How to check fabric stretch percentage

Let’s talk about fabric stretch because I promise you, it’s not as complicated as it sounds!

If you’ve ever looked at a knit sewing pattern that says something like 'fabric with 40% stretch required' and thought yes but how do I actually know that?? then you are not alone. In fact, this was me for years when I was scared to sew with knit fabrics (LOL)

Once you know this little trick, you’ll be checking stretch in seconds, whether you're in a fabric shop or digging through your stash at home.

What is stretch percentage?

Stretch percentage is just a way of measuring how much your fabric can stretch compared to its original length.

So when a sewing pattern asks for:

20% stretch → a little bit of give
40–50% stretch → nice and stretchy (perfect for fitted garments)
70%+ stretch → super stretchy (like activewear and swimwear)

The more stretch, the more the fabric will hug your body ✨

What you’ll need

Your fabric
A ruler (or even just a tape measure)
2 pins (or you can just hold it)

How to check stretch percentage

1. Pin a 10cm section

Line up your fabric against a ruler and measure 10cm across your fabric, going across the width (crosswise grain) - this is usually where the stretch is.

I like to add 2 pins 10cm as this is a good visual to check stretch recovery too. If you're out and about in fabric shops and don't have access to pins, then holding the fabric 10cm apart will work also.

Image showing 2 pins in fabric to check for stretch percentage

2. Gently stretch the fabric

Now stretch the fabric gently (not pulling it to death - we’re not testing its limits here 😅). Keep the left pin at the 10cm mark and stretch the right pin until you feel a good resistance without distorting the fabric.

You just want to stretch it to where it naturally feels comfortable.

Just because you CAN stretch it further doesn't mean that's correct. Example below showing it stretching much further, but this would be very uncomfortable to wear and may end up feeling like a second skin (or you may not be able to get it on at all!)

3. Measure the stretched length

Let’s say your 10cm piece stretches to:

12cm → that’s 20% stretch
14cm → that’s 40% stretch
15cm → that’s 50% stretch

In the example above, there’s been an increase in 4cm which equates to 40% stretch.

Don’t forget about recovery

Stretch is only half the story. You also want to check recovery which is where we look at the fabrics ability to bounce back.

Let's have a look at this pointelle...

You can see below it comfortably stretches to almost 26cm

But it doesn’t have good recovery as you can see it has grown 1cm after being stretched.

So this fabric wouldn't be a great choice for fitted garments.

Using fabrics with different stretch percentages

If your fabric is slightly under the recommended stretch, it could still work depending on the fit of the garment or you may wish to size up. If your fabric is slightly over the recommended stretch, you may wish to size down depending on the fit of the sewing pattern.

Ensure the fabric has good recovery to prevent the garment from growing during wear.

Final thoughts

Checking stretch percentage might feel like one of those technical sewing things but it’s actually such a quick and empowering skill to learn.

It helps you choose the right fabric with confidence which avoids disappointing makes! 💫