Thickness is the most consequential specification decision when ordering cast acrylic. Too thin and a panel deflects under load or shatters on impact. Too thick and you add unnecessary weight, cost, and fabrication complexity. This guide covers the full range from 1mm to 200mm, with specific guidance for common interior, architectural, and industrial applications.
What Thickness Controls
Sheet thickness governs four things simultaneously: structural rigidity, impact resistance, optical depth, and weight. Acrylic has a density of 1.19 g/cm³ — roughly half that of glass at the same dimensions. Rigidity scales with the cube of thickness: a 6mm sheet is not twice as stiff as a 3mm sheet — it is approximately 8× stiffer. This non-linear relationship means moving up one or two millimetres often delivers dramatically better structural performance.
1mm to 3mm — Lightweight and Decorative
1–2mm
These gauges are used for decorative overlays, flexible display inserts, light covers, and protective facings where structural load is absent. At 1mm, cast acrylic retains moderate flexibility and can be cold-bent to gentle radii. Not suitable for spanning applications.
3mm
The most widely used starting gauge for DIY and light commercial work. Suitable for picture frames, small sign faces, shelf inserts, cabinet glazing inserts, and light window glazing in protected locations. A 3mm sheet spanning more than 400mm without support will noticeably deflect in warm conditions — plan intermediate supports accordingly. At ISO 7823-1 tolerance, a 3mm nominal sheet may measure between 2.3mm and 3.7mm.
4mm to 12mm — General Purpose
5–6mm
A meaningful step up from 3mm. A 6mm sheet is approximately 8× stiffer than a 3mm sheet of the same span. Suitable for small display cases, cabinet doors, window panels to approximately 600mm unsupported span, and protective machine guards. Polishes cleanly and accepts solvent bonding with strong joint results.
8mm
Standard for retail display cases, interior partition panels, cabinet side panels, and shelving under moderate loads. A reliable all-round thickness for professional interior fit-outs and light commercial fabrication.
10mm
Enters structural territory. Suitable for aquariums to approximately 400mm water depth, load-bearing shelf panels to 900mm spans, and elements in high-traffic environments. At 10mm, polished edges begin to develop the prismatic optical depth that makes acrylic visually distinctive.
12mm
A benchmark for structural panels, machine guards, and architectural glazing in sheltered conditions. Polished edges at 12mm produce a pronounced prismatic effect — multiple colours refracted through the depth — that is a recognised design detail in high-end furniture and display work.
15mm to 50mm — Furniture and Architecture
At 15mm, cast acrylic begins to read as a material in its own right rather than a glass substitute. The mass, edge depth, and optical clarity at this gauge are the reasons designers specify cast acrylic for statement furniture — tabletops, credenzas, bar fronts, and bespoke shelving units. This is the standard thickness for bespoke interior furniture in Singapore's high-end residential and hospitality market.
20mm is used for structural aquariums to approximately 800mm water depth, architectural fins, and heavy-duty machine enclosures. Above 20mm, specialist routing and bonding equipment is required — home workshop fabrication becomes difficult. At 25–50mm, panels are used for museum-quality display cases, premium furniture, and architectural elements where the optical depth of the material is part of the design intent.
Above 50mm — Specialist and Industrial
Above 50mm, cast acrylic enters sculptural and industrial territory. Blocks and slabs in this range are used for optical components, decorative sculptures, large public aquarium panels, and precision engineering blanks where the material is machined to final form. At 200mm, a single standard-format sheet weighs several hundred kilograms. These are specialist procurement items requiring engineering review and extended lead times.
Weight Reference
Acrylic density: 1.19 g/cm³. Weights below are for a standard 2440 × 1220mm sheet.
| Thickness | Sheet weight (2440×1220mm) | Weight per m² |
|---|---|---|
| 3mm | ~5.3 kg | 1.8 kg/m² |
| 5mm | ~8.9 kg | 3.0 kg/m² |
| 6mm | ~10.7 kg | 3.6 kg/m² |
| 8mm | ~14.2 kg | 4.8 kg/m² |
| 10mm | ~17.8 kg | 6.0 kg/m² |
| 12mm | ~21.4 kg | 7.1 kg/m² |
| 15mm | ~26.7 kg | 8.9 kg/m² |
| 20mm | ~35.6 kg | 11.9 kg/m² |
Factor weight into mounting hardware specification — particularly for vertical panel installations and overhead elements. Acrylic at half the weight of glass still requires engineered fixings at larger dimensions.
Quick Reference by Application
| Application | Recommended Thickness |
|---|---|
| Decorative overlays, flexible covers | 1–2mm |
| Picture frames, small signs, cabinet inserts | 3mm |
| Display cases, cabinet doors, window panels | 5–6mm |
| Retail displays, interior partitions, shelving | 8mm |
| Load-bearing shelves, aquariums to 400mm depth | 10–12mm |
| Structural furniture, bar fronts, tabletops | 15mm |
| Statement furniture, large aquariums | 20–25mm |
| Heavy structural, bespoke architectural | 30–50mm |
| Optical, sculptural, industrial blocks | 50–200mm |
Find your thickness.
We supply cast acrylic from 1mm to 200mm in three standard sheet sizes. Use the configurator to select your specification, or contact us for guidance on a specific project.