What materials are used to make a car body

Most modern car bodies are primarily made from advanced steels and aluminum, complemented by plastics for bumpers and trim, glass for windows, and composites in select panels or high-performance models; electric vehicles increasingly add large aluminum castings and specialized battery enclosures. In practice, automakers use a multi-material mix to balance safety, weight, cost, manufacturability, and repairability.

The core materials in a modern car body

Car bodies combine several material families, each chosen for specific properties such as strength, formability, corrosion resistance, and cost. The list below outlines the main materials you’ll find and what they contribute.

• Steels: Mild steel, high-strength low-alloy (HSLA), advanced high-strength steels (AHSS), ultra-high-strength steels (UHSS), and press-hardened boron steels (e.g., 22MnB5). These form most “body-in-white” structures thanks to excellent crash performance and cost-effectiveness.
• Aluminum alloys: Primarily 5xxx (sheet) and 6xxx (sheet, extrusions), plus large structural castings in some EVs and premium models. Used for hoods, doors, roofs, fenders, tailgates, and structural members to cut weight.
• Plastics and polymer composites: Thermoplastics such as polypropylene (PP), ABS, and polycarbonate (PC), and thermoset composites like sheet molding compound (SMC) or long-fiber-reinforced plastics for exterior panels, bumper fascias, and liftgates.
• Carbon fiber–reinforced polymer (CFRP): Lightweight, very strong composite used in sports cars and select structural or body panels where cost allows.
• Magnesium alloys: Very light die-cast parts used sparingly (e.g., specific reinforcements or inner frames), less common on outer body due to corrosion and cost constraints.
• Glass: Laminated safety glass (windshield) and tempered safety glass (side and rear windows). Some niche use of polycarbonate glazing exists but is limited by regulations and scratch resistance.
• Rubber, foams, and sealants: Weatherstrips, NVH (noise, vibration, harshness) foams, and seam sealers that keep out water, reduce noise, and improve comfort.
• Structural adhesives and tapes: Epoxy and polyurethane systems that boost stiffness, improve crash energy flow, and enable joining dissimilar materials.
• Corrosion protection and coatings: Zinc coatings (galvanized/galvannealed steel), e-coat primers, primers, basecoats, and clearcoats that protect and finish the body.

Together, these materials create a body that meets crash standards, resists corrosion, looks good, and can be built at scale—while staying as light and affordable as possible.

Where each material is used on the car body

Automakers deploy materials strategically across the vehicle to optimize safety, strength, styling, and weight. The following overview maps common materials to specific body areas.

1. Body-in-white (BIW) structure: Predominantly AHSS/UHSS with tailored blanks and press-hardened steel in pillars, rockers, sills, and crash rails; aluminum may appear in front and rear substructures, shock towers, and crossmembers, especially on lighter platforms.
2. Closures and outer panels: Aluminum sheets on hoods, trunks, doors, roofs, and fenders in many mid/high-end and EV models; steel remains common in mass-market vehicles; SMC/plastic used for decklids and liftgates on some models.
3. Bumpers and fascias: Thermoplastic fascias over steel or aluminum crash beams; energy absorbers made from foams or engineered plastics.
4. Glazing: Laminated windshield and tempered side/rear windows; acoustic laminated side glass on premium models; limited polycarbonate in non-regulated or motorsport applications.
5. Underbody and battery enclosures (EVs): Extruded and stamped aluminum, steel, or composite housings with fire-resistant layers; underbody shields often plastic or fiber-reinforced composites.
6. Castings and nodes: Increasingly large aluminum castings (“giga-castings”) for front/rear underbodies in some EVs and premium cars; smaller cast nodes used to simplify assemblies.

This mix lets engineers reinforce critical crash paths, reduce mass where it matters most, and streamline manufacturing without compromising safety or quality.

Why manufacturers mix materials

No single material best solves every requirement. The combination is driven by physics, regulations, and economics. These factors explain most choices.

• Crash safety: AHSS/UHSS and press-hardened steels provide exceptional energy absorption and occupant protection; aluminum and composites can be tuned for controlled deformation.
• Weight reduction: Aluminum, magnesium, and composites cut mass to improve fuel economy and EV range without sacrificing stiffness.
• Cost and scalability: Steel is inexpensive and well-understood; aluminum and composites cost more but can reduce part counts or enable new designs.
• Manufacturability and joining: Steels spot-weld easily; mixed-material designs use adhesives, rivets, and screws; composites require different curing and bonding methods.
• Corrosion and durability: Zinc-coated steels and aluminum resist corrosion; sealers and coatings extend life, especially in harsh climates.
• NVH and ride quality: Foams, adhesives, and mass-damping materials quiet the cabin and increase perceived quality.
• Repairability and insurance: Aluminum and composites need specialized repair techniques; mixed bodies can raise repair costs but may lower operating costs via weight savings.

The end result is a targeted blend that meets safety rules, achieves design goals, and fits the vehicle’s price point and brand positioning.

How parts are joined and protected

The effectiveness of a multi-material body depends on joining and corrosion protection. These technologies keep the structure strong over its lifetime.

• Joining technologies: Resistance spot welding (steel), laser welding, MIG/TIG (aluminum), self-piercing rivets (SPR), flow-drill screws (FDS), hemming for closures, clinching, and extensive structural adhesives for stiffness and mixed materials.
• Corrosion protection: Hot-dip galvanized/galvannealed steel, e-coat immersion primer, seam sealers, cavity waxes, primers/basecoats/clearcoats; aluminum passivation and advanced pretreatments.
• Thermal and fire protection (EVs): Insulative foams, ceramic or mica layers, and intumescent coatings around battery enclosures to mitigate thermal events.

These methods ensure the car body resists rust, maintains structural integrity, and performs consistently in real-world conditions.

Trends to watch in 2025

Materials are evolving rapidly as EV adoption and efficiency targets reshape vehicle architectures. These developments are increasingly visible on new models.

• Large aluminum castings: Front and rear “megacast” structures simplify assemblies, shift mass distribution, and can reduce part counts.
• More AHSS and press-hardened steels: Third-generation AHSS expands the strength–ductility window, enabling thinner gauges without losing crash performance.
• Battery enclosures: Growth of aluminum extrusions and stamped steel boxes, plus composite lids and fire-resistant layers to manage thermal risk and weight.
• Sustainability: Higher recycled content in steel and aluminum, recycled polymers for fascias/liners, and bio-based binders in select composites.
• Lightweight glazing: Wider use of acoustic laminated side glass and thinner, stronger laminates; polycarbonate remains niche due to durability rules.
• Advanced coatings: More waterborne paints, lower-VOC chemistries, and improved e-coat processes for better corrosion protection with reduced environmental impact.

Expect continued convergence on multi-material strategies tailored to platform, price segment, and regional regulations.

Typical material breakdown by mass

Exact shares vary by model and segment, but the following ranges are typical for today’s passenger vehicles and reflect the body’s contribution within the whole vehicle mass.

• Steel (including AHSS/UHSS/PHS): Often the largest share of the body-in-white; mainstream vehicles commonly allocate a majority of structural mass to steel.
• Aluminum: From modest use in mainstream models to extensive use (closures and structures) in premium/EVs; large castings can shift more mass to aluminum.
• Plastics/composites: Significant in exterior fascias, underbody shields, wheel arch liners, and some panels; typically a smaller fraction of total vehicle mass but visually prominent.
• Glass: A small share of overall mass, dominated by the windshield and panoramic roofs where fitted.
• Magnesium and CFRP: Niche in most volume cars; higher in performance or luxury segments where cost allows.

Because material choices are platform-specific, two similarly sized cars can differ notably in body mass and composition, even within the same class.

Buying and repair implications

Material choices influence ownership costs and repair outcomes. Shoppers and owners may notice these effects over a vehicle’s life.

• Repair complexity: Aluminum and composite panels often require specialized tools and training, affecting repair times and costs.
• Corrosion resistance: Galvanized steel and aluminum bodies generally resist rust well when coatings are intact; prompt chip/paint repairs help longevity.
• Insurance and safety ratings: Multi-material structures can improve crash performance and may influence insurance groupings; repairability can also impact premiums.
• Efficiency and range: Lighter closures and structures can improve fuel economy and EV range, especially in city driving.

Understanding the car’s material makeup can help set expectations for durability, costs, and performance over time.

Summary

Car bodies today are engineered from a mix of advanced steels, aluminum alloys, plastics/composites, safety glass, and specialized adhesives and coatings. Steels dominate many structural areas for crash safety and cost, while aluminum and composites reduce weight in closures and selective structures. EVs add large aluminum castings and sophisticated battery enclosures. This multi-material strategy lets automakers meet safety, efficiency, durability, and styling goals across price points and segments.

What were the bodies of cars in 2025 made of?

The study finds that every leading automaker will have numerous aluminum body and closure programs by 2025. As the material mix for body and closure parts continues to change in the years to come, use of aluminum sheet for vehicle bodies will increase to 4 billion pounds by 2025, from 200 million pounds in 2012.

What materials are car bodies made of?

Car bodies are made from a combination of materials, primarily steel, aluminum, and plastics, along with glass and rubber for other components. Steel remains a staple for its durability and cost-effectiveness, while aluminum offers a lighter, fuel-efficient alternative. Plastics are widely used for everything from dashboards to body panels, and high-performance vehicles sometimes incorporate expensive materials like carbon fiber for extreme lightness and strength.
 
Key Materials

• Steel: Opens in new tabThe most traditional and common material, steel is strong, durable, and inexpensive. Modern steel can be engineered to crumple in a controlled way to absorb impact, and it is often coated in zinc (galvanized) to prevent rust. 
• Aluminum: Opens in new tabA lighter alternative to steel, aluminum helps reduce a car’s overall weight, improving fuel efficiency. It’s a popular choice for both common vehicles and high-performance cars, with increasing use in hybrid and electric vehicles. 
• Plastic: Opens in new tabUsed in various forms, plastics are prevalent in cars today, making up a significant portion of a vehicle’s construction. They are used for interior components like dashboards and switches, but also for some body panels. 
• Carbon Fiber: Opens in new tabA lightweight and incredibly strong composite material, carbon fiber is the pinnacle of performance materials but is very costly. It is reserved for high-end sports cars and specialized racing applications, though some modern production cars use it for key structural components. 
• Glass: Opens in new tabUsed for windows and windshields. 
• Rubber: Opens in new tabFound in components like tires, but also used in other parts of the car’s body. 

Why the Mix of Materials?
The automotive industry balances several factors when choosing materials for car bodies: 

• Cost: Steel remains the cheapest option, while high-performance materials like carbon fiber are significantly more expensive. 
• Weight: Lighter materials like aluminum and carbon fiber improve fuel efficiency and performance. 
• Strength and Safety: Materials are selected and engineered to provide a strong safety cage for occupants and to absorb crash energy in predictable ways. 
• Fuel Efficiency: Reducing vehicle weight with lighter materials directly impacts fuel consumption. 
• Environmental Impact: The recyclability of materials like steel also plays a role. 

What is the most common vehicle construction material?

Steel (Iron Ore)
Steel is produced from iron ore and is traditionally widely used in auto manufacturing. On average, 900 kilograms of steel are used in every car. Steel is used to construct a car’s chassis and body, including the roof, body, door panels, and the beams between doors.

Why are car bodies not made of plastic?

There are a few reasons why cars don’t have more plastic body panels. The first is that plastic is not as strong as metal, so it can’t be used in areas that need to be strong, like the frame of the car. Additionally, plastic is more expensive to produce than metal, so it would be more expensive for the consumer.