Why Does My Acrylic Vary in Size or Thickness?

If you've been working with acrylic for a bit, you may have noticed something: not all sheets are exactly the same size or thickness. Don’t worry, your eyes aren’t playing tricks on you, and it’s not a mistake. There’s actually a good reason for this, especially when it comes to cast acrylic.

Let’s Talk About Thickness

Most of the acrylic we carry is cast acrylic, which is made by pouring liquid acrylic into molds. These molds are designed to produce a certain thickness, but because of how the material settles and cures, some variation is totally normal. In fact, the industry standard allows for up to a 30% variance in thickness. That means a sheet labeled as 1/8" might not be exactly that... sometimes it could be a little thicker or thinner.

If you're creating designs that require a snug fit; like slotted stands or layered pieces, this variance matters. That’s why we always recommend using digital calipers to measure each sheet before cutting. It’s a must-have tool for makers working with precision projects.

What About Length and Width?

Just like thickness, length and width can vary too. Standard mold sizes are typically 24" x 48", 48" x 72", or 48" x 96", but when those large sheets are cut down, the final dimensions can be slightly different due to something called saw kerf, which is the material lost during cutting.

Add in the fact that decorative and specialty acrylic often come from different manufacturers with their own mold sizes, and you'll start to see why no two sheets are exactly the same.

We occasionally get questions about why some acrylic sheets seem shorter than others, and this is usually the reason. For our Glowforge-sized sheets, we standardize the width to 18 inches, so that’s the minimum you can always count on. That said, we often cut a little generously, so many sheets will arrive measuring closer to 19 inches.

If you ever notice one sheet in your stack is slightly shorter than the rest, it’s most likely just a true 18-inch sheet. No worries, it still meets our standard! We’d always rather you be pleasantly surprised with a little extra than be let down by less.