What Do the Numbers on Plastic Recycling Symbols Mean?

Quick answer

The number inside the triangle of arrows on plastic is a resin identification code. It tells you which type of plastic the item is made from, from 1 for PET to 6 for polystyrene and 7 for other plastics. It does not tell you whether your local programme will accept the item for recycling.

What the code is and is not

The resin identification system was created so that sorting facilities and manufacturers could tell plastics apart, because different plastics melt at different temperatures and cannot simply be mixed. It is now maintained by ASTM International. The symbol looks like the universal recycling arrows, which is why it is so often read as a promise of recyclability.

It is better read as a label of ingredients. The same number printed on two packages means the same resin, but one may be accepted by your local collection and the other not, depending on its shape, size, colour, contamination and the equipment at the nearest sorting plant.

The seven codes

Resin identification codes and common uses
Code	Resin	Common examples
1	PET or PETE (polyethylene terephthalate)	Soft drink and water bottles, some food jars
2	HDPE (high-density polyethylene)	Milk jugs, detergent bottles, some bags
3	PVC (polyvinyl chloride)	Pipes, some clear packaging, cling film in some regions
4	LDPE (low-density polyethylene)	Shopping bags, squeeze bottles, film wraps
5	PP (polypropylene)	Yoghurt tubs, bottle caps, food containers
6	PS (polystyrene)	Foam cups and takeaway trays, disposable cutlery
7	Other, including blends and bioplastics	Some reusable bottles, mixed-material packaging

Number 7 is a catch-all. It covers several different plastics, so it gives the least information, and items marked 7 are the least likely to be accepted in ordinary collections.

Why a number is not a recycling instruction

Whether a plastic is recycled depends on markets, machinery and local rules, not on the code. EPA's material-specific data for the United States shows the gap. In 2018, plastics made up 35.7 million tons, or 12.2% of municipal solid waste generated, but only about 3 million tons, an 8.7% rate, was recycled. Of the plastics burned for energy, EPA reports 5.6 million tons, and 27 million tons went to landfill.

The recycling rates for the best-known containers were higher but still modest: 29.1% for PET bottles and jars and 29.3% for natural HDPE bottles. EPA describes the overall amount of recycled plastic as relatively small. In practice, PET (1) and HDPE (2) bottles are the plastics most widely collected, which is why many programmes name bottles and jugs rather than listing numbers.

Reading a plastic item's recycling status
Question	The code can tell you	Only your local programme can tell you
Which resin is it made of?	Yes, the number identifies the plastic	Not needed
Will my kerbside collection accept it?	No	Yes, check its accepted-items list
Does it contain recycled material?	No	Check the packaging for a separate recycled-content claim

How to recycle plastics more effectively

Check your local authority or waste collector's list of accepted items first, because it differs from place to place. Many accept bottles, tubs and jugs by shape regardless of number. Empty and rinse containers lightly so food does not contaminate paper and other materials in the same bin. Follow local guidance on lids and caps, which some programmes want on and others want off. Leave out items the programme excludes, such as plastic bags in many kerbside systems, which can jam sorting machinery and are sometimes collected separately at shops.

Putting an unaccepted item in the recycling bin in the hope that it will be sorted out is sometimes called wishful recycling, and it can contaminate a batch of otherwise good material.

Plastics and the other materials in your home

The resin names in the table are also what separates familiar fibres from packaging plastics. Polyester, for instance, is the fibre form of PET, the same polymer as a code 1 bottle, as described in the Britannica entry on polyester. That is why some clothing and fabrics are made from recycled bottles, and it is also why a polyester garment behaves so differently from cotton, a comparison made in Cotton vs Polyester.

Reduce and reuse come first

Because recycling rates for most plastics are low, using less single-use packaging and reusing durable containers usually saves more material than perfecting sorting.