How we calculate carbon figures

1. What the figures mean

• Making this new is the kilograms of CO2e emitted to make one new unit, from raw materials to the factory gate (cradle to gate, life-cycle stages A1–A3). Delivery, use and end of life are not included. CO2e (carbon dioxide equivalent) counts every greenhouse gas as the amount of CO2 that would warm the planet as much.

• Avoids is the making-new figure minus the emissions of reuse: cleaning, repair, handling and transport. When an item's own reuse emissions are not known, we deduct 20% of the making-new figure. A study by the Rochester Institute of Technology found that remanufacturing an office workstation system caused 17% of the climate impact of making it new; simple resale usually emits less, so 20% keeps the figure on the cautious side.

• The comparison is always with buying the same product new. It assumes the item replaces a new purchase; a buyer who would have bought nothing, or something lighter, avoids less.

2. Where the numbers come from

• The product's own declaration. When the manufacturer publishes an Environmental Product Declaration (EPD) for the product line — a footprint checked by an independent verifier before it is published — we use its cradle-to-gate result and name it beside the figure.

• Otherwise, its type and weight. We multiply the item's weight by the typical carbon per kilogram of its kind of product (task chair, lateral file, meeting table…), the median of 170 published declarations from 26 manufacturers. Replicas and look-alikes never use a brand's declaration.

• Never its price. A resale price measures depreciation, not emissions, so we never estimate a pre-owned item from its price. When neither method applies, we show no figure.

3. How precise they are

Products of one kind differ, so each estimate shows a range, and figures are rounded to whole kilograms. A figure from a product's own declaration is more precise than one estimated from its type and weight; the source line says which you are looking at.

4. What we do not claim

We never call a product carbon neutral or climate positive, never offer avoided carbon as an offset, and never subtract it from anyone's footprint. These are estimates, not a certified product carbon footprint under ISO 14067.

5. Verification and review

The figures and the method behind them have not been independently verified by a third party. The underlying data was checked against its published sources in October 2026. We review the method and its data every year; the next review is due by October 2027. A description of the method and the evidence behind it are available on request.

6. For business buyers

If you report Scope 3 emissions, count a pre-owned purchase at the emissions of its reuse (shown in your Circadia carbon report), not at the making-new figure, and do not subtract avoided carbon from your emissions inventory.

7. Changes

• October 2026: figures now come from askotter's Carbon Calculator, using manufacturers' declarations and product type and weight. They replace earlier estimates made from resale prices.

8. Questions or corrections