Biodegradable vs. Compostable Packaging: An Australian Business Guide

Biodegradable means a material will eventually break down through natural biological processes, with no set timeframe, no defined conditions and no guarantee about what it leaves behind. Compostable means a material has been tested to break down within a specific period under defined composting conditions, leaving no toxic residue. In Australia, compostable claims are backed by two certification standards: AS 4736 for commercial composting facilities and AS 5810 for home composting. Biodegradable, on its own, is backed by nothing.

That distinction matters more for organisations than for households. When a Sydney business, school or council chooses packaging at institutional volume, the difference between a verified claim and a vague one flows through to waste contracts, sustainability reporting and compliance with tightening state regulations. This guide explains both terms properly, then works through the question that actually decides the purchase: which disposal pathway will this packaging really end up in?

What biodegradable actually means?

Almost everything biodegrades eventually, including materials that take decades and shed harmful fragments along the way. That is the core weakness of the word. Some products marketed as biodegradable are conventional petroleum plastics with additives that accelerate fragmentation. The plastic breaks into smaller and smaller pieces, and those pieces persist in soil and waterways as microplastics.

Genuinely biodegradable materials do exist, and they are usually the ones that were never plastic to begin with. Paper, kraft, cardboard, cellulose film and plant-fibre products break down through natural processes into organic matter because they are organic matter. Our existing guide to biodegradable packaging covers these materials in detail. The practical rule for procurement teams: a biodegradable claim is only meaningful when the material itself is plant-based and the supplier can say what it is made from.

What compostable actually means?

Compostable is the stricter, verified claim. Under AS 4736, a product must substantially convert to carbon dioxide, water and biomass within 180 days in a commercial composting facility, disintegrate to fine particles within 12 weeks, and leave no toxic residue in the finished compost. Under AS 5810, the product must achieve the same outcome in the cooler, less controlled conditions of a home compost system. The Australasian Bioplastics Association administers certification in Australia, and certified products carry the relevant logo.

The certification distinction has a practical edge. An AS 4736 certified product needs a commercial composting facility to break down as tested. If your organisation’s waste contractor does not collect organics, that certified compostable item goes to landfill, where the cold, oxygen-starved conditions prevent it from composting at all.

The comparison at a glance

The disposal pathway decides everything

Here is the question that should sit above both terms on any procurement checklist: where will this packaging actually go after use?