Every circular business believes it saves something. Very few can say how much, in a number that holds when someone asks where it came from. We built that number for a clothing-swap platform in Amsterdam.
The Swap Club is a circular fashion initiative based in Amsterdam. It runs a clothing-swap platform for people who have clothes they no longer wear but want to give them a second life rather than throwing them in the textile bin, who like refreshing their wardrobe, and who enjoy wearing second-hand. Instead of discarding garments, members swap them, keeping clothing in use and out of the waste stream.
The Swap Club's business model is circular by design, but they needed a way to explain their environmental impact in concrete terms. As a circular startup, they follow accelerator programs closely, and many of these programs increasingly ask for impact assessments.
The Swap Club knew that building a clothing-swap platform creates real environmental value, but they needed reliable, defensible numbers to show their partners, stakeholders, and investors. At the same time, they were at an early stage, not yet ready to commission a full LCA that costs 10k+ and takes months.
What they needed was a starting point: a screening-level impact model that would make their environmental story credible and accessible, without the cost and complexity of a full assessment.
28,000 is the founder's event-based estimate of items actually swapped. It excludes collected items that were stored, rejected, or sent on for recycling — avoided emissions are credited only to items that genuinely changed hands.
Equivalences are illustrative only and stated with their basis. They are not part of the assessment result — the assessment result is 136.8 t CO₂e.
We worked closely with the founder through a series of meetings to understand The Swap Club's business model from end to end. This allowed us to build the most accurate counterfactual possible — what would actually have happened to these garments, and to their users' purchasing behaviour, if the swap platform didn't exist.
We screened their operations to determine the right displacement rate for The Swap Club's specific users (the share of swaps that genuinely replace a new purchase). We then sourced category-specific emission factors from reliable databases and peer-reviewed studies, including ADEME Base Empreinte, Carbonfact, and published LCA research, mapping each product category correctly.
Throughout, we made deliberately conservative choices — using the most defensible displacement rate in the literature rather than the most flattering one — to ensure the result could withstand scrutiny from any investor or reviewer. Finally, we cross-checked our results against peer-reviewed academic studies and confirmed our impact numbers fell within the established range.
The single most powerful assumption in any reuse model is the displacement rate: how many swaps genuinely replace a new purchase. Move that one dial and the headline changes by a factor of three — without a single new data point.
The literature offers a wide range. Vinted and the EU-funded SOLSTICE work use 40%. One academic study assumes 100%. We used the lowest defensible figure in the range, because The Swap Club has no primary user data of its own yet — and an assumption you can't evidence isn't one you should take credit for.
We could have published 471.7 tonnes and cited a peer-reviewed paper for it. Instead we published 136.8 — the number that survives the follow-up question.
Garments diverted from waste also avoid end-of-life emissions. That's real — but counting it alongside avoided new production risks claiming the same benefit twice. Until that double-counting question is resolved with the founder's own survey data, it stays out of the total.
This is a gross avoided-emissions figure: it measures the production emissions displaced by swapping, not The Swap Club's net footprint. The operation's own logistics and venue emissions are not deducted — they are small relative to garment production, but stating the boundary is part of stating the number.
× 4.89 kg CO₂e per swap, from this assessment's category mix and a 29% displacement rate. A planning estimate — a different assortment or user base changes the per-swap factor. Car equivalence at ~1.7 t CO₂e per EU average passenger car per year.
if The Swap Club reaches its target of 1 million swaps per year.
This is what the same model returns at the company's stated growth target, holding the current category mix and the same 29% displacement rate constant. It is a target-based projection, not achieved impact, and it is labelled that way everywhere it appears — including in The Swap Club's own investor materials.
Most impact decks lead with the projection. We put it last, behind the number that's real.
A number you can defend is worth more than a number that impresses — the moment someone asks "how did you get that?", only one of them is still standing.
This matters most at scale. Accelerators, funds, and impact investors increasingly need the startups in their portfolios to show environmental impact that holds up — to funders, to auditors, to due diligence. A claim that collapses under questioning isn't just a weak number; it's a reputational risk for everyone who backed it. That's the gap we close: credible, defensible impact data a whole portfolio can stand behind.
CarbonSquare is built for people in exactly that position: