Nothing hidden, by design.
This page documents, in full, how every sustainability score in the Finer index is computed — the formula, every constant, every default, and everything the score deliberately leaves out. The same reference tables that drive the scoring engine render the tables on this page.
1. What this score is — and is not
The Finer sustainability score is a cradle-to-gate life-cycle estimate of a garment's environmental cost, expressed on a 0–100 scale (100 = lowest estimated impact) with an A–E grade. It is computed from a small set of product-level inputs — fiber composition, garment mass, fabric origin, transport mode, certifications, and brand operating signals — mapped against secondary emission databases synthesized from the French Ecobalyse/ADEME methodology and PEF-aligned sources.
It is not a measured footprint of the individual item. No laboratory was involved; no supply chain was independently audited. Where primary data is missing, the model substitutes deliberately unfavorable defaults (see §4). For this reason, Finer never labels any product "sustainable," "green," or "eco-friendly" — products carry a number, a grade, and a fully disclosed calculation, nothing more.
If a product's fiber composition cannot be identified at all, the score is withheld entirely. Publishing a score built on an invented fiber mix would be an unsubstantiated environmental claim — the model returns nothing instead.
2. The formula
The pipeline aggregates the inputs into a raw environmental cost in Ecobalyse-style points, then normalizes to the consumer scale.
Manufacturing emissions
Garment mass (kg) times the share-weighted emission factor of each fiber (kg CO₂e/kg, cradle-to-fabric), scaled by a grid multiplier for the electricity mix where the fabric was made. Recycled fibers earn a ×0.50 discount on their emission factor (a Circular Footprint Formula approximation); organic natural fibers earn ×0.80.
Forty percent of a garment's cradle-to-fabric footprint — the wet-processing and spinning share — scales with grid intensity; the baseline is the ~530 g/kWh grid the emission factors implicitly assume.
Logistics emissions
A fixed 10,000 km hub-to-market distance times the transport mode's emission factor per tonne-km. Air freight is 20–40× worse than sea freight; the mode dominates this term entirely.
Penalties
Carbon accounting misses two of apparel's ugliest externalities. Synthetic fibers shed microplastics with every wash and persist in landfill for centuries — a flat penalty scales with the synthetic mass share. A second penalty prices the probability that the garment is exported as waste at end of life: 12.1% for synthetics, 4.9% otherwise.
Durability and certifications
The durability coefficient Cdur — bounded between 0.67 and 1.45 per Ecobalyse — modulates the footprint by how long the garment is likely to stay in use. It is derived from brand-level operating signals: live catalog size (SKU velocity, weight 0.65) and within-category price position (weight 0.35). Sub-1,000-SKU slow-fashion catalogs earn full credit; ultra-fast catalogs above 16,000 SKUs earn none. Secondhand listings receive the best coefficient outright — resale extends garment life by construction. Verified certifications multiply a discount (floored at ×0.80 combined, so certifications can never launder a bad base footprint).
Normalization
Raw points map log-linearly onto 0–100: 1.0 raw points → 100, 40.0 raw points → 0. Grades follow fixed bands: A ≥ 80 · B ≥ 60 · C ≥ 40 · D ≥ 20 · E ≥ 0.
3. The constants
Every table below is rendered from the exact reference object the interactive calculator runs on, itself a verbatim port of the scoring engine's reference data. Values change only via reviewed edits and a version bump.
Fiber emission factors
Paper ranges are collapsed to midpoints. "Synthetic" flags the fiber into the microplastic and end-of-life penalties. Water factors are listed for reference and do not enter the current score.
Grid intensity by origin
Transport emission factors
Garment mass by category
Certification discounts
Penalties, durability and normalization
4. Punitive defaults, explained
When a data point is missing, the model never guesses generously — it assumes the least favorable case that is still defensible:
- Unknown fabric origin → charged at a coal-heavy textile-hub grid of 612 g CO₂e/kWh, above the Chinese national average.
- Unknown transport mode → charged as air freight, the most polluting mode by an order of magnitude.
- Unknown category → a conservative 0.40 kg default mass.
- Missing brand data → zero durability credit, pushing Cdur toward its 1.45 maximum.
- Unidentifiable fiber → no score at all (§1).
This is deliberate. Defaults that flatter missing data would reward opacity; punitive defaults mean submitting real data can only maintain or improve a score — which is precisely the incentive a transparency index should create.
5. Trade-offs and limitations
- Recycled synthetics. Recycled polyester halves the extraction footprint — and still sheds microplastics in the wash. The model credits the first and penalizes the second; the two are never traded against each other.
- Secondary data. Emission factors are industry averages, not supplier measurements. Two garments with identical inputs score identically even if their real supply chains differ.
- Fixed logistics distance. The 10,000 km hub-to-market assumption favors comparability over precision; the transport mode, not the distance, dominates the term.
- Parsed materials. Fiber composition is extracted from retailer product text by deterministic parsing. Mis-labeled products can be mis-scored — which is what the dispute channel is for.
- Brand-level durability. Cdur proxies garment longevity from brand operations, not from physical testing of the item.
6. What is excluded
- Carbon offsets — always. The score measures the intrinsic physical emissions of the supply chain. Purchased offsets, "carbon-neutral" badges, and net-zero pledges are never factored in; regulators now sharply distinguish value-chain reductions from purchased credits, and so does this model.
- Consumer use phase. Washing and drying behavior varies too widely per household to attribute per product.
- Brand-level marketing claims. Only product-level data and verifiable certifications enter the calculation.
7. Data completeness
Every score ships with a completeness fraction recording how much of the result came from real data versus punitive defaults, weighted by each factor's leverage on the final number:
A low completeness score does not soften the grade — it flags exactly where a brand can supply data to correct it.
8. Versioning and disputes
The current model is s-mvp-v2. Every stored score records the model version it was computed under; when the model changes, the version is bumped and the catalog re-scored. Product pages scored under a different version than this page documents say so explicitly.
Any value on record can be disputed. Each product page carries a pre-filled dispute email listing every input; corrections with evidence — mill invoices, certification IDs, transport documentation — are re-scored under the same public model. There is no negotiation channel for the score itself, only for the data.
9. Sources
The methodology synthesizes, and its constants are transcribed from, the following primary frameworks and secondary sources:
- Ecobalyse — the French environmental-labelling methodology for textiles, ADEME / Ministère de la Transition Écologique.
- Product Environmental Footprint (PEF) and the PEF Category Rules for Apparel & Footwear, European Commission.
- EU Green Claims Directive, Unfair Commercial Practices Directive, and the Ecodesign for Sustainable Products Regulation (Digital Product Passport).
- Higg Materials Sustainability Index — methodology and published critiques (the model's natural-fiber corrections respond to the documented synthetic-fiber bias).
- International electricity grid-intensity factors (carbonfootprint.com; IEA Electricity 2026).
- Freight emission factors for sea, rail, road and air (Freightos / FreightAmigo CO₂ calculators; CO2everything).
- Fiber carbon and water footprint literature (Carbonfact; SELVANE; Hemp Foundation; CO2everything; peer-reviewed sources cited therein).
The full working paper — "Architectural Framework for an MVP Apparel Sustainability Scoring Metric" — including its complete works-cited list, is available on request via aaron@finer.fit.