What Is the Most Common Car Material?

Steel—especially high‑strength and advanced high‑strength steels—is the most common material used in cars today, typically making up about 50–60% of a mainstream vehicle’s weight. While aluminum, plastics, and composites are increasingly important, steel remains dominant in body structures and many chassis parts because it balances strength, safety, manufacturability, cost, and recyclability.

Why Steel Still Leads

Modern automakers rely on steels that are far stronger and lighter than traditional grades. Advanced high‑strength steel (AHSS) enables thinner sections without sacrificing crash performance, helping carmakers meet safety rules and emissions or efficiency targets at a competitive cost. Steel is also easy to stamp, weld, and integrate at scale—key advantages for high‑volume production.

What “Most Common” Means in Practice

Material dominance can be measured in several ways: by share of vehicle mass, by number of parts, or by value. In mass terms—the most common yardstick—steel is the clear leader across global vehicle production. In certain premium or electric vehicles, aluminum’s share rises substantially, and interior volumes are largely plastics by space, but steel remains the primary material by weight across the industry.

Typical Material Mix in Modern Vehicles

The following ranges reflect broad industry averages for light vehicles; figures vary by region, segment, and whether the vehicle is an internal-combustion model or an EV.

• Steel (conventional, high‑strength, and AHSS): roughly 50–60% of total vehicle mass
• Aluminum: about 10–15% on average; up to 25–35% in some aluminum‑intensive or EV platforms
• Plastics and polymer composites: approximately 8–12% by mass (much higher by volume in interiors)
• Cast iron: around 3–10%, mainly in traditional engine blocks and brake components; declining as powertrains evolve
• Rubber and elastomers: roughly 4–6%
• Glass: about 2–3%
• Copper: typically 1–2% in ICE vehicles; around 2–4% in EVs due to motors and cabling
• Magnesium: generally under 1%, used selectively for lightweight castings
• Carbon fiber and other advanced composites: usually well under 1% outside high‑end or performance models

These proportions illustrate why steel is widely regarded as the automotive baseline: even as other materials grow in targeted applications, steel remains the backbone of most mass‑market vehicles.

Where Different Materials Are Used

Automakers deploy materials where their properties deliver the most benefit for safety, performance, manufacturing, and cost.

• Body‑in‑white (BIW) and crash structure: high‑strength and advanced high‑strength steels dominate for energy absorption and rigidity
• Closures and exterior panels: mixed—steel for cost and dent resistance; aluminum for weight savings on hoods, doors, and tailgates
• Chassis and suspension: steel for control arms, subframes, springs; aluminum used selectively to trim mass and improve dynamics
• Powertrain: historically cast iron for blocks and rotors; growing use of aluminum for engine/transmission housings; EV motors and inverters add copper and specialized steels
• Battery systems (EVs): aluminum or steel enclosures; internal modules and cooling plates often aluminum; structural floors increasingly mixed‑material
• Interior: plastics, foams, fabrics, and composites for panels, seats, and trim, optimizing weight, cost, and design flexibility
• Wheels and brakes: steel and aluminum wheels; iron or steel brake components, with composites emerging at the high end

The result is a multi‑material “right‑material, right‑place” strategy, with steel anchoring the structure and other materials deployed to meet specific performance goals.

EVs and the Material Shift

Electric vehicles push the mix toward lightweight metals in some areas—aluminum for large castings, battery enclosures, and body panels—to offset battery mass and extend range. Even so, many EV body structures remain predominantly steel, leveraging new AHSS grades that exceed 1,200–2,000 MPa tensile strength. The industry trend is toward optimized multi‑material architectures rather than a single “all‑aluminum” or “all‑composite” future for mainstream models.

Sustainability and Recycling

Steel and aluminum both have mature recycling streams—critical for lowering lifecycle emissions. Vehicles are among the world’s most recycled products by mass, with steel achieving high recovery rates and aluminum often reclaimed in closed‑loop manufacturing. As low‑carbon steel (including electric‑arc and hydrogen‑reduced pathways) and greener aluminum smelting scale up, the embedded carbon of vehicle materials is expected to decline, reinforcing their continued use.

What Decides the Material Choice

Engineers weigh multiple constraints before specifying a metal, polymer, or composite for any component.

• Crash safety and stiffness targets
• Weight and efficiency/range requirements
• Manufacturing processes, cycle times, and repairability
• Cost, supply chain resilience, and global availability
• Corrosion resistance and durability
• Recyclability and lifecycle carbon footprint
• Design freedom, packaging, and NVH (noise, vibration, harshness) goals

Because steel often offers the best overall balance of these factors—especially at scale—it remains the default choice for much of a vehicle’s structure.

Outlook

Expect continued growth in high‑strength steels, strategic aluminum use, and targeted composites, particularly in EV platforms. Nonetheless, for the foreseeable future, steel will remain the most common car material globally by mass.

Summary

Steel is the most common car material, typically comprising about 50–60% of a modern vehicle’s weight. Its dominance reflects a practical balance of safety, strength, cost, manufacturability, and recyclability. While aluminum, plastics, and composites are expanding in targeted roles—especially in EVs—automakers are coalescing around multi‑material designs with steel at the core.

What is the most common material used in cars?

The main materials used for making cars, parts and components, along with future trends, are steel, aluminum, magnesium, copper, plastics and carbon fibers. The prime reason for using steel in the body structure is its inherent capability to absorb impact energy in a crash situation.

Are most cars steel or aluminum?

The most commonly used materials in your car are steel, plastic, aluminum, rubber, and glass. Steel is one of the heaviest and most widely used materials, making up a sizable percentage of the vehicle’s mass. Plastic is the most common material, used in various parts ranging from air bags to switches.

Are most cars made of fiberglass?

Are cars made of fiberglass? Yes. More and more car manufacturers are now using fiberglass in the design of their cars. Fiberglass is mainly used to construct the body of the car because it is lightweight and sturdy.

What material are most car bodies made of?

Car bodies today are most commonly made of steel and aluminum, with steel remaining a cost-effective choice for mass-produced vehicles. Aluminum is increasingly used for its lightweight properties, which improve fuel efficiency, particularly in larger vehicles. For higher-performance or more expensive sports cars, bodies can be made from strong but costly carbon fiber. Additionally, lightweight magnesium alloys are used for specific components, and various types of plastic are used for other parts like front and rear panels. 
Key materials and their uses:

• Steel: Opens in new tabRemains the traditional and most widely used material due to its strength, durability, and low cost. 
• Aluminum: Opens in new tabBecoming the material of choice for its lighter weight and corrosion resistance, used in components like hoods and liftgates. 
• Carbon Fiber: Opens in new tabA very strong and lightweight material, but its high cost restricts its use to high-end or specialty vehicles. 
• Plastic: Opens in new tabUsed extensively for various parts, including front and rear panels and other trims. 
• Magnesium Alloys: Opens in new tabLightweight magnesium is increasingly used for certain body components. 

Why the different materials are chosen:

• Cost: Steel is the most economical choice for most vehicles. 
• Weight: Aluminum and carbon fiber help reduce vehicle weight, leading to better fuel efficiency and performance. 
• Strength and Safety: All materials are chosen to meet strict safety standards, with different steels and other materials providing varying levels of crash protection. 
• Corrosion Resistance: Aluminum and certain steel treatments are important for protecting against rust.