What do the recycling numbers on plastic mean?

The number inside the triangle is a resin identification code. It identifies the type of plastic the item is made from. It is not a promise that the item is recyclable, and that misunderstanding is extremely widespread, partly because the surrounding arrows resemble a recycling symbol.

There are seven codes. The first is the clear plastic used for drinks bottles. The second is the opaque plastic used for milk bottles and detergent containers. These two have established markets and are the most reliably recycled.

The third is a chlorinated plastic used in pipes and some packaging, rarely accepted in household collections. The fourth covers films and carrier bags, which jam sorting machinery and usually require separate collection points. The fifth is used for tubs, pots and bottle caps, and acceptance varies considerably by area. The sixth is polystyrene, rarely recycled and often banned outright from kerbside collection. The seventh is a catch-all for everything else, including multi-layer materials that cannot be separated.

The practical implication is that the code tells you what a thing is, while your local collection guidance tells you whether to put it in the bin. The two are different questions, and only the second determines the outcome.

Items combining materials are the common trap. A pot with a foil lid and a plastic sleeve may carry a code while being unrecyclable as assembled, unless separated into parts.

Some packaging now carries clearer recyclability labelling alongside the code, which is more useful, though the schemes are national rather than universal.