below the natural waist. This sets how far down the waistband sits at the centre.

  8. 123457891011

    Step 7–10–11

    Side waist and side seam

    waist lowered at side + side seam length
    = 6.0 + 5.0 = 5.0 cm

    The waist drops at the side too, and the side seam is only as long as the fabric between waistband and leg. A short side seam makes a high leg cut.

  9. 12345789101112131617

    Step 12–17

    Crotch

    crotch length ÷ 4 up and down, crotch width ÷ 2 wide
    8.7 ÷ 4 up and down, 7.0 ÷ 2 wide

    The crotch seam lies in the middle of the crotch length, so the back ends a quarter above it and the front a quarter below it. The crotch width is halved because each piece is cut on the fold.

  10. 123457891011121316171819

    Step 18–19

    Front and back waist

    front / back waist tilt = 1.0

    The back waist rises and the front waist drops so the waistband stays level on the body: the seat pushes the back down, the stomach does not.

  11. 123457891011121316171819

    Step 24–25

    Side seam moved forward

    1.0 each way: 1.0 cm

    The back side seam moves out and the front moves in, so the seam sits towards the front and the back covers more of the hip.

  12. 123457891011121316171819

    Step 11–16

    Back leg line

    nearly straight, 0.7 curve: 29.4 cm

    The back leg line runs almost straight from the side to the crotch, so the back covers the seat.

  13. 123457891011121316171819

    Step 11–17

    Front leg line

    scooped 7.0 in: 33.8 cm

    The front leg is cut away in a deep curve so the leg can move freely; the deeper the scoop, the higher the leg looks.

  14. 12345789101112131617181926

    Step 13–26

    Gusset

    gusset length = 8.0

    The crotch is lined with a gusset of cotton jersey. It is traced off the front up to this line and sewn in with the crotch seam.

  15. 12345789101112131617181926

    Step 15

    Outline of the back

    The back is traced off the frame and cut on the fold. Leg openings and waist are finished with elastic.

  16. 12345789101112131617181926

    Step 16

    Outline of the front

    The front, also on the fold. The gusset lining comes from its lower end.

The finished pieces

FRONTBACK
Women's briefs, size 38. Front (1× on fold), Back (1× on fold), Gusset lining (1× on fold). Seam allowance is added afterwards.

Sewing it

  1. Cut and mark. Cut every piece with the grain arrow parallel to the selvedge. Transfer the notches and the marks with tailor's chalk or a short snip into the seam allowance.
  2. Set up for stretch. Use a ballpoint or stretch needle and a narrow zigzag or the stretch stitch, or an overlocker. Seams in knit must stretch with the fabric.
  3. Gusset. Lay the front and the back right sides together at the crotch, the gusset on one side and its lining on the other. Sew through all four layers, then roll the pieces through and sew the lining's other edge to the front the same way so all seams end up inside.
  4. Side seams. Sew the side seams with the stretch stitch or the overlocker.
  5. Leg openings. Zigzag lingerie elastic to the wrong side of each leg opening, stretching it a little at the front and more across the back. Fold it in and topstitch with a zigzag.
  6. Waist. Join the waist elastic into a ring, divide it and the waist into quarters, sew it on the same way, fold and topstitch.
Draft it to your measurementsWatch it drawn in the editorPractise in the course