Methodology
How we calculate this.
We want every number we show to be something you can trace. So here's an open explanation of how we estimate the CO₂e saved per swap — and what the numbers do and don't mean.
The core idea
When you take a piece from the shared pool, in many cases you don't buy a new one. The emissions that would have gone into producing that new item are avoided. Those avoided emissions are what we estimate.
The method
- A consequential life-cycle approach, aligned with the EU PEFCR for Apparel & Footwear.
- We count the production-to-retail footprint of the new garment a swap displaces.
- We apply a displacement rate of 64.6% (WRAP 2025) — not every swap actually replaces a new purchase.
- We subtract the swap's small in-person operating footprint.
- We exclude the use phase (wearing and washing happen either way, wherever the item comes from).
What the numbers are — and aren't
What they are
- Estimates with ranges
- Always "on average ~X kg" or "up to ~X kg"
- Transparent, reasoned, and versioned
What they aren't
- Exact measurements of your specific item
- An offset or compensation promise
- "Climate neutral" or "climate positive"
Sally does not offset anything and is neither "climate neutral" nor "climate positive". Swapping avoids emissions — it does not cancel them out.
Transparency note
These figures currently rest on a borrowed displacement rate and an assumed item mix. We're replacing them step by step with our own measured values. Treat the current numbers as a first version (v1).
Sources
- EU PEFCR for Apparel & Footwear
- WRAP (2025), displacement rate 64.6%
