Plastic Identification Tool
Plastic identification tool, no lab required.
A free Sustainable Design Studio tool. Cut a small offcut, drop it in water, answer a few questions about how it bends and looks. You get the most likely polymer plus the two next closest matches. Built for makers and educators sorting feedstock before they shred it.
How it works
Four steps, two minutes
You need a small clean offcut, a cup of plain tap water, and two minutes. Skip any question you cannot answer. The engine still narrows down from what it has.
Grab a clean sample
A pea-sized offcut works. Cut from a clean section so labels and adhesives do not throw the float test.
Drop it in water
A float-or-sink test splits the six common polymers into two groups. PP, HDPE and LDPE float. PET, PVC and PS sink.
Bend, squeeze, look
Answer follow-up questions about feel, flex, clarity, and what happens at a bend. Each answer narrows the result.
Read the verdict
You get a most-likely polymer plus the second and third closest matches. Useful for sorting feedstock before you shred.
Identify the polymer
Answer the questions below. Skip anything you cannot test. Works for the six most common household polymers: PET, HDPE, LDPE, PVC, PP and PS.
Three things to check
Density, mechanical behaviour, and appearance. Each plastic has a recognisable combination of the three, and a few quick checks are usually enough to narrow a household sample down to one of six polymers. This is the same routine recyclers and materials labs use, just compressed into a questionnaire.
Density
The most useful single test. PP, HDPE, and LDPE are less dense than water and float. PET, PVC, and PS sink. A cup of tap water splits the six polymers into two groups, which removes half the candidates straight away.
Mechanical behaviour
How the sample behaves when you bend, squeeze, or stretch it is the next strongest signal. HDPE feels waxy and turns white where you bent it. PP snaps more cleanly. LDPE stretches and springs back. PS is brittle and crinkly. PET feels tough with a bit of spring. PVC feels like vinyl, often slightly soft.
Appearance
Eyes alone get you a long way. PET is crystal clear and tough, the classic drink-bottle look. PP is slightly milky. PS is glassy and brittle. PVC has a vinyl feel and look. Some items give themselves away on sight: EPS foam trays are polystyrene, caps with a living hinge are almost always polypropylene.
The tool covers the six most common household polymers
Identification is limited to PET, HDPE, LDPE, PVC, PP, and PS. Most bottles, tubs, films, and foams you will run into are one of those six, which is why manufacturers default to them. Engineering plastics like ABS, polycarbonate, nylon, and acrylic are out of scope. Real-world items are often blends or carry additives like fillers and dyes, so the verdict is an educated guess, not a lab result.
Stuck on a tricky sample?
If the verdict does not match what you expected, send us a photo and a short description. We have run this routine on a lot of recycled feedstocks and can usually tell you what is actually in your sample.