How to Lengthen or Shorten a Sewing Pattern

Sewing patterns are drafted for a “standard” height — typically 5’6” (168 cm) for women’s patterns, give or take. If you’re taller or shorter than that standard, garments cut directly from the pattern will sit wrong. Sleeves end at the wrong place; trouser hems graze the floor or float above it; bodices place darts above or below your bust point.

Lengthening or shortening is the most common pattern adjustment, and one of the easier ones to do correctly. The principle is straightforward: every pattern piece has a designated “lengthen/shorten line” where you cut the pattern apart and either spread it (lengthen) or overlap it (shorten). Done right, the proportions stay correct and only the relevant section changes length.

Where to find the lengthen/shorten line

Most modern sewing patterns include explicit lengthen/shorten lines. They’re typically drawn as horizontal double lines across the pattern piece with text labelling them — sometimes “lengthen/shorten line” written along the line itself, sometimes a small note in the pattern instructions.

These lines are placed at sections where length can be added or removed without distorting the design:

Bodice front and back: between the underarm and the waist (the torso between bust and waist).
Sleeve: between the underarm and the elbow, sometimes a second line between elbow and wrist.
Skirt or trouser: between the hip and the knee, often a second line between knee and hem.

Some pattern pieces have one line; others have two or three for finer control over which segment of the garment changes.

If your pattern doesn’t have explicit lengthen/shorten lines (older or simpler patterns sometimes don’t), you can draw your own — see “drafting your own line” below.

How much to add or subtract

Common adjustments by height:

Per inch (2.5 cm) of total height difference: roughly 1.5 cm bodice + 1 cm trouser/skirt + 1 cm sleeve.

But this is a rough rule. Better: measure yourself and compare to the pattern’s measurements.

Bodice length

Take your back length measurement (from base of neck to natural waist). Compare to the bodice back’s measurement at the same points on the pattern. The difference is the adjustment needed.

Most patterns assume a back length around 41 cm (16 inches). If your back length is 38 cm, you need to shorten the bodice by 3 cm. If yours is 44 cm, you need to lengthen by 3 cm.

Sleeve length

Take your sleeve length measurement from shoulder tip to wrist. Compare to the pattern’s sleeve length. The difference is the adjustment needed.

Trouser inseam

Compare your inseam to the pattern’s inseam (printed on the pattern piece or in the size chart). Adjust by the difference, distributing roughly 60% above the knee and 40% below for natural proportions.

Skirt length

Decide where you want the hem to sit, measure from your natural waist down to that point, and compare to the pattern’s skirt length.

Step-by-step: lengthening a bodice

Suppose your back length is 44 cm and the pattern is drafted for 41 cm. You need to add 3 cm.

Tools

The pattern piece (bodice front, then bodice back — repeat the process on each).
Scissors or rotary cutter.
A clear ruler.
Tape (Scotch or paper tape).
A pencil.

Process

Trace the pattern if it’s a tissue paper pattern. Don’t cut the original. Use your traced copy for adjustments.
Locate the lengthen/shorten line on the bodice piece.
Cut along the line with scissors. The pattern piece is now in two parts.
On a piece of plain paper or pattern tracing paper, draw a horizontal line. Tape the upper bodice piece to the paper along this line.
Measure 3 cm down from the cut edge of the upper piece, draw a parallel line.
Tape the lower bodice piece so its cut edge sits on the line you just drew. The bodice is now 3 cm longer.
Re-draw the side seam smoothly across the gap. The original side seam was a straight line or gentle curve; reconnect it through the gap.
Re-draw any darts, notches, or other details that crossed the cut line, repositioning them as needed for the new length.

The pattern is now 3 cm longer through the bodice section. The shoulders, neckline, and bust are unchanged; the section between bust and waist has been extended.

Step-by-step: shortening a bodice

The mirror process. You’re removing length instead of adding.

Trace the pattern.
Locate the lengthen/shorten line.
Decide how much to remove (e.g., 3 cm).
Draw a parallel line 3 cm above the lengthen/shorten line.
Fold the pattern along the lower (original) line, bringing the fold up to meet the upper line. Tape in place.
Re-draw side seams smoothly across the fold.
Re-draw darts and notches as needed.

The pattern is now 3 cm shorter. Same shape, less length in the torso.

Lengthening or shortening sleeves

The principle is the same. Cut along the lengthen/shorten line, spread or overlap by the desired amount, re-draw the seams smoothly.

A few notes specific to sleeves:

Two lengthen/shorten lines on long sleeves: one between underarm and elbow, one between elbow and wrist. Adjust each according to where you need length: if your forearm is short but your upper arm is normal, only adjust the lower line.
Sleeve cap is sacred: don’t lengthen or shorten through the sleeve cap. The curve of the cap is matched to the armhole; changing it distorts the fit. Only adjust below the cap.
Cuff and finishing details unchanged: the cuff or sleeve hem doesn’t move; the length is added or removed in the middle of the sleeve.

Lengthening or shortening trousers and skirts

Same principle. The trouser pattern’s lengthen/shorten line is typically between the hip curve and the knee, and sometimes a second line below the knee.

For trousers especially, distribute length adjustments naturally:

Tall person, long legs overall: adjust both upper and lower leg sections proportionally.
Tall person, long thighs only: adjust only the upper line.
Tall person, long calves only: adjust only the lower line.

Check yourself in fitted trousers: where does the knee of the trouser sit relative to your knee? If too high or too low, the upper-section length is wrong.

Drafting your own lengthen/shorten line

If your pattern doesn’t include one:

For a bodice: draw a horizontal line about halfway between the underarm and waist points, perpendicular to the centre front (or centre back).
For a sleeve: draw a horizontal line about halfway between the underarm and the elbow.
For trousers: draw a horizontal line about 5–8 cm above the knee.
For a skirt: draw a horizontal line about halfway between the hip and the hem (or midway through the skirt’s length).

Avoid drawing the line through critical features — darts, pocket placements, button positions, design details. The line should pass through “neutral” sections of the pattern.

Common mistakes

Adjusting at the hem instead of the lengthen/shorten line

Tempting — just add 5 cm at the bottom of the trouser, right? But this distorts the proportions. The original pattern was drafted with the knee at a specific position; lengthening only at the hem moves the knee position relative to the hip (now too high in the leg).

Always adjust at the lengthen/shorten line, then re-cut the hem if needed.

Exception: minor hem adjustments (1–2 cm) for personal length preference are fine to do at the hem only. Larger adjustments need to use the proper line.

Forgetting to re-draw side seams smoothly

After cutting and spreading, the side seam has a gap or step where it crosses the cut. If you sew along the original (now disconnected) line, the seam will jog awkwardly. Always re-draw side seams as smooth lines across the adjustment.

Lengthening one piece and not the matching piece

If you lengthen the bodice front, you must lengthen the bodice back by the same amount, in the same place. Otherwise the side seams won’t match in length and the garment is unsewable.

Same for sleeves (only one sleeve piece typically, but double-check) and trouser front/back.

Adjusting before checking the pattern’s own measurements

Some patterns include extra ease or unusual proportions. Before adjusting blindly, measure the pattern at the same points you measured your body. If the pattern says “back length: 41 cm” and you measure the actual paper from the neck point to the waist and get 41.5 cm, the pattern is drafted accurately. If you measure 38 cm, it’s drafted shorter than stated, and you should adjust by less than the body-measurement difference.

Combining length adjustments with other fit changes

Length adjustments are often done alongside other fit modifications:

FBA (full bust adjustment): usually done first, before length adjustments. The FBA may change where the bust apex sits, which can affect waist length. See our FBA guide.
Sway back adjustment: shortens the centre back without affecting side seams. Done after general length adjustment.
Forward shoulder adjustment: shifts the shoulder seam without changing length. Independent of length adjustment.

Make a muslin after each major adjustment to verify the fit. See our muslin guide for the process.

Closing thought

Lengthen/shorten adjustments are the gateway to pattern alteration — the simplest, most-needed, and most-rewarding modification you’ll learn. Once you’ve adjusted one pattern to fit your height properly, every garment from then on can be tailored to your actual body rather than the pattern’s standard.

A taller-than-average sewer who skips this step ends up with trousers that hover above the ankle and bodices that sit too high on the torso. A shorter sewer ends up with sleeves dangling past the wrist and dresses that drag. Five minutes of pattern adjustment fixes both.

For the broader pattern-handling context, our understanding sewing patterns guide is the umbrella reference.