Staring at a triangle of arrows on a yogurt tub and wondering whether it goes in the bin? Recycling symbols explained: most tell you what a package is made of, not whether your local collection accepts it.
Packaging labels are one small piece of the bigger picture of what is sustainability, and this guide helps you read them with confidence.
| Item | Value |
|---|---|
| Universal recycling symbol created | 1970 |
| Numbered plastic resin codes introduced | 1988 |
| ASTM International began administering the codes | 2008 |
| Standard revised to swap chasing arrows for a solid triangle | 2013 |
| Numbers in the plastic resin code system | Seven |
| Brands using the How2Recycle label | 525 (in 2023) |
These figures come from the Wikipedia entry on the resin identification code and a Mental Floss guide to recycling symbols. Details can change, so check the source before you rely on them.
The main kinds of recycling symbol
The universal recycling symbol is the looping-arrows triangle. According to Mental Floss, it was created in 1970 by University of Southern California student Gary Anderson as part of a contest tied to the very first Earth Day. Each arrow represents one of the steps in the recycling process.
The numbered triangle is the resin identification code. The Wikipedia entry says these symbols were created in 1988 by the Plastics Industry Association in the United States, and that ASTM International has administered them since 2008.
The third kind is a brand’s own instruction label. The same Wikipedia entry notes that the Sustainable Packaging Coalition created the How2Recycle project in 2008 in the United States and Canada, and that 525 brands were using the label in 2023.
- Plain chasing arrows: a generic recycling symbol.
- Numbered triangle: names the plastic resin used.
- Instruction labels: tell you how to handle each part of the pack.
What do the numbers 1 to 7 on plastic mean?
Mental Floss explains that the resin identification code uses seven numbers to identify the type of synthetic material used to make a container. Green Matters adds that the number is there to help recycling plants sort materials.
- PET or PETE: found in peanut butter jars, plastic soda and water bottles, microwavable food trays, and salad dressing bottles.
- HDPE: forms milk jugs, laundry detergent bottles, butter tubs, motor oil bottles, and some shopping bags.
- PVC: best known for pipes. Mental Floss says it is usually not accepted by curbside recycling programs.
- LDPE: mostly used in plastic films such as shrink wrap and bags.
- PP: has a high melting point that makes it great for containing hot liquids.
- PS: polystyrene, which Mental Floss describes as notoriously difficult to recycle.
- Other: a miscellaneous category for everything that did not fit into the last six slots.
Higher numbers generally mean fewer places will take the item. That is why the number is a clue about the material, not a promise about the bin.
Codes for paper, metal, glass and batteries
Plastic is not the only material with a code. The Wikipedia entry on resin codes says European Commission Decision 97/129/EC extends the system with recycling codes for other materials like batteries, paper, and glass.
The Wikipedia list of recycling codes gives examples of how the wider numbering works:
- 20, 21 and 22: corrugated cardboard, non-corrugated paperboard such as cereal boxes, and paper.
- 40: steel, such as food cans.
- 41: aluminium, such as soft drink cans.
- 70: clear glass.
Codes also vary by country. The same page says China’s polymer identification system has 140 identification codes, far more than the US plastics list.
Does a recycling symbol mean you can recycle it?
No. The Wikipedia entry states that resin codes do not indicate whether a product is recyclable. It adds that consumers frequently misinterpret them, which contributes to wishcycling: the contamination of recycling bins with unrecyclable goods.
The recycling codes page makes the same point: a code, chasing arrows logo or resin code is an explanation of what the item is made of, not an automatic indicator that the material is recyclable.
The design itself has changed. At the US Environmental Protection Agency’s recommendation, a 2013 revision to the ASTM standard replaced the chasing arrows with a solid triangle, but the old symbols are still widely used among manufacturers.
Sorting matters because plastics must be recycled separately, with other like materials, to preserve the value of the recycled material. Keeping materials clean and apart is what lets them return to use, which is the idea behind the circular economy.
How to read a packaging label step by step
- Look for instructions first. The How2Recycle label aims to remove guesswork by instructing consumers how to recycle the packaging and describing which parts can be recycled.
- Identify the shape. Plain arrows are generic; a number inside names the resin.
- Read the number or letters. Use the list above to match it to a material.
- Check local rules. Green Matters notes that different cities and towns tend to have different rules, and says you can safely assume haulers will take PET and HDPE (plastics 1-2) before it becomes a guessing game.
- Consider the form. Some communities instruct residents to look at the form of packaging, such as bottles, tubs and lids, rather than relying on the resin code.
- Leave out what the rules do not list. That keeps unrecyclable items from contaminating the bin.
If a pack leaves you doubtful every time, plastic free packaging is one way to sidestep the question where it is practical. How2Recycle labels also encourage consumers to check with local facilities to see which plastics each municipal recycling facility can accept.
Frequently asked questions
Is the plain chasing-arrows triangle the same as the numbered one?
Show answer
No. The number names the plastic resin. When a number is omitted, the arrows resemble the universal recycling symbol, a generic indicator of recyclability.
Why did the arrows change to a solid triangle?
Show answer
The Wikipedia entry says revisions replaced the arrows with a solid equilateral triangle to address consumer confusion about what the code means. The change came in the 2013 revision of the ASTM standard.
Which plastics are hardest to recycle?
Show answer
Mental Floss’s 2019 guide calls polystyrene (6) notoriously difficult to recycle and says the catch-all category 7 is rarely included in curbside recycling programs. Your local rules decide what is actually collected.
Do paper, metal and glass have recycling codes too?
Show answer
Yes. European Commission Decision 97/129/EC extends the code system to materials such as batteries, paper and glass, and the Wikipedia list gives examples like 40 for steel and 41 for aluminium.
