Blending Sizes 101: Shorts and Pants (all sizes)

We’re here today with another installment of our Blending Sizes series! Today we will be talking about how to blend between multiple sizes when sewing shorts or pants. I am going to show you how to do this for both children’s and adults’ sizes. The steps begin the same, with the difference being in how you grade for length. Let’s get started!

For the purpose of this tutorial, I will be using a very simple example of a shorts pattern. This would be the type of shorts/pants that does not have an outer seam, only an inseam. The steps are the same either way, you would just repeat the process for the front and back if the pattern had separate front and back pieces. While this tutorial shows shorts, since they are smaller and therefor easier to see in the diagrams, the steps for blending sizes are the same for pants.

Blog blending sizes

The three sizes are shown in three different colors. For this example, I will be using the green size for waist, the blue size for hip, and the middle red size for height. In children’s patterns, you will blend between these three measurements. For adults, you will follow all the instructions for waist and hip only. Do not worry about the red length size, as adult patterns are adjusted differently for height.

Marking the Blending Points

Blog blending sizes

First, draw a vertical line at the waistline on the waist size line. In this case, that is the green line. This shows where the waist width needs to finish.

Blog blending sizes

Next, find the hip size. Some patterns will include a horizontal hip line that you will use for blending sizes, but if the pattern does not have a hip line drawn in, you can draw it yourself. Simply draw a straight horizontal line across the pattern piece in the middle of the rise.

Blog blending sizes

Draw vertical lines at the hip size line, on your horizontal hip line. Then also draw vertical lines at each other width point below that line, represented in blue in the diagram.

Blog blending sizes

Then, draw horizontal lines at each height point. This is demonstrated with the red lines. If you are blending sizes for an adult size, you will skip this step.

Blog blending sizes

Finally, draw a small dot/circle at each place where your various lines intersect.

Blog blending sizes

You are ready to draw your new pattern piece! You will basically “connect the dots,” by drawing lines blending from one dot to the next, following the curves of the pattern piece (shown with black line).

Blog blending sizes

If you are blending sizes for a children’s pattern, you have finished your new pattern piece and you are ready to cut! If you are blending for an adult pattern, you at this point have followed the steps blending from waist to hip and should have your new pattern piece ready to adjust for height.

Finishing an Adult Pattern Piece:

Blog blending sizes

To adjust for height for an adult pattern, you will use the “slash and spread/overlap” method. Find the line on your pattern piece that is marked as the lengthen/shorten or height adjustment line. This will be somewhere on the leg, with the exact place having some variance for the pattern. Some shorts may not have a line as you can simply add length to the hem since it is a small amount. In this example I will assume the pattern piece has a line.

Blog blending sizes

Cut across your pattern piece on this line. Spread the two pieces apart the amount you need to lengthen. If you are shortening the pattern, overlap the pieces the needed amount.

Blog blending sizes

Redraw the lines, blending to make a smooth curve.

Blog blending sizes

That’s it! You are ready to cut out your new pattern piece!

Make sure to check out our other posts in this series to learn how to get a custom fit on bodices and sleeves!

Similar Posts