Plastics by the Numbers: What Recycling Codes Actually Tell You
Those little triangles with numbers on the bottom of plastic items are not a safety rating — they are a resin code that tells you what a product is made of. Once you can read them, a few small, low-regret swaps become much easier.
What the number in the triangle actually means
The chasing-arrows triangle with a number inside is a resin identification code. It was created to help sorting facilities, not to rate how safe a product is. So a low number does not mean "safer" and a high number does not mean "worse" — each one simply names a different family of plastic.
Knowing the code is handy for two everyday reasons. First, it hints at whether your local program is likely to accept the item for recycling. Second, it gives you a quick sense of which plastics are commonly used near heat and food, where many families like to limit avoidable exposure as a simple, low-regret choice.
A quick tour of codes 1 through 7
Here is the plain-language version of what each number usually points to and where you tend to find it at home.
- 1 — PET or PETE: water and soda bottles, clear food trays. Widely recycled. Designed for single use rather than repeated refilling or heating.
- 2 — HDPE: milk jugs, detergent bottles, many yoghurt tubs. Sturdy and commonly accepted by curbside programs.
- 3 — PVC or vinyl: cling films, some bottles, shower curtains, flooring. Rarely recycled curbside and often best limited around food and heat.
- 4 — LDPE: bread bags, squeezable bottles, plastic film. Recyclable mainly through store drop-off, not most curbside bins.
- 5 — PP (polypropylene): tubs, takeaway containers, straws, bottle caps. Increasingly accepted, generally considered a workhorse plastic.
- 6 — PS (polystyrene): foam cups, clamshell takeout boxes, some cutlery. Hard to recycle and worth avoiding for hot food.
- 7 — Other: a catch-all that includes polycarbonate and various newer plastics. "7" tells you very little on its own, so treat it as "check the rest of the label."
Which numbers to limit near heat and food
If you only remember one rule, make it this: heat is the variable worth watching. Warming plastic — in a microwave, dishwasher, or with hot food and drinks — can make it more likely that small amounts of certain compounds migrate into what you eat. This is why many guidance sources suggest reaching for glass or stainless steel for reheating and storage.
Codes 3 (PVC), 6 (polystyrene), and 7 (other, which can include polycarbonate) are the ones families most often choose to keep away from heat and oily or acidic foods. Some research has linked these plastics to compounds like phthalates and bisphenols that people may prefer to reduce where it is easy to do so. Codes 2, 4, and 5 are generally seen as lower-concern for everyday use, though the heat rule still applies.
Open the cupboard where you keep food containers. Pull anything stamped 3, 6, or 7 out of microwave-and-dishwasher rotation and use it for cool, dry storage instead — or retire it. Then microwave and reheat in glass or ceramic going forward. No shopping required; you are just changing which container does which job.
"BPA-free" is not the whole story
You will often see a code 7 item proudly labelled BPA-free. That is reassuring on the surface, but it is worth knowing that BPS and BPF are common substitutes with similar mechanisms, so "BPA-free" does not always mean a clean swap.
The most dependable move is to sidestep the question entirely for food and drink: choose glass or stainless steel for storage, reheating, and water bottles whenever it is practical. You keep your existing plastics for non-food jobs and lower avoidable exposure without overhauling your kitchen.
How to recycle smarter without overthinking it
Recycling rules are stubbornly local, so the number is a starting point rather than a guarantee. Most curbside programs reliably accept 1 and 2; many now take 5; films and bags (often 4) usually need store drop-off; and 3, 6, and 7 are frequently not accepted at all.
Two habits make the biggest difference: rinse containers so they are clean enough, and check your municipality's accepted-materials list once so you are not guessing each week. When in doubt, reducing how many single-use plastics enter your home in the first place beats trying to perfectly sort the ones that do.
Your one small step
Tonight, turn over the food containers you reheat in most often. If any are stamped 3, 6, or 7, move your reheating to a glass bowl or ceramic plate instead. It costs nothing, takes two minutes, and quietly lowers a bit of avoidable exposure for your family.
Common questions
Does a lower recycling number mean the plastic is safer?
Not really. The number is a resin identification code that names the type of plastic, not a safety score. It is more useful as a clue to whether an item is widely recycled and whether it is one many families prefer to keep away from heat and food.
Is it okay to microwave a container that says "microwave-safe"?
A microwave-safe label generally means the container should not warp or melt at those temperatures — it is about the container holding up, not a promise about what may transfer into food. Because heat can increase migration of some compounds, many people choose to reheat in glass or ceramic as a simple, low-regret habit.
Is BPA-free plastic a fully safe choice for water bottles?
BPA-free is a step some people value, but BPS and BPF are common substitutes with similar mechanisms, so it does not settle the question on its own. For drinks and food, glass or stainless steel sidesteps the issue more reliably.
What does the number 7 tell me?
Very little by itself — 7 is a catch-all "other" category that includes polycarbonate and various newer plastics. Treat it as a prompt to read the rest of the label and, for food use, to lean toward glass or stainless when you can.
Should I throw out all my plastic containers?
No need. A practical approach is to keep your current plastics for cool, dry, non-food storage and shift food reheating and hot-liquid storage to glass or stainless over time. Small, gradual swaps are more sustainable than a big purge.
Keep exploring
How everyday plastic is made and usedPET (code 1) explainedPVC and vinyl, up closePolystyrene and foam packagingBPA and other bisphenolsWhat "BPA-free" really coversStart small with the Micro Detox app
Micro Detox is an educational exposure reduction guide. It is not medical advice and does not diagnose, treat, prevent, or cure any condition. If you are pregnant, trying to conceive, or managing symptoms, speak with a qualified health professional.
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