You’ve seen the claim: “The average person eats a credit card’s worth of plastic every week.” Five grams. It’s in headlines, nonprofit campaigns, and roughly every third microplastics video on the internet.
It’s wrong — by about three orders of magnitude. And we’re the anti-plastic site, so hearing it from us should mean something.
Where the number came from
A 2019 media campaign promoted an estimate later formalized in a 2021 paper: combine the counts of microplastic particles found in water, salt, shellfish and a few other foods, assume generous particle sizes and masses, and you get up to ~5 grams per week. A credit card weighs about 5 grams. Headline born.
Where it falls apart
The estimate’s particle counts weren’t crazy — the mass per particle was. The calculation effectively assumed people swallow large plastic fragments at the top end of the size range, when nearly everything we actually ingest is dust-fine or smaller.
When other researchers redid the math with realistic particle masses:
- A 2021 Environmental Science & Technology lifetime-accumulation model put median adult intake around a few micrograms to low milligrams per week — not five grams.
- A 2022 reanalysis published as a direct response concluded the credit-card figure overestimates by several thousand-fold, and that at realistic rates it would take decades to centuries to ingest one card’s mass, not seven days.
To be concrete: the honest range is something like a grain-of-salt’s worth per week, not a credit card — with enormous person-to-person variation depending on (you guessed it) bottled water habits and heated-plastic habits.
Why we’re telling you this
Three reasons, and they’re load-bearing for everything else on this site:
- Bad numbers eventually get debunked — loudly. When the credit-card stat collapses in public, every legitimate concern attached to it takes splash damage. Asbestos didn’t need exaggeration. Neither does this.
- You can’t make good decisions with fake magnitudes. If you believe you’re eating 5g a week no matter what, why bother changing anything? The truth — that your dose is small and largely determined by a handful of habits you control — is far more actionable.
- Trust is the product here. We want you to believe our scary numbers — the quarter-million particles per liter of bottled water, the 4.5× cardiac risk association, the spoon of plastic in the brain. Those are real. They only stay believable if we burn the fake ones in public.
The honest bottom line
The mass you ingest is small. The particle counts are enormous (trillions of nano-scale particles), they’re accumulating in tissue faster every decade, and the strongest health signals don’t depend on mass at all — a nanoplastic in an artery wall does damage by being there, not by weighing something.
So: smaller number, same conclusion. Cut the top exposure routes — they’re ranked here — and skip the panic. Panic isn’t a strategy. A checklist is.