A punch hole from fabric-weight testing is the circular opening left when a small sample is cut from a fabric roll and weighed to calculate GSM (grams per square meter). It does not automatically mean the rest of the roll is unusable.
Still, finding a circle missing from a new roll can be a surprise. Here’s the explanation behind the cutout in Blue Moon Fabrics’ original Instagram Reel, along with what to check before ordering or cutting.
Why are circular samples cut from fabric?
A sample cutter removes a piece with a known area. Weighing that piece allows the fabric’s weight per unit area to be calculated and compared with its specifications. The circle is left behind because the test uses the fabric sample itself.
What does GSM mean in fabric?
GSM stands for grams per square meter. It describes how much a square meter of fabric weighs.
A common circular sample cutter removes 100 square centimeters of material. That’s one hundredth of a square meter, so the sample’s weight in grams is multiplied by 100 to calculate GSM.
For example, if a 100-square-centimeter sample weighs 2 grams, the result is 200 GSM. That’s an illustration of the calculation, rather than a specification for the fabric in our Reel.
GSM tells you about fabric weight. It doesn’t, by itself, tell you how stretchy, opaque, supportive, or suitable a fabric will be for your project.
Why take the sample away from the edge?
The sample needs to represent the fabric you’ll actually use. Small-swatch weight testing excludes the selvage—the lengthwise edge of the fabric—unless a selvage allowance is specified.
With stretch fabrics, how the material is held also matters. Pulling a piece taut changes the area it covers, so a stretched sample and a relaxed sample aren’t directly comparable.
You may find a cutout in the body of the fabric, as we showed in the Reel. That doesn’t mean every weight-test sample must come from the exact center; sampling locations depend on the testing procedure.
Why might a hole appear partway through a roll?
As we explained in the Reel, a sample may be taken during a production run, rather than only at its beginning or end. That can leave a test cutout somewhere you won’t see until you unroll more fabric.
The location may be inconvenient for your layout. The next step is to check where it falls before cutting.
How to cut around a punch hole
- Inspect your fabric first. Locate the cutout before committing to your pattern placement.
- Keep the opening outside your cut pieces. Check the full outline of each piece, including seam and hem allowances.
- Preserve your pattern’s layout requirements. Keep the grainline and required stretch direction correct. For directional prints or nap, keep those aligned too.
- Check every layer. If you’re cutting folded fabric, make sure the opening doesn’t fall inside a pattern piece on the layer underneath.
Don’t stretch the fabric to squeeze a pattern piece around the hole. Reposition the pieces on relaxed fabric instead.
Does Blue Moon Fabrics add extra yardage for punch holes?
At Blue Moon Fabrics, we add extra yardage to account for fabric-weight test cutouts. Check your fabric and pattern layout before cutting, since extra length does not remove the interruption where the sample was taken.
Need a continuous, uninterrupted piece of fabric?
Please contact us before placing your order if your project requires one continuous, uninterrupted piece of fabric. Tell us which fabric you need and the uninterrupted length your project requires, so our team can check what is available before you buy.
This is especially useful for large panels or layouts that cannot be repositioned around a test cutout. Contact Blue Moon Fabrics about continuous yardage or email info@bluemoonfabrics.com.
Found a punch hole but no extra yardage?
If you find a fabric-weight test hole and, after measuring your fabric, realize no extra yardage was included, please contact us. We can arrange a refund or send additional yardage free of charge.
Include your order number, the fabric name, a photo of the cutout, and the length you measured so we can help resolve it.
If you are unsure what caused a hole, or it prevents your planned cutting layout, contact our team for help.
Frequently asked questions about punch holes in fabric
Is every hole in fabric a weight-test hole?
No. This guide explains the deliberate circular test cutout shown in our Reel. Tears, snags, irregular openings, and other damage should be checked separately.
Can I sew directly over the hole?
For an intact garment panel, keep the opening outside the entire cut piece. Sewing across it won’t restore the missing fabric.
Does the cutout mean the whole roll failed testing?
No. The opening shows that a sample was removed; it doesn’t tell you the test result.
Want to see the cutout we’re talking about? Watch our original explanation on Instagram.
More fabric guidance
For more help working with stretch fabrics, read our tips for using spandex fabric effectively.
Technical references
- James Heal: Sample Cutters — circular, known-area specimens for measuring fabric weight.
- ASTM D3776/D3776M: Mass Per Unit Area (Weight) of Fabric — fabric-weight test methods, including small-swatch sampling.
This guide explains the sample cutout demonstrated by Blue Moon Fabrics. It does not certify the test result of an individual roll.
