Short answer: Yes. Plexiglass is the everyday name for acrylic sheet, a clear plastic called PMMA (polymethyl methacrylate). Plexiglas (one s) is a trademark Otto Röhm registered in 1933; Acrylite, Perspex, Lucite, Optix, and Altuglas are other makers' brand names for the same material. What matters is whether the sheet is cast or extruded, its thickness, and its grade, not the name on the film.
What acrylic actually is
Acrylic is a plastic made from methyl methacrylate. Its chemical name is polymethyl methacrylate, shortened to PMMA. It came to market as sheet in the 1930s as a lighter, shatter-resistant alternative to glass, and it's been used for aircraft canopies, signs, aquariums, and picture frames ever since. Every product on this page is PMMA.
Because several companies made it early on, it picked up several brand names, and some of them turned into everyday words. “Plexiglass” is to acrylic what “Kleenex” is to tissues.
Key facts
- Same material: clear PMMA sheet from the major makers has a specific gravity of 1.19 and transmits 92% of visible light (Acrylite and Optix data sheets).
- Plexiglas was entered in the trademark register by Dr. Otto Röhm on August 9, 1933. Röhm still owns it.
- Acrylite is the name Röhm's sheet is sold under in the Americas; the same sheet is sold as Plexiglas in Europe, Asia, Africa, and Australia.
- Perspex has been a British cast acrylic brand since 1934.
- Optix is Plaskolite's extruded acrylic, common in North American home centers.
Plexiglas, Acrylite, Perspex, Lucite, Optix: what's the difference?
| Name | What it is |
|---|---|
| Plexiglas (one s) | The original trademark, registered by Röhm in Germany in 1933. Röhm's sheet uses the name outside the Americas. In the Americas, Trinseo uses the Plexiglas name for acrylic resins and sells Altuglas elsewhere. |
| Plexiglass (two s's) | The generic, everyday spelling. Not a brand; people use it for any clear plastic sheet. |
| Acrylite | Röhm's brand for acrylic sheet in the Americas, offered as cast (GP) and extruded (Premium FF) lines, plus framing, frosted, and LED grades. |
| Perspex | A British cast acrylic brand made since 1934, and the common word for acrylic in the UK, Australia, and much of the Commonwealth. |
| Lucite | A brand that started at DuPont in the US. Now used mainly for acrylic resins and cast sheet, and as a style word for clear furniture. |
| Optix | Plaskolite's extruded acrylic, sold from 0.040 to 1 in. thick and stocked in many home improvement stores. |
| Altuglas | Trinseo's acrylic brand outside the Americas. |
| Acrylic glass, acrylic sheet | Plain descriptions of the same material. |
Ownership and product lines change over time, so check the current manufacturer's data sheet if you need exact properties. The brand tells you who made it; it doesn't tell you whether it's better.
Does the brand matter?
Much less than the type of sheet. Two brands of cast acrylic behave almost identically. A cast sheet and an extruded sheet from the same brand behave quite differently:
- Cast acrylic engraves bright frosty white, machines cleanly, resists crazing, takes a little more heat (Acrylite cast is rated for 180 °F continuous service), and costs more.
- Extruded acrylic costs less, holds its thickness more evenly, and glues faster, but engraves clearer, crazes more easily, and is rated lower for heat (160 °F for Acrylite extruded).
Read the full comparison in cast vs extruded acrylic. Grade matters too: there are UV-filtering (such as Acrylite OP3), non-glare (Acrylite P99, Optix NG), abrasion-resistant, and impact-modified (Plaskolite Duraplex) acrylics, each made for a specific job.
What isn't acrylic (even if it's on the same shelf)
Stores often stock several clear plastics side by side, and the labels can be vague. These look similar but are different materials:
- Polycarbonate (brands such as Lexan, Makrolon, Tuffak). Much tougher, but softer, scratches more easily, costs more, and doesn't laser cut well. Acrylic vs polycarbonate.
- PETG (brands such as Vivak). Tough and easy to thermoform, common for face shields and vacuum-formed parts. Acrylic vs PETG.
- Polystyrene. The thin, inexpensive “clear plastic” in many cheap picture frames. Brittle and yellows faster than acrylic.
For a wider comparison, see acrylic vs other plastics.
What to ask for in a store
- Ask for acrylic by name and check the film or label for “acrylic” or “PMMA”. If the label says polycarbonate, styrene, or PETG, it isn't acrylic.
- Ask whether it's cast or extruded. Most thin sheet in home stores is extruded. If you plan to engrave it, look for cast.
- Check the real thickness. Store sheet is often sold by decimal sizes such as 0.093 in. or 0.220 in., not true 1/8 or 1/4 in. What acrylic sizes actually measure.
- Ask about cutting. Scoring and snapping works for thin acrylic in straight lines; curves, holes, and clean edges are much easier when the sheet is cut by laser or router.
Or skip the store: order acrylic cut to your exact size, with the edges finished and the holes drilled, and see your price instantly in the calculator.
Questions
Is it plexiglass or plexiglas?
Plexiglas, with one s, is the trademark. Plexiglass, with two, is the generic spelling most people use for any acrylic sheet. Both refer to the same material.
Is plexiglass a type of glass?
No. It's a plastic. It's called “acrylic glass” because it looks like glass, but it weighs about half as much, resists breaking several times better, and scratches more easily.
How can I tell acrylic from polycarbonate?
Check the film or label first. On a scrap, acrylic snaps when bent sharply while polycarbonate bends a long way without breaking; polycarbonate also scratches and dents more easily. A laser-cut edge is another clue: acrylic comes out glossy, polycarbonate brown and charred.
Is Perspex the same as Plexiglas?
Yes, both are cast acrylic (PMMA) from different makers. “Perspex” is simply the word most people in the UK and Australia use, the way Americans say “plexiglass”.
Is Lucite the same as acrylic?
Yes. Lucite is a brand of acrylic. “Lucite furniture” and “Lucite boxes” are just clear acrylic, usually thick cast sheet with polished edges.