What’s the Difference Between Bioplastic and Compostable Plastic?

The two terms get used interchangeably, which is a problem because they describe different things. A bioplastic is a plastic made from biological (renewable) feedstock — plants, agricultural byproducts, or sometimes bacterial fermentation. A compostable plastic is a plastic that breaks down to acceptable levels under defined composting conditions. Some plastics are both. Some plastics are one but not the other. Plenty of marketing language treats them as the same, which causes confusion at procurement, certification, and end-of-life stages.

This is a working untangling of the two terms — what each means, what the overlap looks like, common examples that confuse people, and why getting the distinction right matters in practice.

The two questions are different

When you encounter a plastic-like material, two separate questions apply:

Question 1: What is it made from? Is the feedstock petroleum (fossil-based) or biological (plant or microbial)?

Question 2: What happens at end of life? Does it break down in composting conditions, in industrial conditions only, in marine environments, or essentially never (conventional plastic durability)?

These are independent questions. The feedstock origin doesn’t determine the end-of-life behavior, and the end-of-life behavior doesn’t determine the feedstock.

A 2×2 matrix captures the combinations:

Every cell of this matrix has real-world examples. The relevant question for procurement and disposal isn’t which cell the material lives in but which two attributes you actually care about — and those depend on what you’re trying to accomplish.

What “bioplastic” actually covers

“Bioplastic” is an umbrella term that includes any plastic made from biological feedstock, regardless of end-of-life behavior. Common examples:

Bio-polyethylene (bio-PE). Polyethylene plastic made from sugarcane ethanol instead of petroleum. The finished plastic is chemically identical to conventional polyethylene — same recycling stream (#2 or #4 in the resin code system), same end-of-life behavior (essentially indefinite environmental persistence). Bio-PE doesn’t compost; it just has bio-based feedstock origin.

Bio-polyethylene terephthalate (bio-PET). Same logic applied to PET bottles. The Coca-Cola “Plant Bottle” was a notable commercial example — a bio-PET bottle that’s chemically PET (recyclable as #1) but made partly from plant-derived feedstock. Doesn’t compost; not biodegradable in environmental conditions.

Polylactic acid (PLA). The compostable bioplastic. Made from fermented plant sugars (corn, sugarcane, cassava), forms a clear plastic that’s used in cold cups, deli containers, and as the lining for compostable paper cups. Compostable in industrial facilities (not home compost). The most common bioplastic-and-compostable overlap.

Polyhydroxyalkanoate (PHA). Newer bioplastic family produced by bacterial fermentation of plant sugars or oils (and in some cases, methane). Compostable in a broader range of conditions than PLA — some PHA grades are home-compostable and marine-biodegradable.

Starch-based plastics (PSM, TPS). Plastics made primarily from starch with various plasticizers. Compostable in industrial conditions. Used for some bag and film applications.

Bio-polybutylene succinate (bio-PBS). Bioplastic that’s compostable in industrial conditions; used for some hot-cup linings.

Cellulose-based plastics. Made from wood pulp or cotton cellulose; includes cellophane and some bio-derived plastic alternatives. Often compostable.

Bio-nylon and bio-polyamide. Bio-based versions of nylon used in some textile applications. Not typically compostable.

The bioplastic category is diverse. Some bioplastics are compostable; many aren’t.

What “compostable plastic” actually covers

“Compostable plastic” is the subset of plastics that meet defined compostability standards (typically ASTM D6400, ASTM D6868, or EN 13432). Common examples:

PLA (mostly bio-based, compostable in industrial conditions). The largest-volume compostable plastic.

PHA (bio-based, compostable in industrial and often home conditions). Growing share of the compostable category.

Polybutylene adipate-co-terephthalate (PBAT). Importantly, PBAT is a compostable plastic that’s PETROLEUM-based, not bio-based. PBAT is often blended with PLA, starch, or other bioplastics to improve mechanical properties. So a “compostable” product can be partly petroleum-derived (the PBAT component) even though the overall product is industrial-compostable certified.

Compostable starch blends. Mixtures of starch with PBAT or other compostable polymers. Used for compostable bags, agricultural mulch films, and some packaging.

Compostable PBS and PBSA (polybutylene succinate, polybutylene succinate-adipate). Compostable in industrial conditions; used for some hot-application items.

Compostable cellulose-based films. Specific cellulose plastics certified to compostability standards.

The compostable category includes both bio-based and petroleum-based components. A common product (compostable bag, for example) is often a blend of PLA (bio-based) and PBAT (petroleum-based), with the resulting product certified compostable but with a feedstock origin that’s mixed.

The overlap and where it matters

The Venn diagram of these categories:

• Bioplastic only (not compostable): Bio-PE, bio-PET, bio-nylon, some bio-PUR
• Compostable only (not bio-based): PBAT alone (rare in finished products)
• Both bioplastic AND compostable: PLA, PHA, starch blends, bio-PBS, compostable cellulose
• Neither: Conventional PE, PP, PS, PET, PVC, conventional nylon

For procurement purposes, the relevant attribute depends on the goal:

If the goal is reduced fossil-fuel feedstock: Either category (bioplastic or compostable bio-based) helps, but bio-based is the key attribute. A bioplastic that doesn’t compost still reduces oil consumption at the feedstock stage.

If the goal is improved end-of-life behavior: Compostable is the key attribute. A bioplastic that doesn’t compost still goes to landfill or recycling like conventional plastic. Compostable plastics can divert to composting.

If the goal is both: Look for bio-based AND compostable products — PLA, PHA, certified bio-based compostable blends.

If the goal is reduced overall plastic use: Neither bioplastic nor compostable is the answer; the answer is reuse or material substitution (paper, fiber, glass, metal, real reusables).

Common confusion patterns

The interchangeable use of these terms creates several common confusion patterns:

Confusion 1: “It says bioplastic, so I can compost it.”
False. Bio-PE and bio-PET are bioplastics but don’t compost. Throwing them in a compost bin contaminates the compost stream. Verify the specific compostability claim, not just the feedstock claim.

Confusion 2: “It says compostable, so it’s all bio-based.”
False. Some compostable products contain significant PBAT or other petroleum-derived components. The product is still industrial-compostable certified, but the feedstock isn’t entirely bio-based.

Confusion 3: “Biodegradable and compostable are the same.”
Different. All plastics will biodegrade eventually given enough time. The relevant question for “compostable” is “biodegradable in defined composting conditions within a defined timeframe” (e.g., 90-180 days for ASTM D6400). Generic “biodegradable” claims without specific testing standards are often marketing without verification.

Confusion 4: “Plant-based means compostable.”
Often but not always. PLA and PHA are plant-based and compostable; bio-PE is plant-based but not compostable.

Confusion 5: “If it composts, it must be bio-based.”
Not always. PBAT is a compostable plastic that comes from petroleum. Some commercial compostable products use PBAT as a primary or significant component.

These confusions are widespread in consumer-facing language and even in some B2B marketing. The clarifying move is always to look at specific certifications and feedstock claims rather than relying on general terms.

Why feedstock origin matters

For procurement decisions and lifecycle analysis, the feedstock origin matters for several reasons:

Climate impact at production. Bio-based feedstocks generally have lower carbon footprint at production than petroleum feedstocks, because the plant material removed CO2 from the atmosphere during growth. The math gets complicated (depends on agricultural inputs, processing energy, land-use change, etc.) but the direction is favorable for bio-based.

Resource depletion considerations. Bio-based feedstocks are renewable (plants regrow); petroleum feedstocks are not. For materials in long-term scaled production, renewable feedstocks have advantages.

Supply chain resilience. Bio-based feedstocks have different supply chain risks than petroleum (weather, agricultural commodity prices, land-use conflicts) but offer alternative supply pathways that don’t depend on oil markets.

Certifications and labeling. Various certifications (USDA BioPreferred, EU Bioplastic certifications) specifically address feedstock origin, separately from end-of-life. Products targeting these certifications need verified bio-based content.

Why compostability matters

The end-of-life question is separately important:

Diversion from landfill. Compostable products can flow to composting (where infrastructure exists) instead of landfill. Reduces methane from landfilled organics; produces useful compost.

Marine and environmental behavior. Compostable products that meet marine biodegradability standards (TÜV OK Marine, ASTM D7081) have meaningfully different environmental fate if they escape into oceans or waterways.

Regulatory compliance. Some jurisdictions have banned non-compostable single-use plastics in certain categories. Compostable alternatives provide compliance pathway.

Customer perception. Consumer-facing brands often value the visible “compostable” claim because customers understand what it means.

A practical procurement framework

For buyers making category decisions, the framework that handles both attributes:

Step 1: Identify your priorities.
– Reduced feedstock impact? Focus on bio-based content.
– Improved end-of-life? Focus on compostable certifications.
– Both? Look for products that satisfy both criteria.

Step 2: Verify claims through certifications.
– Bio-based claims: USDA BioPreferred certification at specified percentages
– Compostable claims: BPI certification, TÜV OK Compost (with appropriate scope: industrial, home, marine), CMA approval

Step 3: Match to your end-of-life infrastructure.
– Industrial-compostable products need industrial composting access at scale
– Home-compostable products work in home composting contexts
– Marine-biodegradable products mainly matter for products with environmental escape risk

Step 4: Verify supplier transparency.
– Reputable suppliers will provide certification numbers and lifecycle data
– Suppliers who hedge on these specifics are signaling that claims may not be backed by verification

Common applications and their typical material choices

For specific common applications, the typical material choice:

Compostable cold cups: PLA (bio-based, industrial compostable). The clear cup material of choice.

Compostable hot cups: PLA-lined or PBS-lined paper. The lining can be PLA (bio-based, industrial compostable) or PBS (bio-based or partly bio-based, industrial compostable). The paper substrate is typically wood pulp.

Compostable straws: PLA (industrial compostable) or PHA (home compostable, marine biodegradable). PHA is gaining share because of its broader compostability.

Compostable cutlery: CPLA (PLA with mineral filler) or wood (renewable, home compostable).

Compostable bags: Typically PLA-PBAT blends, or PBAT-starch blends. Industrial compostable. Many are home-compostable certified.

Compostable food containers: Bagasse (fiber-molded, fully bio-based, industrial compostable) for hot food; PLA for cold or clear containers; PLA-lined paper for hot drinks.

For most of these, the products you’ll encounter in the market are both bio-based and compostable. The exceptions (PBAT-containing products that are compostable but partly petroleum-derived) are visible to procurement teams paying attention to feedstock details.

What about marine and home compostability

Compostability claims have different scopes:

Industrial compostable (ASTM D6400, TÜV OK Compost Industrial): Breaks down in commercial composting facilities at thermophilic temperatures (130-160°F) within 90-180 days.

Home compostable (TÜV OK Compost Home): Breaks down at home composting conditions (lower temperatures, longer timeframes) — typically 12 months for full breakdown.

Marine biodegradable (ASTM D7081, TÜV OK Marine): Breaks down in marine water conditions within defined timeframes.

Soil biodegradable (TÜV OK Soil): Breaks down in normal soil conditions over defined timeframes.

A product can be certified to one of these standards without being certified to others. The relevant certification depends on the actual disposal pathway.

For most foodservice products in 2025, industrial compostable is the primary certification, with home compostable as bonus for products targeting consumer home use, and marine biodegradable as bonus for products with potential environmental escape (cutlery used on beaches, etc.).

The certification verification process

For procurement professionals or curious consumers wanting to verify specific claims:

Bio-based claims: USDA BioPreferred maintains a database of certified products. Check usda.gov/biopreferred for verification.

Compostable claims: Each certifying body maintains a public database:
– BPI: bpiworld.org/certified-products
– TÜV: tuv-at.be or vincotte.com search
– CMA: compostmanufacturingalliance.com

Plug in the certification number from the product packaging and verify the specific product is listed. Be aware that:
– Certifications expire (typically 3-5 years); check for current status
– Slightly different SKUs from the same brand may have different certifications
– Logos used without underlying certifications happen; verify the numbers

The terminology in regulations

Different jurisdictions use these terms with different specific meanings:

EU regulations generally distinguish bio-based from biodegradable from compostable, with separate compliance pathways for each. EN 13432 is the EU compostability standard.

US FTC Green Guides discourage unqualified “biodegradable” claims and provide guidance for specific terms.

State-level US regulations vary. California has explicit compostability labeling requirements (only ASTM-certified products can be marketed as compostable in California).

Asia-Pacific regulations vary widely. Some jurisdictions (Japan, Australia) have well-developed standards; others rely on imported certifications.

For B2B operations selling across multiple jurisdictions, understanding which terms apply in which markets is part of regulatory due diligence.

The bottom line

Bioplastic and compostable plastic are different concepts. Bioplastic is about feedstock; compostable is about end-of-life. Some plastics are both; some are one but not the other; some are neither.

For procurement decisions, use the specific certifications rather than the general terms. Verify on certification body databases. Match the certification scope to your actual disposal infrastructure.

For end-of-life decisions, don’t treat all bioplastics as compostable — many aren’t. Don’t treat all compostable plastics as bio-based — many contain petroleum components. The specific product certification determines the correct disposal.

For consumer communication, use specific language. “Industrially compostable, certified BPI” is verifiable. “Eco-friendly bioplastic” is marketing without substance.

The clarity matters in proportion to the decisions being made. For one consumer buying a single cup, the difference between bioplastic and compostable matters less. For a corporate buyer making category decisions, a city setting waste regulations, or a brand making sustainability commitments, the difference matters substantially.

For compostable food containers and the broader category of foodware products, the dual question — is it bio-based and is it certifiably compostable — is the framework that supports informed procurement. Asking and answering both questions specifically separates verified-substance products from marketing-only products.

The terminology will probably remain confusing for years as the consumer-facing language struggles to keep up with the technical reality. For those of us who need to make procurement, regulatory, or operational decisions today, the working approach is to ask the two specific questions, look for the two specific certifications, and not be misled by the general terms used in marketing.

Verifying claims at the SKU level: ask suppliers for a current Biodegradable Products Institute (BPI) certificate or an OK Compost mark from TÜV Austria, and check that retail-facing copy meets the FTC Green Guides qualifier requirement on environmental claims.