Polyurethane Weight Calculator
Calculate PU sheet, rod, and tube weight — cast Shore 60A through 95A, rigid foam, and rigid solid grades
Polyurethane Weight Calculator
Calculation Results
Grade Quick Reference
Formula Used
Polyurethane Grade Specifications
Density values for cast polyurethane per ASTM D792 / ISO 1183. Shore A hardness per ASTM D2240. Tensile strength and elongation at break per ASTM D412. Abrasion resistance rated qualitatively relative to natural rubber (NR = 100).
| Grade | Density (g/cm³) | Hardness | Tensile Strength | Elongation at Break | Abrasion Resistance |
|---|---|---|---|---|---|
| Cast PU — Shore 60A | 1.10 | 60 Shore A | 8–20 MPa | 500–700% | Excellent |
| Cast PU — Shore 90A | 1.14 | 90 Shore A | 30–45 MPa | 350–500% | Excellent |
| Cast PU — Shore 95A | 1.16 | 95 Shore A | 30–45 MPa | 250–400% | Outstanding |
| Rigid PU Foam — Low Density | 0.08 | Rigid cellular | 0.1–0.3 MPa | <5% | Low |
| Rigid PU — Solid | 1.20 | ~60 Shore D | 30–55 MPa | 5–20% | Very Good |
Standards: Shore A hardness per ASTM D2240. Tensile strength and elongation at break per ASTM D412. Density per ASTM D792 / ISO 1183. Abrasion resistance per DIN 53516 (relative to NR = 100). Actual values vary by specific formulation and supplier — confirm with material data sheet.
Understanding the Shore Hardness Scale for Polyurethane
Polyurethane is unique among engineering materials in that it spans from soft rubber-like elastomers to hard rigid plastics — all within the same polymer family. The Shore hardness scale is the primary way to specify which region of this range you need. Hardness directly affects both density and mechanical behavior.
Cast PU — Shore 60A (Flexible)
Soft, highly flexible elastomer with exceptional elongation (500–700%). Similar in feel to a car tire sidewall. Ideal where the part must deflect under load and return to shape — vibration isolation mounts, flexible gaskets, cushioning pads, and bumpers.
- Density: 1.10 g/cm³
- Best for: vibration damping, flexible seals, cushioning
- Highest elongation of the cast grades
Cast PU — Shore 90A (Medium)
The most widely stocked cast polyurethane hardness. Firm but still elastomeric — comparable to a hard rubber eraser or a skateboard wheel. Excellent balance of load-bearing capacity, abrasion resistance, and resilience. The default choice for industrial wheels, conveyor rollers, and general wear parts.
- Density: 1.14 g/cm³
- Best for: wheels, rollers, wear pads, squeegees
- Best all-around abrasion resistance for the cast grades
Cast PU — Shore 95A (Firm)
Near the upper limit of the Shore A scale — approximately equivalent to Shore 45D. Firm, tough, and outstanding in abrasion resistance. Lower elongation than softer grades but significantly higher load capacity. Used where the part must resist cutting, gouging, or abrasive wear under heavy loads.
- Density: 1.16 g/cm³
- Best for: scrapers, cutting boards, wear liners, die pads
- Outstanding abrasion resistance — among the best of any elastomer
Rigid PU — Solid and Foam Grades
Rigid solid PU (1.20 g/cm³, ~Shore 60D) behaves more like a hard plastic than an elastomer — used for structural load plates, jig components, and machinable tooling blocks. Rigid PU foam (0.08 g/cm³) is at the opposite extreme: a lightweight cellular material used for thermal insulation panels, buoyancy modules, and core structures in composite sandwich panels.
- Solid: 1.20 g/cm³ — structural, machinable
- Foam: 0.08 g/cm³ — insulation, buoyancy, lightweight cores
- Foam is approximately 15× lighter than solid cast PU
Standard Stock Sizes
Common stock dimensions for cast polyurethane sheet and rod. Custom cast sizes and thicknesses are available from most PU suppliers — confirm availability before ordering.
S Sheet Stock
Standard sheet size: 24" × 48" or 36" × 36". Common thicknesses:
Metric equivalent (approx): 6 mm, 10 mm, 13 mm, 19 mm, 25 mm, 38 mm, 51 mm, 76 mm, 102 mm
R Rod Stock
Standard rod length: 12" to 36" depending on diameter. Available diameters:
Metric equivalent (approx): 25 mm, 38 mm, 50 mm, 63 mm, 75 mm, 100 mm, 125 mm, 150 mm
Polyurethane Applications
Cast polyurethane is the material of choice wherever abrasion resistance, load capacity, and resilience are required simultaneously. No other single material combines these properties as effectively at comparable cost.
Wheels & Rollers
- Fork truck and pallet jack wheels
- Conveyor drive and idler rollers
- Caster wheels for industrial carts
- Printing press rollers
- Press nip rollers
Wear Parts & Gaskets
- Wear liners and abrasion pads
- Squeegees and doctor blades
- Hydraulic and pneumatic seals
- Screen printing squeegees
- Die cutting pads
Vibration & Impact
- Machinery vibration isolation mounts
- Bumpers and end stops
- Impact buffers for press equipment
- Anti-vibration pads under equipment
- Shock absorber elements
Polyurethane vs Rubber: Which Should You Use?
Polyurethane and rubber are both elastomers but differ significantly in abrasion resistance, oil resistance, and load-bearing capacity. PU typically outperforms rubber in industrial wear applications; rubber retains advantages in low-temperature performance and certain dynamic sealing applications.
| Property | Polyurethane (90A) | Natural Rubber |
|---|---|---|
| Density (g/cm³) | 1.14 | 0.92–0.96 |
| Abrasion Resistance | Outstanding | Good |
| Oil & Fuel Resistance | Very Good | Poor |
| Load-Bearing Capacity | Excellent | Moderate |
| Low-Temperature Flex | Good (−40°C) | Excellent (−60°C) |
| UV Resistance | Poor (standard grades) | Poor |
| Cut & Tear Resistance | Excellent | Good |
| High-Volume Part Cost | Moderate–High | Lower |
Choose Polyurethane when:
- Abrasion wear is the primary failure mode
- Oil, grease, or hydrocarbon exposure is expected
- High point loads require good load distribution
- Cut or puncture resistance is required
Choose Rubber when:
- Very low temperatures (below −40°C) are required
- High-volume compression molded parts reduce cost
- Dynamic sealing applications with specific swell characteristics
- Electrical insulation properties are important
Need HDPE weight for wear pads? Use our HDPE Weight Calculator.
Processing Notes: Cast vs Injection Molded PU
Polyurethane can be processed by casting, reaction injection molding (RIM), and conventional injection molding — each with different property outcomes and economic trade-offs. Moisture sensitivity is a critical handling factor for all PU processing.
Cast Polyurethane
- Process: Liquid prepolymer + curative poured into open molds at 60–120°C, cured 16–24 hours
- Best for: Low-to-medium volume, large parts, custom dimensions, prototype quantities
- Advantages: Low tooling cost, excellent property control, wide hardness range, large-format capability
- Limitations: Slow cycle time, labor-intensive, not suited to high-volume production
- Moisture sensitivity: Isocyanate components react with moisture — store sealed, use dry equipment
Injection Molded / RIM Polyurethane
- Process: RIM — two liquid components mixed and injected into a closed mold under low pressure; thermoplastic PU (TPU) can be injection molded conventionally
- Best for: High-volume production, complex geometries, automotive and consumer parts
- Advantages: Fast cycle times, good dimensional repeatability, suitable for large body panels
- Limitations: Higher tooling cost than cast, TPU grades have narrower hardness range than cast PU
- Moisture sensitivity: TPU pellets must be dried to <0.02% moisture before processing to prevent hydrolysis and splay defects
Important: Moisture and Isocyanate Safety
Isocyanates (MDI, TDI) used in PU casting are reactive with water and are respiratory sensitizers. Always work with adequate ventilation, use sealed containers, and follow supplier SDS requirements. Dried prepolymers and properly sealed systems significantly reduce exposure risk. Post-cured cast parts are inert and safe to handle normally.
Standards & Certifications
Polyurethane testing and material certification follows well-established ASTM standards. Understanding which standard applies to each property helps ensure your specification aligns with supplier documentation.
ASTM D412
Standard test methods for vulcanized rubber and thermoplastic elastomers — tension. Covers tensile strength, elongation at break, and tensile stress at specified elongation. The primary standard for mechanical property reporting of cast and molded polyurethane elastomers.
ASTM D2240
Standard test method for rubber property — durometer hardness. Covers Shore A (soft elastomers) and Shore D (harder materials) scales. Shore A is the standard hardness specification for cast polyurethane elastomers; Shore D is used for rigid polyurethane. The durometer reading is taken after a specified dwell time (instantaneous or 15-second).
DIN 53516 / ISO 4649
Abrasion resistance test using a rotating drum with standardized abrasive paper. Results reported as volume loss in mm³ relative to a standard reference rubber. Polyurethane typically shows 50–150 mm³ loss vs 200+ mm³ for natural rubber, confirming its superior abrasion resistance. Relevant when selecting PU for wear-critical applications.
Frequently Asked Questions
What is the density of polyurethane?
Cast solid polyurethane density ranges from 1.10 g/cm³ (Shore 60A, flexible) to 1.20 g/cm³ (rigid solid, ~Shore 60D). Hardness and density increase together as the urethane linkage content rises and plasticizer content falls. Rigid polyurethane foam is dramatically lighter at 0.05–0.10 g/cm³ because of its cellular structure. For weight calculations, always specify whether you are using solid cast or foam grades — the difference is a factor of 10 to 15 in density.
What is the difference between Shore A and Shore D hardness?
Shore A measures softer, flexible elastomers (0–100 scale) and is used for most cast polyurethane grades. Shore D measures harder materials and is used for rigid polyurethane and hard plastics. The scales overlap in the range of Shore 90A to Shore 95A, which corresponds to approximately Shore 40D to Shore 50D. Specifying Shore A is appropriate for flexible PU stock shapes; Shore D is used for rigid PU tooling and structural grades. Always confirm which scale your supplier uses when ordering.
How does polyurethane compare to rubber?
Polyurethane outperforms natural rubber and most synthetic rubbers in abrasion resistance (typically 3–5 times better by volume loss in DIN 53516 testing), oil and hydrocarbon resistance, cut resistance, and load-bearing capacity under static and dynamic loads. Rubber maintains advantages in very low temperature flexibility (below −40°C), high-volume compression molded part economics, and dynamic sealing applications where specific swell or compression set characteristics are required. For wheels, rollers, wear liners, and scrapers, polyurethane is almost always the superior choice.
Is polyurethane UV resistant for outdoor applications?
Standard aromatic polyurethanes (most cast stock grades) have poor UV resistance and will yellow, chalk, and lose mechanical properties with sustained outdoor sun exposure. Aliphatic polyurethane formulations resist UV degradation and are used for coatings and outdoor applications where appearance matters. UV-stabilized cast grades with light stabilizer additives are available but less common than standard aromatic grades. For outdoor wear parts where aesthetics are secondary, standard PU may still be acceptable if the functional properties are retained despite surface discoloration — confirm with your supplier.
What is the difference between polyurethane foam and solid cast polyurethane?
Rigid polyurethane foam (0.05–0.10 g/cm³) is a closed-cell cellular material produced by incorporating blowing agents into the PU reaction. It is used for thermal insulation panels (construction, refrigeration), buoyancy modules, and lightweight structural cores in composite sandwich panels. Solid cast polyurethane (1.10–1.20 g/cm³) is a fully dense elastomeric material used for wear parts, rollers, and load-bearing components. Foam is 10–15 times lighter per unit volume than solid cast PU. The calculator above supports both — use the grade dropdown to select the correct type for your application.
How do I calculate polyurethane weight?
Polyurethane sheet weight = Length (mm) × Width (mm) × Thickness (mm) ÷ 1000 × Density (g/cm³). Rod weight = π × (D ÷ 2)² × Length (mm) ÷ 1000 × Density. For a 50 mm diameter × 300 mm Shore 90A PU rod (1.14 g/cm³): π × 25² × 300 ÷ 1000 × 1.14 = 589.0 × 1.14 = 671 g. Rigid polyurethane foam (0.08 g/cm³) gives only 47 g for the same shape — 14 times lighter than solid cast. Select your grade and shape in the calculator above for instant results in metric or imperial.