How Better Cart works

Two sources of truth, one seamless experience.

Footprint Protocol tags (verified)

The Footprint Protocol is an open standard that lets brands publish product carbon data directly on their product pages as HTML meta tags. When Better Cart finds these tags, it reads the exact lifecycle CO₂e figure certified by the brand.

<meta property="fp:product"   content="Fairphone 5" />
<meta property="fp:co2e"      content="29.4" />
<meta property="fp:co2e:unit" content="kg" />
<meta property="fp:scope"     content="lifecycle" />
<meta property="fp:certifier" content="PRé Consultants" />

Standardised estimation protocol (best-guess)

When no fp: tags are found, Better Cart runs a three-tier estimation protocol based on GHG Protocol Scope 3 Category 1 methodology, ecoinvent 3.x emission factors, Higg MSI 2023 data, and US EPA USEEIO v2.1 spend intensities.

Tier 1 Confidence: 65–88%

Material-based hybrid

Requires weight + material composition signals from the page. CO₂e = Σ(material_mass × emission_factor) × manufacturing_multiplier + transport.

Tier 2 Confidence: 40–64%

Weight-scaled category average

Requires product weight. CO₂e = weight_kg × category_intensity (kg CO₂e / kg). Category intensities from ecoinvent 3.9.

Tier 3 Confidence: 15–39%

Spend-based EEIO

Price × USEEIO v2.1 spend intensity for the product's NAICS category. Least accurate but still directionally useful.

Alternatives matching

Once a footprint is established (verified or estimated), Better Cart queries its product catalogue for lower-CO₂e alternatives in the same category. Products are ranked by their CO₂e score relative to the category average, and the top 3 greener options are shown in the banner.