Choosing the wrong thickness of acrylic is one of the most common mistakes people make. Go too thin and the sheet bows, flexes or cracks under stress. Go too thick and you’re spending more than you need to and making the job harder than it should be. The right thickness depends entirely on what you’re using it for, how big the panel is and how much support it has.
We sell clear acrylic from 2mm right up to 30mm, and every thickness has its place. This guide cuts through the guesswork and matches each one to the projects it’s actually suited for.
2mm: Light Duty and Budget Projects
The thinnest sheet in our range and the most affordable. 2mm acrylic is flexible, easy to cut with a Stanley knife and works well for small panels where rigidity isn’t critical. It’s a popular choice for picture frames, small craft projects, point-of-sale holders and lightweight protective covers. It’s also the go-to for budget secondary glazing on smaller windows, though it can bow on anything wider than about 600mm. If you need the panel to sit completely flat without any support behind it, step up to 3mm or 4mm.
3mm: The All-Rounder
This is our most popular thickness and for good reason. 3mm strikes a solid balance between rigidity, weight and cost. It’s stiff enough for greenhouse panels, shed windows, secondary glazing on standard-sized windows, indoor signage, photo frames and light display work. You can still score and snap it with a knife for straight cuts, which makes it genuinely DIY-friendly. For panels up to about 1 square metre with frame support on all edges, 3mm handles the job well.
4mm-5mm: The Step Up
When you need a bit more substance. 4mm is the thickness we recommend for secondary glazing if you want panels that sit perfectly flat with no flex whatsoever. It’s also the sweet spot for kitchen splashbacks, as thinner sheets can sometimes show adhesive through the material. 5mm adds further rigidity and is a strong choice for larger signage panels, sneeze screens, table top protectors, pergola roofing and anywhere the acrylic needs to span a gap without bowing. At 5mm and above, you’ll need a saw rather than a knife for cutting.
6mm-8mm: Structural and Load-Bearing
Once you move into this range, acrylic starts performing as a genuine structural material. 6mm works for larger window replacements, outdoor signage exposed to wind, protective barriers and counter screens in commercial settings. 8mm is where you’d look for furniture applications like small shelves or coffee table tops, aquarium panels for tanks up to about 100 litres and machine guards in workshop or industrial environments. These thicknesses are noticeably heavier and require power tools for cutting, but the rigidity and impact resistance justify the step up for demanding applications.
10mm-12mm: Heavy Duty
This is specialist territory. 10mm acrylic suits larger aquariums, architectural glazing, heavy-duty display cases and shelving that needs to support real weight without flexing. 12mm takes that further for applications where maximum strength matters, including security glazing, large format retail displays and load-bearing furniture like tabletops spanning 800mm or more. At these thicknesses, the material is rigid, substantial and genuinely tough.
15mm-30mm: Industrial and Architectural
The thickest sheets in our range are used for large-scale architectural glazing, industrial machine guards, aquarium builds above 200 litres and bespoke furniture where the thick edge of the acrylic is part of the design. These panels are heavy, require professional cutting equipment and are typically specified by fabricators, architects or engineers working to precise load requirements. If you’re working at this end of the scale, you likely already know your thickness needs. If not, get in touch and we can advise based on your specific project.
Quick Reference
Picture frames and crafts: 2-3mm. Greenhouse and shed glazing: 3-4mm. Secondary glazing: 3-5mm. Signage (indoor): 3mm. Signage (outdoor): 5-6mm. Splashbacks: 4-5mm. Sneeze screens and barriers: 4-6mm. Table top protectors: 5-8mm. Shelving: 8-12mm. Aquariums (small to medium): 8-12mm. Architectural glazing: 10-30mm.
Still not sure? The simplest rule is this: if the panel is well-supported on all edges, you can go thinner. If it needs to span a gap or take any load, go thicker. And when in doubt, stepping up one thickness costs relatively little but makes a real difference to performance.