What's the Deal with Stretch Percentage?

When reading a pdf pattern, the description will often mention a stretch percentage recommendation. And if you're like me, at first you may have wondered what in the world that means.  Today, we will demystify this term so the next time you see it you can feel confident and ready with knowledge.

What is stretch percentage?

Stretch percentage is the amount of “give” a fabric possesses when held in a fixed position and stretched in the opposite direction. Woven fabrics generally have very little give. On the bias they do have a little, but today we are going to focus on knit fabrics.

Types of stretch

• Mechanical stretch is the natural stretch a knit fabric has based on the way it is constructed. Knit fabrics are constructed from a single thread knitted into interlocking loops, giving the fabric its stretch. So, even if the material does not contain spandex it will still have some give.
• Two-way stretch refers to a fabric that stretches in only one direction. I know what you're thinking, one-way stretch may seem like a more apt name to describe this property, but what the term is referring to is that the fabric stretches in two directions; left and right or up and down.
• Four-way stretch refers to a fabric that stretches both vertically and horizontally.
• Horizontal stretch is the stretch that runs across your fabric from selvage to selvage. The selvage is the self-finished edge of your fabric. You can identify the selvage by looking for a lighter strip running along the length. It may even have words printed on it.
• Vertical stretch is the stretch that runs perpendicular to the selvage, from cut edge to cut edge.

Measuring Stretch Percentage

You can download and print your free stretch percentage chart here (there's also some nifty information about our fabrics on that page as well).  You can laminate yours and keep it taped to your cutting table for quick access. Most fabric has the greatest degree of stretch running horizontally, so we will begin by determining the horizontal stretch percentage. Chose a spot that is at least 12 inches away from your cut edge and a few inches away from your selvage edge. Fold the fabric in half horizontally (from selvage to selvage). Pinch the fold between your thumb and index finger and place that hand on the beginning edge of your chart. Pinch the fold further down where the chart indicates 4”. Gently stretch the fabric until you feel
its natural resistance. You want to stretch it to its maximum capacity, but not overstretch it. You can damage the fibers by pulling too hard. The distance you are able to stretch the fabric will indicate the stretch percentage clearly marked on the chart. You will determine vertical stretch in the same manner but in the opposite direction by folding the fabric parallel to the selvage.

What is recovery?

Recovery is a fabric’s ability to go back to its original size and shape after being stretched. After you measure the stretch percentage of your fabric, you can continue to hold your fingers in place but release any tension and allow the fabric to draw back to it’s original position. If your right hand is no longer at the 4” mark, then the fabric did not recover fully and it will give you some indication of that fabric’s recovery properties. Most fibers do not have natural recovery and the addition of spandex to knit fabrics provides them with the stretch and recovery that is so crucial in making long lasting garments. Good recovery is essential when making fitted clothing such as leggings and without it the garment will become stretched out and baggy with wear.  Think about it like those favorite pair of jeans you own that fit perfectly at first but then eventually become too loose in the knees and bum area until you wash and dry them again.

Understanding Fit and Stretch Percentage

With some patterns, stretch percentage matters less, and with some, it is crucial. If your fabric has more stretch than the pattern recommends, it will fit more loosely. If it has less it will fit more snug. You can often size up or down to accommodate for a discrepancy in stretch, but it is not an exact science.

Now that you understand stretch percentage and how to measure for it, you can feel more confident and ready to buy and use more fabrics.