Plexiglass Weight Calculator
Calculate acrylic sheet and rod weight for all PMMA grades — cast, extruded, UV-resistant, and impact-modified
Acrylic Weight Calculator
Calculation Results
Grade Quick Reference
Formula Used
Acrylic Grade Specifications
Density per ASTM D792 / ISO 1183. Tensile strength per ASTM D638. Maximum service temperature for continuous use.
| Grade | Density (g/cm³) | Tensile Strength | Max Temp | Chemical Resistance | FDA |
|---|---|---|---|---|---|
| Cast Acrylic — Standard | 1.19 | 72 MPa | 93°C / 200°F | Good | Yes* |
| Extruded Acrylic | 1.18 | 69 MPa | 79°C / 175°F | Good | Varies |
| UV-Resistant Acrylic | 1.19 | 72 MPa | 93°C / 200°F | Good | Yes* |
| Impact-Modified Acrylic | 1.14 | 55 MPa | 82°C / 180°F | Good | Varies |
Standards: ASTM D4802 (acrylic plastic sheet). Density per ASTM D792. *FDA compliance per 21 CFR 177.1010 (cast sheet); extruded and impact grades vary by formulation — confirm with supplier. RoHS compliant across all grades.
Which Acrylic Grade Should You Use?
Plexiglass and acrylic are available in several distinct forms. The right choice depends primarily on how the sheet will be fabricated and what optical or structural properties matter most.
Cast Acrylic — Standard
The premium grade. Cast between glass plates in a batch process, resulting in superior optical clarity, better chemical resistance, and a higher heat distortion temperature (93°C vs 79°C for extruded). Choose for display cases, aquariums, optical diffusers, machine guards, and any application where appearance matters.
- Density: 1.19 g/cm³
- Best choice for: glazing, display, signage, optical work
- Slightly more brittle than extruded — scores and snaps cleanly
Extruded Acrylic
Made by continuous extrusion. Slightly lower density (1.18 g/cm³) and a lower heat distortion point (79°C), but offers tighter thickness tolerances and responds better to thermoforming at lower temperatures. The standard choice for bent signs, vacuum-formed parts, and high-volume fabrication where cost matters more than optical perfection.
- Density: 1.18 g/cm³
- Best choice for: thermoformed parts, bent signage, fabricated enclosures
- Softer surface — more prone to scratching than cast
UV-Resistant Acrylic
Cast acrylic with UV stabilizers that resist yellowing and surface degradation in direct sunlight. Properties and density are identical to standard cast acrylic. Required for outdoor glazing, greenhouse panels, skylights, and any exterior signage exposed to extended UV. Standard acrylic yellows noticeably within 2–3 years outdoors without UV stabilization.
- Density: 1.19 g/cm³ — same as cast for weight purposes
- Best choice for: outdoor signage, skylights, greenhouse panels
- Premium cost over standard cast — justified by service life outdoors
Impact-Modified Acrylic
A rubber modifier is incorporated into the PMMA matrix, roughly doubling impact resistance at the cost of reduced optical clarity and lower density (1.14 g/cm³). Use when the part must resist breakage in handling or service. Not suitable for applications where clarity is paramount — the rubber phase causes slight haze.
- Density: 1.14 g/cm³ — noticeably lighter than standard grades
- Best choice for: point-of-purchase displays, machine guards, safety shields
- Reduced clarity vs cast — confirm acceptable haze level before specifying
Standard Stock Sizes
Common stock dimensions for acrylic sheet and rod. Standard sheet size is 48" × 96" (4 ft × 8 ft). Confirm availability and lead time with your supplier before ordering.
S Sheet Stock
Standard sheet size: 48" × 96". Available thicknesses:
R Rod Stock
Standard lengths: 4 ft and 8 ft. Available diameters:
Common Acrylic Applications by Industry
Acrylic's combination of optical clarity, weather resistance, and ease of fabrication makes it the default glazing and display material across many industries.
Display and Retail
- Display cases and showcases
- Cast acrylic sheet — optical clarity rivals glass at less than half the weight
- Point-of-purchase stands and holders
- Cast or impact-modified acrylic rod and sheet — polishes to a clear edge finish
- Illuminated signage and light diffusers
- Extruded acrylic sheet — consistent light diffusion, compatible with LED backlighting
Architecture and Construction
- Skylights and roof glazing panels
- UV-resistant cast acrylic — 50% lighter than glass, resists yellowing outdoors
- Greenhouse and cold frame panels
- UV-resistant acrylic sheet — high light transmission (92%), UV stabilized
- Interior partitions and privacy screens
- Cast acrylic sheet — available in clear, frosted, and colored formulations
Industrial and Safety
- Machine guards and safety shields
- Impact-modified acrylic — higher toughness than standard cast, visible through barrier
- Fluid level sight gauges
- Cast acrylic rod — transparent, chemical resistant to many oils and fuels
- Instrument and control panel windows
- Cast acrylic sheet — scratch-resistant surface, easy to clean
Marine and Aquatics
- Aquarium panels and tanks
- Cast acrylic sheet — glass-like clarity, UV resistant, lighter than glass for large builds
- Boat hatches, ports, and windshields
- UV-resistant acrylic — resists saltwater spray, maintains optical clarity over years
- Underwater viewing windows
- Thick cast acrylic plate — used in public aquariums at depths where glass would require impractical thickness
Acrylic vs Polycarbonate: Which Should You Choose?
Acrylic and polycarbonate are the two most commonly compared transparent sheet materials. Their densities are nearly identical (1.19 vs 1.20 g/cm³), so the choice is driven entirely by other properties.
Choose Acrylic When:
- + Optical clarity is paramount — acrylic transmits 92% of visible light vs 88% for PC
- + Long-term outdoor UV exposure is expected — uncoated acrylic significantly outperforms uncoated PC in yellowing resistance
- + Laser cutting is the primary fabrication method — acrylic cuts cleanly with a polished edge; PC does not cut as well with CO2 lasers
- + Cost is a constraint — acrylic is typically 30–50% less expensive than equivalent PC sheet
Choose Polycarbonate When:
- + Impact resistance is critical — PC is 30–40× more impact resistant than acrylic, used in riot shields and bulletproof glazing
- + Parts will be drilled, punched, or cold-bent in fabrication — PC is far more forgiving than acrylic in these operations
- + Higher service temperature is required — PC handles continuous use to 115°C vs 93°C for cast acrylic
- + Thin gauges must be formed without cracking — PC can be cold-bent to tight radii that would shatter acrylic
Weight note: For weight estimation purposes, acrylic (1.19 g/cm³) and polycarbonate (1.20 g/cm³) are essentially identical — a difference of less than 1%. Use our polycarbonate weight calculator to compare weights for your specific dimensions.
Processing and Machinability Notes
Acrylic machines well but requires different techniques than metals and some other plastics. These notes apply primarily to cast acrylic; extruded grades behave similarly.
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1
Laser cutting produces a flame-polished edge on cast acrylic
CO2 lasers cut cast acrylic cleanly and leave a clear, polished edge that requires no further finishing. This is the primary reason acrylic is preferred over polycarbonate for laser-cut display and signage work. Extruded acrylic cuts well but may show slight edge cloudiness compared to cast.
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2
Use O-flute (single-flute) router bits and high spindle speeds
Standard metal-cutting tools will melt acrylic rather than cut it. Single-flute O-flute bits at high RPM (18,000–24,000) with fast feed rates evacuate chips before heat builds up. Use a cooling air blast if possible. Dull tooling is the most common cause of cracking and melting during CNC routing.
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3
Thermoforming requires higher temperatures for cast vs extruded
Extruded acrylic softens at a lower temperature (around 150°C) than cast (around 170°C), making it easier to thermoform with simpler tooling. Cast acrylic forms less easily but holds tighter radii without optical distortion. For complex curves, extruded acrylic is the better choice.
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4
Solvent cementing works well — unlike polyolefins
Acrylic bonds readily with methylene chloride or purpose-formulated acrylic cements (IPS Weld-On range). The solvent dissolves both surfaces and creates a molecular bond. Capillary application (running solvent along a joint by surface tension) gives the cleanest results. Allow adequate cure time before stress-loading bonded joints.
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5
Acrylic is notch-sensitive — drill holes before assembly
Acrylic cracks preferentially from notches and stress concentrations. Always drill holes before assembly, use a reduced drill speed, and back the sheet with scrap material to prevent exit-side chipping. For screw fastening, use slotted holes rather than tight holes to allow thermal expansion — acrylic has a thermal expansion coefficient roughly 7× that of steel.
Standards and Certifications
Standard Specification for Poly(Methyl Methacrylate) Acrylic Plastic Sheet. Covers cast, extruded, and continuous-cast sheet grades with classification by type and group.
Acrylic and modified acrylic plastics permitted for use as articles or components of articles intended for food-contact use. Applies to cast sheet grades produced from compliant formulations.
All standard acrylic grades are RoHS compliant. PMMA does not contain restricted heavy metals or halogenated substances. Confirm with supplier for specialty formulations with additives.
Frequently Asked Questions
What is the density of plexiglass?
Plexiglass (cast PMMA acrylic) has a density of 1.19 g/cm³ (1190 kg/m³). Extruded acrylic is slightly lighter at 1.18 g/cm³. UV-resistant grades match cast at 1.19 g/cm³. Impact-modified acrylic is 1.14 g/cm³ — noticeably lighter due to the rubber modifier content. For shipping weight estimates, 1.19 g/cm³ is the correct value for standard cast sheet and most UV-resistant grades.
How do I calculate the weight of an acrylic sheet?
For metric dimensions: Weight (g) = Length (mm) × Width (mm) × Thickness (mm) ÷ 1000 × Density (g/cm³). For a 1000 mm × 600 mm × 6 mm cast acrylic sheet: (1000 × 600 × 6) ÷ 1000 × 1.19 = 3,600 cm³ × 1.19 = 4,284 g (4.284 kg). For imperial: multiply length × width × thickness (all in inches) × 0.0431 lb/in³ for cast acrylic to get weight in pounds. This calculator handles both systems automatically.
What is the difference between cast and extruded acrylic?
Cast acrylic is made by pouring liquid monomer between glass plates and curing it — a batch process that produces superior optical clarity, better chemical resistance, and higher heat resistance (93°C vs 79°C). Extruded acrylic is made by pushing molten resin through a die in a continuous process. Extruded sheet has tighter thickness tolerances (useful for precision fabrication), lower cost, and is easier to thermoform at lower temperatures. For most display and glazing work, cast is the preferred choice. For thermoformed parts and cost-sensitive applications, extruded is better.
Is acrylic lighter than polycarbonate?
In practice, no — they weigh nearly the same. Cast acrylic is 1.19 g/cm³ and polycarbonate is 1.20–1.22 g/cm³. The weight difference for equal-sized sheets is less than 2% — not a meaningful factor in material selection. The differences that matter are impact resistance (PC is 30–40× tougher), UV stability (acrylic is better without coatings), and cost (acrylic is cheaper). Use both calculators to compare weights for your specific dimensions.
How much does acrylic sheet weigh?
Cast acrylic (1.19 g/cm³) sheet weight per square foot by common thickness: 1/8" (3.175 mm) = 0.353 kg (0.778 lbs); 1/4" (6.35 mm) = 0.706 kg (1.556 lbs); 3/8" (9.525 mm) = 1.059 kg (2.334 lbs); 1/2" (12.7 mm) = 1.412 kg (3.111 lbs). A standard 4 ft × 8 ft sheet at 1/4" weighs approximately 22.6 kg (49.8 lbs). For 3 mm sheet: 0.380 kg per sq ft. Use the calculator above with your exact dimensions for any size or grade.