How to lengthen/shorten pants sewing patterns the easy way

This is a basic 101 how to shorten pants sewing patterns (or lengthen).

You’ll need your pattern, printed or ready to alter if you have a printed one already. A ruler, a tape measure, some tape (scotch style tape or painter’s tape).

Measure your inseam and outseam on your body. Measure a favorite pair of pants you like now (inseam and outseam). Average the two numbers.

Measure your pattern piece inseam and outseam, subtracting the hem and waistband (if applicable). If the pants measure 40 outseam but have a 1.5″ bottom hem and a 1.5″ foldover elastic casing, you need to subtract these to get the finished length.

Compare these measurements to get your new length. You’ll need to add back in your hem and waistband measurements once you’ve decided on a new length.

Need to go longer? You’ll use the slice and slide method.

Need to go shorter? You’ll use the fold and tape method.

If you are using a copy of your pattern you can use scotch tape to fold up or bridge the gap. If you’re using your original pattern, use blue painter’s tape to temporarily make these changes but keep the pattern intact (for instance, if you’re making cropped pants this time, but the usual length fits you well.) I often lengthen shorter pants for winter fabrics, e.g. babywale cord or twill, and crop summer fabrics like linen because those are the seasons I will be wearing the pants. Sometimes I lengthen pants so I can roll them up (for style.)

It’s super easy to change the length of pants – use all the pant pattern pieces – front, back or center front, side front and back pieces to shorten them equally. If you have perfectly straight from the knee down pants, you can just ADD to the hem length of the pattern pieces. If they are not perfectly straight, you’ll have to use the lengthen shorten lines to do this. All patterns come with these lines!