Compostable vs Biodegradable: What's the Real Difference for B2B Buyers?

If you source packaging for a retail brand, distribution business, or e-commerce operation, you have almost certainly encountered the terms "compostable" and "biodegradable" in supplier catalogs, marketing materials, and certification documents. On the surface, both terms suggest that a material will "break down naturally" — which sounds like a positive environmental outcome regardless of the specific wording.

However, in the world of packaging regulation, certification testing, and consumer protection law, "compostable" and "biodegradable" are not interchangeable. The difference between them determines which claims you can legally make, which certifications your products need, and how your end customers should dispose of the packaging. Understanding this distinction is essential for any B2B buyer who wants to avoid greenwashing accusations, regulatory penalties, or supply chain mismatches.

What Does "Biodegradable" Actually Mean?

"Biodegradable" simply means that a material can be broken down by microorganisms — bacteria, fungi, and other biological agents — into smaller molecular components over time. The key point here is that the term does not specify:

• How long the breakdown takes

• Under what conditions (temperature, moisture, microbial environment)

• What the end products are (some biodegradable materials leave behind microplastics or toxic residues)

This lack of specificity is precisely why "biodegradable" has become a problematic label in many markets. A conventional plastic bag with an oxo-degradable additive might technically be "biodegradable" — but it could take years to fragment, and the resulting microplastics persist in the environment indefinitely.

For B2B buyers, this means that a "biodegradable" claim without supporting timeframes and conditions is essentially unenforceable. Some jurisdictions, including the European Union and several U.S. states, have restricted or banned the use of "biodegradable" claims on packaging precisely because the term is so vague.

What Does "Compostable" Mean — and Why Is It More Specific?

"Compostable" is a subset of biodegradability — but one that comes with precise, testable, and legally defined requirements. A material classified as compostable must:

1. Break down within a defined timeframe — typically 90–180 days in industrial composting conditions, or up to 6–12 months in home composting

2. Disintegrate completely — no visible fragments remain after the composting cycle

3. Convert into harmless substances — specifically CO₂, water, and organic biomass (humus)

4. Leave no toxic residue — the resulting compost must pass ecotoxicity tests and heavy metal limits

5. Pass specific standardized tests — such as EN 13432 (Europe), ASTM D6400 (USA), or AS 4736/AS 5810 (Australia)

These requirements are verified through third-party laboratory testing and certified by recognized bodies such as TÜV Austria (OK Compost), BPI (Biodegradable Products Institute), and DIN CERTCO. A certified compostable product carries a specific certification mark that buyers, regulators, and consumers can independently verify.

The Certification Landscape: Which Standards Matter Where?

For B2B buyers sourcing compostable packaging from international suppliers, understanding which certification applies to your target market is critical:

• EN 13432 — European standard for industrial compostability. Required for packaging sold into EU member states. Tests disintegration, biodegradation, ecotoxicity, and heavy metal content.

• ASTM D6400 — U.S. standard for compostable plastics in municipal and industrial facilities. The basis for BPI certification in North America.

• BPI Certification — Administered by the Biodegradable Products Institute, this is the primary U.S. compostability certification mark, built on ASTM D6400 testing.

• AS 4736 / AS 5810 — Australian standards for industrial and home compostability respectively. Increasingly referenced in procurement specifications from Australian government and corporate buyers.

• OK Compost HOME — TÜV Austria certification for products that compost under home conditions (lower temperatures than industrial facilities). Important for markets where home composting is the primary disposal route.

What This Means for Your Procurement Decisions

When evaluating packaging suppliers, the question should never be simply "is this biodegradable?" Instead, ask:

• Under what conditions does this product decompose? (Industrial composting, home composting, or unspecified?)

• What is the certified decomposition timeframe? (90 days? 180 days? Undefined?)

• Which third-party certifications does the product hold? (And are those certifications current and valid?)

• What disposal infrastructure exists in my target market? (If most consumers only have access to landfill, compostable claims may be misleading regardless of certification.)

The difference between compostable and biodegradable is not academic — it directly affects your labeling compliance, your brand's environmental claims, and your ability to serve markets with strict packaging regulations. B2B buyers who understand this distinction will source more confidently, communicate more transparently with end consumers, and build supply chains that withstand regulatory scrutiny.

At Halmfeld, our compostable product lines carry full EN 13432, ASTM D6400/BPI, and AS 4736/AS 5810 certifications. We provide complete certification documentation with every order so your compliance and marketing teams have the evidence they need.