Pattern alterations

Why and how

Why pattern alterations are made

Patterns are altered primarily for two reasons: either to improve the fit of the garment or to alter its appearance. With both, the objective is to make the clothing fit the wearer as well as possible, and to ensure they enjoy wearing it.

The aim of fit alterations is to make a piece of clothing into something that is adapted to and suits the wearer’s individual body. Both ready-made clothes and sewing patterns are usually designed for a ‘neutral’ body type, since it is impossible to create a pattern for clothes that will fit everyone with no need for alteration. This is why we often have to refine patterns slightly.

A well-fitting garment looks good and flattering, as its proportions are right and the individual details are at the right points, with no straining wrinkles or excess ease. A well-fitting garment also feels pleasant to wear, does not restrict movement or have to be adjusted from time to time in order for the garment to look and feel good.

Fitting dolls

Determining the necessity and amount of alterations

The necessity and extent of any pattern alteration depends on the difference between your own measurements and those of the size chart, as well as on the type of the garment. The need for alterations and the number of alterations relate directly to how loose the garment is – the more tailored the fit, the more adjustments may need to be made to the pattern and the bigger the adjustments may need to be. The fit of looser or stretchy garments will not necessarily need to be altered in any other way than the length, and the amount of the alteration for a loose garment may also be smaller than for a tailored piece.

Compare your own measurements to those in the size chart in order to determine how much to remove from or add to the pattern. Never use the finished measurements of the garment as a starting point for pattern alterations, unless you specifically want to alter the ease in the pattern! Instead, always preserve the pattern’s original ease (ease means the difference between the size chart and the finished measurement, and it can also be negative in garments that are made of stretch fabrics). See the detailed measuring instructions and size chart here.

You can also assess and measure where and how much the pattern needs to be altered by studying your toile. If the toile is strained, you can cut it open across the strains and allow the cut to open enough for the strain to loosen. Pin a piece of fabric under the cut, and measure the amount the piece has been opened by. Transfer this addition to your pattern. If the toile is saggy or too loose, the fabric can be sectioned and pinned off into a dart or a pleat, so that the sagginess or excess ease is removed. Afterwards, open the pleat, measure it, and remove the same amount from the pattern.

Measuring tape

The 'slash & spread' method

We have used the so-called ‘slash and spread/overlap’ method, where alteration lines are drawn onto the pattern, cut open, with the pieces then slid on top or apart from each other. The alteration lines are drawn with a pink line in our diagrams. Sometimes the lines are cut open so that a small section is left at the end of the line, just a millimetre or so long, as a ‘hinge’, or ‘pivot point’. This pivot point stays in place when the other parts of the pattern move. A small pink dot marks the pivot point in the illustrations.

The slash and spread/overlap pattern altering method

When moving the pieces, keep a large piece of pattern paper underneath them, to which you can tape pieces that are not moving, and only move those parts that need to be moved. Draw guide lines onto the pattern or the paper underneath it, to help you move the pieces and tape them at the right distances from each other. Once you’ve made the alterations, tape all the pieces carefully in place.

Moving the pattern pieces when altering the pattern

Remove the seam allowances from all the edges the pattern alteration will affect, and add them back in after the alterations. As pattern lines are not always straight, seam allowances do not generally correspond to the shape of the piece, and instead may distort it and complicate the alteration. All our patterns include a 1 cm (3/8”) seam allowance, unless otherwise indicated. Draw the seam allowances on the pattern 1 cm (3/8”) (or otherwise if stated in the pattern) inside the cut line. You can cut off a small section from the seam allowance at parts where the pattern is altered, usually where the slash or pivot point is at the edge of the pattern. Remember to also copy any notches onto the line and transfer them back to the new seam allowance afterwards.

Removing the seam allowances before altering the pattern

Before you start

Go from the largest alterations to the smallest: First, alter the lengths of the pattern, then, if necessary, the width of the bust, waist, and hips. Sew together a toile/muslin to see whether any refinements to the pattern are still needed.

Bear in mind that if your garment is symmetrical, usually you will work on altering a half or, one fourth of its width. For example, the front pattern piece just represents half of the front, and its width will be doubled when cut out on double thickness. If, for example, you want to add 2 cm (3/4”) of ease at the bust, increase the front pattern piece by 1 cm (3/8”). Whilst if you add 2 cm (3/4”) to the waist circumference, you can add 0.5 cm (1/4”) to the front piece and another 0.5 cm (1/4”) to the back piece, because the alteration is now repeated four times.

Adding or reducing ease equally when altering the pattern

Remember to always carry out changes to all pieces the pattern alteration affects, for example any pocket facings, pocket bags, waist bands or similar. If your garment features a lining, make sure to alter not just the shell but also the lining parts, so that all the pieces fit together. Also check whether the alteration affects the size or positioning of individual details and alter the size, shape and location of individual details as necessary, so that they look good, and so that, for example, the slits and zips are long enough to allow the garment to be put on and taken off. Also take into consideration that sometimes the measurements of the zip should be left unchanged so that you can use a standard-length zip without having to shorten it.

Lengthening and shortening

In order to determine how much you might need to alter the pattern lengths, compare your own length measurements to those of the size you have chosen. Lengthen or shorten the pattern only at the points where the length measurements differ, to correspond to the differences between the two sets of measurements at those points. Check out our size chart and learn to take your own measurements here.

Lengthening and shortening line

Start by drawing a lengthening or shortening line: Draw the line between the two body lines, perpendicular to the grain line. On the back piece of trousers, draw the line parallel to the hip line. Always draw the lines at the same height on the front and back pieces:

  • Back length: Draw the line between the bust and waist (A). If the difference from the size chart measurement is more than 3 cm (1 1/4”), you can, if you wish, draw another line above the bust, above the armhole notches (B), and divide the alteration evenly between the lines. If you are doing this, remember to draw the line to the sleeve cap, if present in the pattern, at the same height.
Altering the back length of the pattern
  • Waist-to-hip: Draw a line between the waist and hip lines (A). On the back piece of trousers, draw the line parallel to the hip line (B).
Altering the waist-to-hip length of the pattern
  • Arm length: Draw two lines, one between the bicep and elbow lines, and the other between the elbow line and sleeve end. Distribute any difference in the arm length measurement evenly along these lines (A). If the sleeve is short, straight, or narrows or broadens evenly, you can draw just one line instead of two (B).
Altering the arm length of the pattern
  • Inseam: Draw two lines, one between the thigh and knee lines and one between the knee and leg end (A). Distribute any difference in the inner leg measurement evenly along these lines. If the leg is short, straight, or narrows or broadens evenly, you can draw just one line instead of two (B).
Altering the inseam length of the pattern
  • Side length: Draw two lines, one below the hip line and the other between the first line and hem line (A). Distribute any difference in the side length evenly along these lines. If the skirt is short, straight, or narrows or broadens evenly, you can draw just one line instead of two (B).
Altering the side length of the pattern

Lengthening and shortening

Shorten or lengthen the pattern along the line you have drawn. Always move the patterns vertically up or down. To help, you can draw a guide line onto the pattern, perpendicular to the shortening or lengthening line, before cutting the pieces, ensuring that you make the alteration in the direction of the line.

  • Cut the pattern into two pieces along the length alteration line. (A)
  • When lengthening, tape the lower pattern piece to the backing paper. Draw a guideline onto the top of the piece, the required distance from the lower piece, and tape the higher piece to this line. (B)
  • When shortening, tape the pieces correspondingly so that they are overlapping the necessary amount. (C)
Lengthening and shortening the pattern
  • True the pattern edges by drawing them smooth and measuring that all matching edges are of equal length.
Truing the pattern edges

Truing the altered patterns

Altered patterns should always be finalised before adding in the seam allowances, in order to be sure that the pieces are smooth in shape and can still be sewn together.

Truing pattern edges

Draw the outer lines of the altered pattern neatly and smoothly, for example if openings or corners have been formed along these lines during the process.

Truing the outer lines of the altered pattern

Truing darts

If you altered the pattern at the dart, redraw the sides of the darts afresh, without any breaks in the dart (A). Neaten up the end of the dart and even out the sides: Tape a piece of paper under the pattern at the end of the dart (B). Fold the dart together along the centre line so that the sides meet, yhen fold the dart in the direction it will be ironed in in the finished piece (C). Hold the pattern tightly in place and draw the seam neatly and smooth at the end of the dart. (D) Cut along the line with a circular cutter, or draw along the line with a roller in order to copy it onto all layers and then open the dart and cut the edge neatly along the line with scissors. (E)

Truing the darts of the altered pattern

Truing seams

Measure to make sure that the altered seams match up with their opposite pieces and that the notches correspond. Measure the seams just in the altered area, for example from one edge to the other or to the nearest notch. Note that sometimes pieces, such as sleeve caps, feature easing, i.e. the piece is longer than the piece it's supposed to be sewn onto. Take this easing into account when measuring the pieces and ensure you retain the amount of ease stated.   In our Post-2020 patterns any such easing and the amount used are always stated in the pattern.

Truing the seams of the altered pattern

If a piece has shortened or lengthened, first make sure that there are no errors in the pattern that would create differences. If there is a difference of 4 mm, for example, even out the seam by removing 2 mm from one piece and adding 2 mm to the other.

Evening out the seams of the altered pattern

Truing angles

Check that any angles in the pattern are right angles, or otherwise line up with the pieces to be joined to them. If this is not the case, neaten up the angle.

Right angles: Draw the angle onto the piece again at 90 degrees with a ruler, and merge the line neatly with the original line. Place any pieces to be sewn together against each other and check that the line is smooth.

Truing the angles of the altered pattern

Other angles: Place the pieces to be sewn together against each other and draw a line neatly and smoothly, using a curve ruler, for example.

Truing the angles of the altered pattern

Truing markings

The markings indicating the locations of individual pattern details, such as pockets, may be moved when making alterations. Copy the new locations for the markings at your discretion, as far as is possible, placing them in the same positions as in the original pattern.

Truing the markings of the altered pattern

Adding seam allowances

When you have altered and trued your pattern pieces, add the seam allowances to them and move the notches to the edge of the seam allowance. It may be a smart idea to trace the entire finished pattern afresh onto pattern paper, and add the seam allowances then, so that your altered pattern is neat and easy to store for future use.

Adding the seam allowances to the altered pattern

 

FULL BUST ADJUSTMENT (FBA)

It’s easy to estimate whether you need to make a full bust alteration or not, by comparing your own full and high bust measurements to those of our size chart. If your full bust circumference is larger than the size chart's, making a full bust adjustment is probably a good idea.

  • Draw the seam allowances where necessary, and remove them if you wish.
  • Draw a line along the center of the bust dart to the bust apex (A). Draw another line from above the sleeve notch, to the bust apex (B). Draw a third, vertical line from the bust apex to the hem (C). Draw yet another line from the line C to the center front (D).

Full bust adjustment

  • Cut the lines open, leaving pivot points on the armhole and apex.
  • Slide the side pieces apart, to open the front the desired amount. This will cause the bust dart to spread. Make sure the line C remains vertical. Slide the center piece down to level it with the hem, making sure the center front is in line. Tape in place.

Full bust adjustment

  • True the armhole, side and hem edges. True the bust dart by drawing its sides until they intersect. True the end of the bust dart. 
  • Add or smooth the seam allowances.

Full bust adjustment

 

SMALL BUST ADJUSTMENT (SBA)

You can estimate whether you need to make a small bust alteration by comparing your own full and high bust measurements to those of our size chart. If your full bust circumference is smaller than the size chart’s, you can alter your pattern with a small bust adjustment.

  • Draw the seam allowances where necessary, and remove them if you wish.
  • Draw a line along the center of the bust dart to the bust apex (A). Draw another line from above the sleeve notch, to the bust apex (B). Draw a third, vertical line from the bust apex to the hem (C). Draw yet another line horizontally from the line C to the center front (D).

small bust adjustment

  • Cut the lines open, leaving pivot points on the armhole and apex.
  • Slide the side pieces to overlap with the center pieces by the desired amount. This will cause the bust dart to narrow. Make sure the line C remains vertical. Slide the center piece up to level it with the hem, making sure the center front is in line.

small bust adjustment

  • True the armhole, side and hem edges. True the bust dart by drawing its sides until they intersect. True the end of the bust dart.
  • Add or smooth the seam allowances.

small bust adjustment

BROAD BACK ALTERATION

You know you need a broad back alteration if your toile or garment feels too tight at the upper back, making it hard to lift your arms and reach them to the front. If you have made a toile, you can cut it open vertically next to the back armscyes, to figure out how much excess ease you will need to add.

  • Draw the seam allowances where necessary, and remove them if you wish.
  • Draw a short, slanted line from the corner where the shoulder seam and armhole meet. Then continue the line down to the side seam at waist (A). The line should be long and slanted enough to not touch the armhole. Draw a horizontal line from the corner where the armhole and side seam meet, to the line A (B). Draw a third line from just above the armhole notches to the line A (C).

Broad back alteration

  • Cut the lines open, leaving pivot points to their outer ends.
  • Slide the side pieces outward, to let the pattern open the desired amount. Tape in place.

Broad back alteration

  • True the shoulder, armhole and side edges.
  • Add or smooth the seam allowances.

Broad back alteration

NARROW BACK ALTERATION

If your garment or toile feels loose and baggy at your upper back, it might need a narrow back alteration. You can pin the toile or garment vertically next to the back armscyes to figure out how much ease to remove from the pattern. Remember to take only as much as needed, so that you can still lift and reach your arms to the front without the garment restricting your movement.

  • Draw the seam allowances where necessary, and remove them if you wish.
  • Draw a short, slanted line from the corner where the shoulder seam and armhole meet. Then continue the line down to the side seam at waist (A). The line should be long and slanted enough to not touch the armhole. Draw a horizontal line from the corner where the armhole and side seam meet, to the line A (B). Draw a third line from just above the armhole notches to the line A (C).

Narrow back alteration

  • Cut the lines open, leaving pivot points to their outer ends.
  • Slide the side pieces inward, to overlap them by the desired amount. Tape in place.

Narrow back alteration

  • True the shoulder, armhole and side edges.
  • Add or smooth the seam allowances.

Narrow back alteration

NARROWING THE NECKLINE

If your shirt pattern feels too loose around the neck, it’s a good idea to alter the neckline slightly narrower. You can pin your garment or toile at the center back to determine how much narrower you would like the collar to be. Remember to divide the amount by four, and remove it from the front and back piece, as well as the collar and collar stand pieces.

  • Draw the seam allowances where necessary, and remove them if you wish.
  • Draw a line down from the shoulder seam, and continue it in a 90° angle to the front/back (A). Make sure to draw the line on the same spot on the shoulder in both the front and back. Draw another line from the center of the neckline to the line A (B). 

Narrow neckline alteration

  • Cut along the alteration lines, and tape the biggest piece on a large piece of pattern paper. Draw guidelines on the backing paper along the shoulder seam and front/back.
  • Slide the smaller pieces along the guidelines so that they overlap the desired amount at the line B. Tape in place.

Narrow neckline alteration

  • True the neckline curve.
  • Add or smooth the seam allowances.

Narrow neckline alteration

  • Alter the collar and collar stand: Draw alteration lines C & D on the same spots on the collar pieces, as where the line B was on the bodice pieces.
  • Cut the lines open. Slide and overlap at these lines by the same amount as in the bodice patterns. True the edges and add or smooth the seam allowances.

Narrow neck alteration

WIDENING THE NECKLINE

If your shirt feels uncomfortably tight around the neck, you can alter the collar and the neckline wider. To determine how much to add, you can open the collar button, and pin the collar closed where it feels comfortable. Measure the distance of the button and the buttonhole to see how much to add. Remember to divide the amount by four and add it on the front and back piece, as well as the collar and collar stand pieces.

  • Draw the seam allowances where necessary, and remove them if you wish.
  • Draw a line down from the shoulder seam, and continue it in a 90° angle to the front/back (A). Make sure to draw the line on the same spot on the shoulder in both the front and back Draw another line from the center of the neckline to the line A (B). 

Wide neck alteration

  • Cut along the alteration lines.
  • Slide the smaller pieces along the shoulder seam and front/back, so that they open the desired amount at the line B. Tape in place.

Wide neck alteration

  • True the neckline curve.
  • Add or smooth the seam allowances.

Wide neck alteration

  • Alter the collar and collar stand: Draw alteration lines C & D on the same spots on the collar pieces as where the line B was on the bodice pieces.
  • Cut the lines open. Slide and open at these lines by the same amount as in the bodice patterns. True the edges and add or smooth the seam allowances.

Wide neck alteration

Kielo: full bust adjustment with an added bust dart

You can make a full bust adjustment (FBA) to the Kielo dress or jumpsuit pattern in two ways: with or without a bust dart. Adding a dart is recommended, if your fabric is very stiff (such as heavy ponte) or if you have to alter the bust size by a great deal, one size or more. If your fabric is light, drapey or very stretchy, we recommend the full bust adjustment without a dart.

  • Draw the seam allowances where necessary, and remove them if you wish.
  • Draw a line from the center of the shoulder seam to the bust apex (A). Continue the line vertically to the hem (B). Draw another line from above the armhole notch to the bust apex (C), and then yet another, horizontal line from the midpoint of the shoulder seam and the notch at the armhole, to the line A (D).

Kielo bust dart

  • Cut the lines open leaving pivot points to the spots indicated.
  • Slide the side pieces apart to open the pattern at the apex by the desired amount, and to spread the bust dart. Tape in place.

Kielo bust dart

  • True the dart end, the shoulder and the armhole, as well as the hem. Shorten the bust dart so that its tip is 2 – 5 cm (3/4 – 2”) from the apex. The right distance depends on the size and shape of your pattern and bust, as well as of the depth of the dart: the larger the size, the further apart from the apex the dart should be. The deeper the dart is, the longer it should be, to avoid it from becoming very steep.
  • Add or smooth the seam allowances.

Kielo bust dart

KIELO: FULL BUST ADJUSTMENT

There are two ways to make a full bust adjustment (FBA) to the Kielo dress or jumpsuit: with or without a bust dart. If your fabric is light, drapey or very stretchy, we recommend this full bust adjustment without a dart. Adding a dart is recommended, if your fabric is very stiff (such as heavy ponte), or if you have to alter the bust size by a great deal, one size or more.

  • Draw the seam allowances where necessary, and remove them if you wish.
  • Draw a line from the center of the shoulder seam to the bust apex (A). Continue the line vertically to the hem (B). Draw another line from the armhole notch to the bust apex (C), and then another from above the sleeve notch to the apex (D). Draw one more, horizontal line from the midpoint of the shoulder seam and sleeve notch, to the line A (E).

Kielo full bust adjustment

  • Cut the lines open, leaving pivot points on the armhole and shoulder.
  • Slide the side pieces apart to open the front the desired amount. Tape in place.

Kielo full bust adjustment

  • True the shoulder, armhole and hem edges.
  • Add or smooth the seam allowances.

Kielo full bust adjustment

KIELO: ADDING A BACK CONTOUR DART

If you want to add shape and contour to the back your Kielo dress or jumpsuit, you can do that by adding contour waist darts. It’s easy to decide how much to remove and where to place the darts using a toile, but you can also add the darts before making the first toile. If you have a toile, pin the excess ease off from the back at the desired spot, into two contour darts, and measure the depth of one dart, as well as its distance from the center back seam. Note that one dart shouldn't be deeper than 3 cm (1 1/4”).

  • On the back piece, mark the placement for the dart on the waist, at the desired distance from the center back (A). You can use a distance of 5.5–8 cm (2 1/4–3 1/4”), depending on the size: the larger the size, the further the dart should be from the center back. Remember to take into account the seam allowance and start measuring 1 cm (3/8”) in from the pattern edge.
  • Mark the depth of the dart on the waist line (B) The depth should be 1.5–3 cm (5/8–1 1/4”), depending on how much ease you want to remove. 

Kielo waist contour darts

  • Measure the midpoint of the dart, and draw a vertical line through it, from the bust line to hip line. (C)
  • Draw the end points of your contour dart on the center line. The dart should be about 14–16 cm (5 1/2–6 1/4”) long upwards (D) and 14–16 cm (5 1/2–6 1/4”) downwards (E). The length depends on your own height and shape, and also of the depth of the dart: the deeper the dart, the longer it should be to avoid too steep darts).

Kielo waist contour darts

  • Draw the sides for the contour dart using a ruler (F).
  • Finish the dart by making sure you mark its tips on the pattern and on your fabric. Sew a toile before cutting your actual fabric.

Kielo waist contour darts