This adjustment is used to maintain the proportions of a garment on different heights. Ideally, you should apply it when your height differs by at least 2.5 cm (1”) from the standard used by the designer. Before you start, be sure to have this information in hand to compare both measures.
To make the process easier, most of the sewing patterns include adjustment lines. Refer to the pattern symbols list to identify them, then slash the pattern pieces where indicated.
Once this is done, spread the pieces to lengthen the pattern (figure 1.1) or overlap the pieces to shorten (figure 1.2). When you are lengthening a pattern, place some pieces of paper underneath to fill in the gaps.
Either way, use the grainline on the pattern to guide you when moving around the pieces, then be sure that it remains aligned on each side of the adjustment lines. If you need to, extend the grainline all the way to the pattern edges.
Distribute the measure to add or remove to all the adjustment lines of the pattern. However, the measure is not always evenly distributed and will vary according to where the line is located. Start at the legs, because this is where you’ll need to distribute most of the measure. Then, the higher you go along the body, the least you’ll give out.
For instance, you may distribute 5 cm (2”) along the legs, then 2.5 cm (1”) to the torso and along the arms, but only 0.5 cm (¼”) to the armholes and sleeve head.
Once you are done with the adjustment, be sure to rebalance the placement of any pockets, as well as the buttons/buttonholes symbols so that they are evenly placed.
The height adjustment may also alter the seams where a zipper will be sewn to. In this case, be sure to use a length that will be suitable for the new pattern.