Degradable plastic is an oil-based plastic containing a chemical additive that undergoes significant change in its chemical structure, causing large polymer molecules to break down into smaller molecules or particles.

Bio-degradable plastic is a degradable plastic which results from the action of naturally occurring microorganisms such as bacteria, fungi, and/or algae.

Heat, moisture, and UV exposure cause the degradation of a degradable product, whereas microorganisms degrade a biodegradable product. Degradable products tend to take much longer to break down into carbon dioxide, biomass, and water.

When degradable plastics break down into smaller molecules, eventually they will be small enough to be consumed by microorganisms and so biodegradation occurs.

To summarise, all degradable films will eventually biodegrade but at different speeds.