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, which can cost several times more and take 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. We credit avoided emissions only to the items that genuinely changed hands.
Equivalences are illustrative only and stated with their basis. We use different bases on purpose, because a car's tailpipe emissions and a person's total consumption footprint are different things. They are not part of the assessment result, which 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 let us build the most accurate counterfactual we could: what would actually have happened to these garments, and to their users' purchasing behaviour, if the swap platform didn't exist.
We reviewed the published range of displacement rates, meaning the share of swaps that genuinely replace a new purchase, and chose the most conservative defensible value, since The Swap Club does not yet have primary user data of its own. 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. We took the most conservative defensible displacement rate in the published range rather than the most flattering one, so the result would stand up to questions 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 more than triples, without a single new data point.
The literature offers a wide range. Published substitution factors run from 29% to 85% (Stevenson & Gmitrowicz 2012; Nørup et al. 2019; Castellani et al. 2015; Farrant et al. 2010, as compiled in Klooster et al. 2024), and several published LCAs simply assume 1:1. We used the lowest figure in that range, because The Swap Club has no primary user data of its own yet. We don't take credit for an assumption we can't evidence.
We could have published 471.7 tonnes and cited a peer-reviewed paper for it. We published 136.8 instead, because that is the number The Swap Club can defend.
Garments diverted from waste also avoid end-of-life emissions. This is a real saving, but counting it alongside avoided new production risks claiming the same benefit twice. We left it out of the total until we can settle that double-counting question with the founder's own survey data.
This is a gross avoided-emissions figure: it measures the production emissions displaced by swapping, not The Swap Club's net footprint. We have not deducted the operation's own logistics and venue emissions. They are small next to garment production, but we think 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. Treat it as 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 we label it 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, after the number The Swap Club has actually earned.
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 will still be standing.
This matters most at scale. Accelerators, funds and impact investors increasingly need the startups in their portfolios to back up their environmental claims, whether the question comes from a funder, an auditor or a due diligence team. 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: