Polypropylene Weight Calculator
Calculate PP sheet and rod weight for all grades — homopolymer, copolymer, glass-filled, and FDA
PP Weight Calculator
Calculation Results
Grade Quick Reference
Formula Used
PP Grade Specifications
All density values per ISO 1183 / ASTM D-1505. Tensile strength per ASTM D638. Maximum service temperature for continuous use.
| Grade | Density (g/cm³) | Tensile Strength | Max Temp | Chemical Resistance | FDA |
|---|---|---|---|---|---|
| PP Homopolymer — General Purpose | 0.905 | 35 MPa | 100°C / 212°F | Excellent | No |
| PP Random Copolymer | 0.898 | 28 MPa | 90°C / 194°F | Excellent | No |
| PP Impact Copolymer | 0.905 | 25 MPa | 100°C / 212°F | Excellent | No |
| PP 30% Glass-Filled | 1.13 | 70 MPa | 120°C / 248°F | Good | No |
| PP Homopolymer — FDA Grade | 0.905 | 35 MPa | 100°C / 212°F | Excellent | Yes |
Standards: ASTM D4101 (PP material specification). Density per ISO 1183 / ASTM D-1505. FDA compliance per 21 CFR 177.1520. NSF 51 (food equipment) applicable to FDA Grade. RoHS compliant across all grades.
Which PP Grade Should You Use?
Polypropylene is available in several distinct grades with meaningfully different mechanical profiles. Getting the grade right matters both for weight estimation and for performance in the application.
PP Homopolymer — General Purpose
The baseline grade. Use when you need the stiffest, lightest, most chemically resistant unfilled PP. Best cost-to-performance ratio for indoor structural parts, tanks, and machined components that stay above -10°C.
- Density: 0.905 g/cm³
- Best choice for: chemical tanks, ductwork, machined brackets
- Avoid below -10°C — becomes brittle
PP Random Copolymer — General Purpose
A small amount of ethylene comonomer is added during polymerization. The result is slightly lower density (0.898), better clarity, and meaningfully improved impact resistance at low temperatures. The standard choice for packaging.
- Density: 0.898 g/cm³ — lightest unfilled PP grade
- Best choice for: food packaging, beverage containers, medical trays
- Lower service temperature limit: 90°C vs 100°C for homopolymer
PP Impact Copolymer — High Impact
A rubber phase dispersed in a homopolymer matrix provides the highest impact resistance of any unfilled PP. The trade-off is lower stiffness than homopolymer. Use for parts that must absorb repeated shock or operate in cold environments.
- Density: 0.905 g/cm³
- Best choice for: automotive bumpers, crates, outdoor furniture, pipe fittings
- Maintains impact resistance down to -20°C
PP 30% Glass-Filled
30% short glass fiber reinforcement doubles tensile strength to 70 MPa and raises the maximum service temperature to 120°C. Density increases to 1.13 g/cm³ — a 25% weight penalty vs unfilled grades. Worth it when stiffness and strength are the primary requirements.
- Density: 1.13 g/cm³ — significantly heavier than unfilled grades
- Best choice for: structural housings, brackets, automotive under-hood parts
- Lower impact resistance than unfilled grades — not for shock applications
PP Homopolymer — FDA Grade
Same mechanical properties and density as standard homopolymer (0.905 g/cm³), but produced from compliant raw materials and additives per 21 CFR 177.1520. Typically natural/white color. Meets NSF 51 for food equipment. Required for cutting boards, food processing components, and medical device housings that contact food or beverages.
- Density: 0.905 g/cm³ — same as standard homopolymer for weight purposes
- Best choice for: food processing equipment, dietary supplement packaging, medical device components
- FDA and NSF 51 compliance documented — request certificates from your supplier
Standard Stock Sizes
Common stock dimensions for PP sheet and rod. Confirm availability with your supplier before ordering.
S Sheet Stock
Standard sheet size: 48" × 96" (4 ft × 8 ft). Available thicknesses:
R Rod Stock
8 ft lengths up to 2" diameter. 4 ft lengths for 2.25" and larger. Available diameters:
Purple = 4 ft lengths only
Common PP Applications by Industry
Polypropylene is used across virtually every industry, but the grade selection varies significantly by application. These examples show the specific parts, not just the industry.
Chemical Processing
- Acid storage tanks
- PP Homopolymer sheet, welded construction — resists HCl, H₂SO₄, and most acids
- Scrubber internals and baffles
- PP Homopolymer rod and sheet — lightweight, chemically inert, easy to machine
- Chemical ductwork and fume hoods
- PP Homopolymer sheet — lightweight vs PVC, excellent chemical resistance
Food and Beverage
- Food processing cutting boards and wear strips
- PP FDA Grade sheet — NSF 51 compliant, easy to sanitize, USDA acceptable
- Beverage packaging caps and closures
- PP Random Copolymer — good clarity, food safe, sterilizable at low temperature
- Conveyor guide rails and slide beds
- PP FDA Grade rod — low friction, wear resistant, NSF compliant
Automotive
- Bumper fascias and body trim
- PP Impact Copolymer — absorbs impact without cracking, light weight advantage over steel
- Battery trays and underhood panels
- PP 30% Glass-Filled — stiff, heat resistant to 120°C, significant weight saving vs metal
- Door panel inserts and interior trim
- PP Impact Copolymer — good surface finish, low density, cost-effective in high volumes
Medical and Industrial Equipment
- Medical device housings and instrument cases
- PP FDA Grade — sterilizable, chemical resistant, lighter than most alternatives
- Pump housings and valve bodies
- PP Homopolymer — corrosion-free, lighter than metal, suitable for most fluid handling
- Structural brackets and mounting plates
- PP 30% Glass-Filled — replaces aluminum in low-to-moderate load applications
PP vs HDPE: Which Should You Choose?
PP and HDPE are often compared directly. Both are polyolefins with excellent chemical resistance and low density. The differences come down to stiffness, temperature performance, and processing behavior.
Choose PP When:
- + You need higher stiffness — PP homopolymer is roughly 30% stiffer than HDPE at equal thickness
- + Operating temperature reaches 90–100°C — PP handles higher heat than HDPE (60–80°C max continuous)
- + You need a living hinge — PP's fatigue resistance in thin flexure zones is unmatched
- + FDA compliance is required and you want the lightest food-safe plastic
- + Chemical tanks for acids — PP has better acid resistance than HDPE in concentrated applications
Choose HDPE When:
- + Impact resistance in cold environments matters most — HDPE maintains toughness to -40°C vs PP's -10°C limit (homopolymer)
- + You're fabricating marine or outdoor parts exposed to UV without painting — HDPE weathers better
- + Wear resistance is the priority — HDPE has better abrasion resistance for wear pads and guide strips
- + You need a weld-free large tank — HDPE rotomolded tanks are more common than PP in very large sizes
- + Cost is the deciding factor — HDPE is typically less expensive per pound than equivalent PP
Weight note: PP Homopolymer (0.905 g/cm³) and HDPE (0.950–0.965 g/cm³) are both lighter than water. A PP part will be 6–7% lighter than the same HDPE part — worth accounting for in shipping cost or weight-sensitive assembly work. Use our HDPE density comparison tool to compare polyethylene grades directly.
Processing and Machinability Notes
PP is a straightforward material to machine and fabricate, but a few properties require attention for clean results.
-
1
Use sharp tooling and high speeds
PP's low modulus means dull tools cause deflection and smearing rather than clean cuts. High surface speeds (300–500 SFM) with sharp carbide or HSS tooling produce the best finish. Avoid dwelling — it generates heat and causes gummy buildup.
-
2
Account for thermal expansion and stress relief
PP has a high coefficient of thermal expansion (~15 × 10⁻⁵/°C). Allow material to acclimate to shop temperature before machining. For tight-tolerance parts, roughing passes followed by a rest period before finishing reduces residual stress-induced distortion.
-
3
Hot gas welding is the preferred joining method
PP welds well with PP filler rod at 270–300°C using nitrogen or air. Butt welds achieve 80–90% of parent material strength. Solvent bonding does not work with PP — the lack of polarity makes it one of the harder plastics to adhesive bond. Surface treatment (corona, flame) is required before adhesive application.
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4
PP homopolymer can become brittle at low temperatures
Below -10°C, standard homopolymer notched impact resistance drops sharply. If machined parts will be handled in cold storage or shipped in winter climates, specify impact copolymer instead — it maintains acceptable toughness to around -20°C without a meaningful density change.
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5
Glass-filled PP requires different tooling considerations
PP 30% Glass-Filled is significantly more abrasive than unfilled grades. Carbide tooling is mandatory. Expect faster tool wear and shorter tool life. Dust generated during machining contains glass fibers — use appropriate respiratory protection and dust extraction.
Standards and Certifications
Standard Specification for Polypropylene Injection and Extrusion Materials. Covers material classification, property requirements, and test methods for all PP grades.
Olefin polymers permitted for food contact use. Applies to FDA Grade PP only. Covers indirect food additives — plastics used for food packaging and food processing equipment.
Food Equipment Materials. Applies to FDA Grade PP in food equipment construction. Required for commercial kitchen and food processing equipment in many jurisdictions.
RoHS Compliance
All PP grades listed are RoHS compliant. PP does not contain restricted heavy metals or halogenated flame retardants. Flame retardant PP grades would require separate compliance verification.
Density Test Methods
Density values on this page are per ISO 1183 / ASTM D-1505 (density gradient column method), verified against SABIC Polymer Product Catalogue. These are the appropriate methods for solid plastic density measurement.
Frequently Asked Questions
What is the density of polypropylene?
Polypropylene density depends on the grade. PP Homopolymer and PP Impact Copolymer are both 0.905 g/cm³. PP Random Copolymer is slightly lighter at 0.898 g/cm³ due to the comonomer structure. PP FDA Grade is 0.905 g/cm³ — identical to standard homopolymer mechanically. PP 30% Glass-Filled is significantly denser at 1.13 g/cm³ due to the glass fiber content. All unfilled grades are lighter than water (density below 1.00 g/cm³).
How do I calculate PP sheet weight?
For a PP sheet in millimeters: Weight (g) = Length × Width × Thickness (all in mm) ÷ 1000 × Density (g/cm³). For example, a 1000 mm × 500 mm × 6 mm sheet of PP Homopolymer at 0.905 g/cm³ calculates as: (1000 × 500 × 6) ÷ 1000 × 0.905 = 3,000 cm³ × 0.905 = 2,715 g (2.715 kg). For imperial dimensions, enter inches in this calculator with the imperial toggle selected and the formula handles the conversion.
How do I calculate PP rod weight?
For a PP rod in millimeters: Weight (g) = π × (Diameter ÷ 2)² × Length (mm) ÷ 1000 × Density (g/cm³). For a 1 inch (25.4 mm) diameter PP Homopolymer rod, 8 feet (2438.4 mm) long: π × 12.7² × 2438.4 ÷ 1000 × 0.905 = 1,240 cm³ × 0.905 = 1,122 g (1.12 kg).
What is the difference between PP homopolymer and PP copolymer?
PP Homopolymer is pure polypropylene — stiffest grade, best chemical resistance, highest service temperature, but brittle below -10°C. PP Random Copolymer adds a small amount of ethylene during polymerization, which disrupts crystallinity, reduces density slightly to 0.898 g/cm³, improves clarity, and significantly improves low-temperature impact resistance — at the cost of slightly lower stiffness and maximum service temperature (90°C vs 100°C). PP Impact Copolymer is a heterophasic structure — a homopolymer matrix with a dispersed rubber phase — giving the highest impact resistance of any unfilled PP grade, especially at cold temperatures, with the same density as homopolymer but lower stiffness.
Is PP lighter than HDPE?
Yes. PP Homopolymer (0.905 g/cm³) is about 6–7% lighter than typical HDPE (0.950–0.965 g/cm³) for the same volume. Both float in water. In practice, if you replaced a 10 kg HDPE part with PP, the PP equivalent would weigh approximately 9.3–9.4 kg — a meaningful difference in shipping cost and assembly ergonomics for large parts.
Is polypropylene FDA approved for food contact?
Only specifically designated FDA Grade PP is compliant for food contact under 21 CFR 177.1520. Standard homopolymer, random copolymer, and impact copolymer grades are not automatically FDA approved for food contact — compliance depends on the specific additives and colorants used by the resin supplier. If food contact compliance is required, always request the supplier's FDA letter of compliance and specify FDA Grade in your purchase order. NSF 51 (food equipment) applies to PP FDA Grade for commercial kitchen and food processing equipment applications.