“Biodegradable” and “compostable” get used as if they’re the same word. They’re not, and the gap between them changes what a product is legally allowed to claim, and whether your sustainability positioning actually holds up.
“Biodegradable” and “compostable” get used as if they’re the same word. On packaging, in supplier pitches, in casual conversation, they’re swapped in and out constantly, and most of the time nobody stops to ask whether they actually mean the same thing. They don’t, and the gap between them is wide enough that it changes what a product is legally allowed to claim, what happens to it after disposal, and whether a buyer’s sustainability positioning actually holds up.
This is a direct explanation of the real difference: what each term technically means, why one is a testable, certifiable claim and the other largely isn’t, and what that difference should change about how you source and market packaging.
The Problem: Two Words Treated as Synonyms, With Very Different Substance Behind Them
Ask most people to explain the difference between biodegradable and compostable, and you’ll get some version of “they’re basically the same thing, both mean it breaks down naturally.” That’s not wrong in spirit, both terms describe materials that break down through biological processes, but it glosses over a distinction that actually matters a great deal in practice.
“Biodegradable” is a broad, largely unregulated description. “Compostable” is a specific, testable claim tied to defined standards, timeframes, and thresholds. Buyers who don’t understand this difference end up unable to tell a corner-cut product from a genuinely tested one.
“Biodegradable” is a broad, largely unregulated description; “compostable” is a specific, certifiable claim with defined timeframes and thresholds.
Why It Matters: The Difference Changes What You Can Legally and Credibly Claim
- Only certified compostable products get specific regulatory exemptions in India. Several single-use plastic items are banned outright, with an exemption specifically for products certified compostable under IS/ISO 17088. A product simply marketed as “biodegradable,” without that certification, doesn’t qualify.
- “Biodegradable” carries almost no enforceable definition. It isn’t tied to a specific timeframe, testing method, or defined outcome in most contexts, so the word can be applied to products with wildly different real-world behaviour.
- Customers and auditors increasingly know the difference, or are learning fast. A brand using “biodegradable” as a stand-in for “compostable” risks being caught making a weaker claim than intended.
- The environmental outcomes are genuinely different. A certified compostable product is tested to confirm it breaks down into non-toxic compost within a defined timeframe. A biodegradable product, without that certification, might break down over decades, sometimes into microplastic fragments.
What “Biodegradable” Actually Means
Biodegradable, in its most basic and technically accurate sense, means a material can be broken down by living organisms — bacteria, fungi, or other microbes — into simpler substances over some period of time. That’s the entire technical content of the word. It says nothing about how long the process takes, what conditions are required, or whether any byproducts are harmful.
This is precisely why “biodegradable” is such an easy claim to make. Almost everything is biodegradable given enough time, including many conventional plastics, which do eventually break down, over decades or centuries, often fragmenting into microplastics along the way rather than fully biodegrading into harmless byproducts.
What “Compostable” Actually Means
Compostable is a narrower, specifically defined subset of biodegradable. A compostable material doesn’t just break down eventually, it breaks down within a defined timeframe, under specific composting conditions, into compost that isn’t toxic to plant life and doesn’t leave behind harmful residue.
In India, this is formally defined and tested under IS/ISO 17088, which requires a material to pass four separate parameters: disintegration into small fragments within roughly 12 weeks, at least 90% biodegradation within 180 days, no toxic effect on plant growth in the resulting compost, and heavy metal content below defined safety limits. A product only earns the compostable claim, and the certification that goes with it, by passing all four.
Side-by-Side: What Each Claim Actually Guarantees
| Biodegradable | Compostable | |
|---|---|---|
| Timeframe | Undefined, could be months to centuries | Defined: disintegration within ~12 weeks, biodegradation within 180 days |
| Testing standard | Generally none required to use the word | IS/ISO 17088 (India) or equivalent international standards |
| Toxicity check | Not required | Required: resulting compost tested for plant growth impact |
| Conditions specified | Usually unspecified | Specific composting conditions (typically industrial) |
| Certification available | No standard certification for the word alone | Yes, tied to specific product and manufacturer |
| Legal significance in India | Limited; doesn’t grant single-use plastic ban exemptions | Grants exemption for certified products under the SUP ban |
| Risk of misuse | High, word is easy to apply loosely | Lower, since certification requires third-party testing |
Why Every Compostable Product Is Biodegradable, But Not Every Biodegradable Product Is Compostable
This relationship is worth stating plainly because it clears up a lot of the confusion. Compostable is a stricter, more specific category nested inside the broader biodegradable category. A genuinely certified compostable product is, by definition, also biodegradable. But a product described as biodegradable has met none of the specific timeframe, toxicity, or process requirements that compostable certification demands, so it can’t be assumed to share the same environmental profile.
This is similar to how “square” and “rectangle” relate: every square is a rectangle, but not every rectangle is a square. Every certified compostable product is biodegradable, but calling something biodegradable tells you almost nothing about whether it meets the compostable bar.
Related Terms Worth Knowing
- Bio-based describes a material’s origin, made from plant or biological sources rather than petroleum, and says nothing about how it behaves at end-of-life. A bio-based plastic can be non-biodegradable and non-compostable.
- Degradable is an even weaker term than biodegradable in practice, sometimes describing materials that simply break apart physically over time, through UV exposure or mechanical stress, without any confirmed biological breakdown process.
- Oxo-degradable (or oxo-biodegradable) refers to conventional plastic with an additive that accelerates fragmentation under heat, light, or oxygen exposure. It is not compostable, and often results in smaller plastic fragments contributing to microplastic pollution. This category is specifically restricted under India’s Plastic Waste Management Rules.
- Home compostable is a distinct, generally stricter certification than standard (industrial) compostable, and shouldn’t be assumed from a standard compostable claim.
Where This Confusion Gets Weaponised in Marketing
The gap between these two words creates a specific, common marketing shortcut worth naming directly. A product that couldn’t pass, or was never tested against, compostable certification standards gets marketed as “biodegradable” instead — a claim that sounds similarly reassuring to a customer but requires no equivalent proof. This isn’t always deliberate deception; sometimes a supplier genuinely doesn’t understand the distinction either, but the effect on a buyer is the same either way.
This is worth watching for specifically with oxo-degradable plastics, which are sometimes marketed as “biodegradable” despite not being compostable, and in India, being specifically restricted under the Plastic Waste Management Rules precisely because of this kind of misleading positioning.
Examples: Where This Distinction Changes a Real Decision
- The single-use ban exemption miss — a restaurant switches its disposable cutlery to a supplier’s “biodegradable” range, assuming this satisfies the exemption for compostable products. The product was never IS 17088 certified, and the restaurant is still technically non-compliant.
- The marketing claim that couldn’t survive scrutiny — a D2C brand markets its packaging as “biodegradable and eco-friendly” without further specification. A sustainability-focused customer finds no certification behind it and points this out publicly.
- The correctly distinguished claim — a courier bag brand specifies precisely: “certified compostable under IS 17088, not merely biodegradable.” A procurement buyer recognises the specificity as a positive signal and moves the brand to the top of their shortlist.
A Buyer’s Checklist for Telling the Two Apart
- Treat “biodegradable” alone as an unverified claim until proven otherwise, since it typically requires no testing or certification.
- Ask specifically whether a product is certified compostable under IS/ISO 17088, not just described as biodegradable, if you need the single-use plastic ban exemption.
- Request the certification and test report for any compostable claim, following the same verification process that applies to any compostable packaging purchase.
- Be specific in your own customer-facing language: “certified compostable” is a stronger, more defensible claim than “biodegradable” alone.
- Watch for oxo-degradable products marketed loosely as “biodegradable,” since these are a specifically restricted category in India, not a genuine sustainability solution.
- When a supplier uses both words interchangeably in the same conversation, take that as a signal to ask more specific follow-up questions, not as reassurance.