This sounds easy - because there are common descriptions such as "72 litre bin liner", or "240 litre garbage bag", etc. etc. But did you know that these "descriptions" of bin liners actually vary throughout Australia? For example, a "72 litre garbage bag" in Melbourne can be different to a "72 Litre bin liner" in Adelaide, Perth, Brisbane or Sydney! That's because the "litre" description came from the garbage bin manufacturers, who all had slightly different ways of doing things.
The best way is to know exactly what bin liner dimensions (length and width) you need. If you aren't sure, or if you have a custom sized garbage bin receptacle then you can use the following method to estimate the ideal size you need:
Packaging, Environment and Legislation Observations from Maxpak
Environmental Packaging, Plastic Bags, Paper Bags, Shopping Bags, Cleaning Wipes & Products, Garbage Bags & Liners, Packaging & Cleaning Products