Perspex vs Acrylic: Are They the Same Thing? A Straight-Talking UK Buyer's Guide
If you've spent ten minutes shopping for a splashback, a shelf or a shed window, you've probably seen the same sheet described as "Perspex" on one site and "acrylic" on another - often at wildly different prices. It's a fair thing to be suspicious about. So here's the honest version, written for people who just want to buy the right sheet without being talked at.
Acrylic is the everyday name for a plastic called polymethyl methacrylate, usually shortened to PMMA. It's a rigid, glass-clear thermoplastic that's been around since the 1930s and turns up in everything from aquariums to aircraft canopies. According to the British Plastics Federation, PMMA is prized for its optical clarity - it transmits more visible light than glass - along with good weathering, decent impact resistance, and the ability to be cut, drilled, bent, and polished with fairly ordinary tools.
That's the material. Every acrylic sheet you'll find in a UK plastics shop is PMMA at its core.
Perspex is a trade name. It's owned by Perspex Distribution, part of the German chemicals group Röhm, which also produces the Plexiglas brand you'll see mentioned in older DIY guides and in Europe. Both are essentially the same category of product: high-quality cast PMMA sheet made to controlled specifications.
So when a supplier says "Perspex," they should be selling you genuine Perspex-branded sheet. When they say "acrylic," they could be selling you anything from a premium cast panel to a thin, budget extruded sheet from a generic supplier. The label matters less than knowing which type of acrylic you're actually holding.
Cast Acrylic vs Extruded Acrylic
This is the split that actually affects how your sheet performs, and it's the one most retailers gloss over.
How each is made - briefly
Cast acrylic is made by pouring liquid PMMA between two sheets of glass and letting it cure. It's a slow, batch-based process. The result is a sheet with excellent optical clarity, higher molecular weight and better dimensional stability. It machines cleanly, laser cuts with a polished edge and holds paint and print well.
Extruded acrylic is made by pushing molten PMMA through a die in a continuous run - more like a pasta machine than a baking tray. It's cheaper to produce, has very consistent thickness, and is easier to thermoform (bend with heat). It's softer than cast, though, so it scratches more readily and doesn't machine quite as cleanly.
Comparison table
For anything you'll look at every day - a kitchen splashback, a coloured wall panel, a piece of shop signage - cast is worth the extra. The finish is deeper, the colour is truer, and it holds up to cleaning without hazing. For temporary screens, protective covers, or shapes you need to heat-bend at home, extruded does the job for less.
Our own acrylic splashbacks are made from cast sheet for exactly these reasons - the surface behaves better behind a hob and under repeated wiping.
Why Perspex Costs More
A Perspex-branded cast sheet typically carries a premium of anywhere from 20% to 50% over a generic cast acrylic of the same thickness. You're paying for:
Consistent, batch-controlled manufacturing to Röhm's tolerances
Reliable colour matching if you're ordering multiple sheets over time
Proper certification and traceability, which matters for commercial and architectural jobs
UV-stabilised grades that hold their colour outdoors for longer
Any job where the sheets need to match perfectly across a project - say, matching splashback panels in a show home, or replacement glazing in a listed building - is a good reason to specify Perspex by name. Anything client-facing where you can't afford a colour mismatch on a re-order is another.
For a single splashback in your own kitchen, a shelf in your garage, or a one-off craft project, a good-quality generic cast acrylic from a reputable UK supplier will look and perform effectively identically. Paying the brand premium buys you consistency you'll never notice.
Which One Should You Buy For?
Kitchen and bathroom splashbacks
Cast acrylic, every time. It resists heat better than extruded, cleans more easily and keeps its colour under years of steam and cooking. Whether you go for a plain white panel or a bold coloured acrylic splashback, the material underneath should be cast. Extruded panels marketed as "budget splashbacks" tend to show cleaning marks within a year.
Shelves and display
For clear or lightly loaded display shelves, either works. If the shelf will hold anything with weight - books, bottles, a home speaker - cast holds its shape better over time and is less prone to creep (slow sagging under load).
Signage
Cast for backlit signs, laser-cut lettering and anything with a polished visible edge. Extruded for large flat panels that will be printed on and viewed from a distance, where the cost saving stacks up on a big job.
DIY glazing and craft
Extruded is the friendlier choice for hobbyists - cheaper if you make a mistake, and easier to bend over a heat gun for curved projects. If you need a small pane cut to fit a shed window or picture frame, ordering acrylic sheets cut to size will usually be less hassle than buying oversized and trimming at home.
How to Check What You're Being Sold
Suppliers who take their materials seriously will state the type clearly. Look for:
The word "cast" or "extruded" in the product description, not just "acrylic sheet"
A named brand (Perspex, Plexiglas, Altuglas, Lucite) if cast is being sold at a premium
A thickness tolerance figure - cast is looser, extruded is tighter, and honest suppliers publish it
A protective film on both sides of the sheet, ideally with the manufacturer's name printed on it
If a listing just says "acrylic sheet" with no other detail and the price looks too good, it's almost certainly generic extruded - which is fine if that's what you need, but not if you're paying cast prices for it.
Common Mistakes When Buying "Perspex" Online
Assuming every "Perspex" listing is genuine Perspex. Plenty of eBay and marketplace sellers use the word as a generic synonym for acrylic. If it isn't from a specialist plastics stockist, treat the brand claim with a pinch of salt.
Buying on thickness alone. A 5 mm extruded sheet and a 5 mm cast sheet look identical on a listing but behave very differently once you cut, drill or install them.
Ordering slightly oversized to "trim at home." Acrylic chips and cracks easily without the right blade. Ordering cut to size from the supplier avoids most DIY disasters.
Skipping the protective film check. Sheets sold without film on both faces have often been sitting around a warehouse getting scuffed. The film is your quality indicator as much as your fitting aid.
Forgetting about UV grade for outdoor use. Standard interior acrylic will yellow outdoors over a few years. If it's going outside, ask for UV-stabilised.
Expert Tips
Peel the protective film only once the sheet is in position. It's the single easiest way to keep the finish factory-fresh.
For coloured splashbacks, order a small offcut or sample before committing. Colour on a screen and colour on a wall behind an LED strip are rarely the same thing.
If you're cutting at home, use a fine-toothed blade and go slow. Heat is the enemy - a fast blade melts the edge and welds the cut back together.
Clean with warm soapy water and a soft microfibre cloth. Glass cleaner, kitchen sprays and anything with ammonia will haze the surface over time.
Store spare sheets flat, not leaning. Acrylic remembers a bow, especially in a warm garage.
Final Thoughts
The Perspex-vs-acrylic argument isn't really an argument at all - it's a question of whether you need branded cast sheet, generic cast sheet or cheaper extruded sheet for the job in front of you. Once you know which of those three you're buying, the price differences make sense and the marketing waffle stops mattering.
For most kitchen and bathroom work, a good cast acrylic panel - branded or otherwise - will outlast trends, clean up easily and look considerably better than a bargain extruded sheet that came in a nondescript box. Buy the material that suits the job, from a supplier who tells you exactly what it is, and you'll rarely go wrong.
FAQs
What's the difference between PMMA and acrylic?
None, in practical terms. PMMA is the technical name for the polymer; acrylic is the everyday name for sheet products made from it.
Is Perspex the same as Plexiglas?
Both are trade names for cast PMMA sheet made by Röhm. The brand name used depends on the market - Perspex in the UK, Plexiglas across much of Europe.
Cast or extruded acrylic - which is better?
Cast for anything visible, decorative, or long-term. Extruded for budget, thermoforming or short-term uses. Neither is universally "better" - they're different products at different price points.
Can I use extruded acrylic as a splashback?
You can, but you'll regret it behind a hob. Extruded is softer, marks more easily under cleaning, and has lower heat tolerance than cast. Cast acrylic is the sensible choice for kitchens.
Where can I buy genuine Perspex in the UK?
Through Perspex Distribution's authorised stockists, and via established plastics specialists who publish the brand and grade clearly on their listings.
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