The carbon math behind our counters

The counter on our homepage is the same three lines of math we would show an auditor:

impact = Σ (per-unit carbon factor × units sold)

Each product has a fixed, conservative per-unit carbon saved factor — the lifecycle emissions of the plastic or conventional alternative it replaces, minus the lifecycle emissions of ours. We take the low end of published ranges on purpose. If our numbers are ever checked, we would rather be under than over.

We also publish the part most brands hide: the footprint of what we did sell. Manufacturing, packaging and shipping our own products emits carbon too. We estimate it at 8% of the carbon each product saves — deliberately generous — and show it as the amber meter under the big green number.

That ratio is the only number that really matters to us. Saving carbon while emitting carbon is fine; the ratio is what says whether the net is worth it. Today it stands at roughly 12× saved per unit emitted. Every material decision we make is judged against moving that ratio up.