How to read an index score

ecogpt.coPublished Oct 19, 2026 · 2 min read

A company's score is a weighted sum of six pillars, each 0–100, with a confidence grade attached. Here is what the number means, why a 70 with a D grade is not a 70 with an A grade, and the three bands the index uses.

Weights: carbon 25%, efficiency 20%, transparency 20%, water 15%, commitments 10%, conduct 10%.
65 and above is a leader, 45–64 the middle, below 45 a laggard.
Grades run A (disclosed with method) to D (little data); the company grade is the weighted average of its pillars.
Scores measure practice, not size: a hyperscaler with a middling score has a far larger footprint than a lab with a high one.

The number

Every company's score is computed, not assigned. Six pillars are scored 0–100 against published rubric anchors on the methodology page, multiplied by fixed weights and summed. Carbon carries 25%, efficiency and transparency 20% each, water 15%, commitments and conduct 10% each. Mistral's 75 is 0.2 × 70 + 0.25 × 85 + 0.15 × 55 + 0.2 × 88 + 0.1 × 55 + 0.1 × 85, rounded. Changing a pillar input changes the score; there is no other lever.

The bands

Leader, 65 and above: discloses real numbers and runs mostly on clean power. Still has a footprint, but you can see it. Mistral, Google, Apple.

Middle of the pack, 45–64: some disclosure or clean-energy commitments, offset by rising emissions or blind spots. Most of the hyperscalers and the better Chinese clouds.

Laggard, below 45: little or no disclosure, fossil-backed capacity, or active disputes with regulators and communities. The pure labs, the image service, the neoclouds, and xAI.

The grade

Each pillar carries a confidence grade: A for company-disclosed figures with a method or independent measurement, B for company-level disclosure that is not AI-specific, C for figures derived from hosts, architecture or press, D for no disclosure at all. The company grade is the weighted average. Apple's 70 carries a B; Anthropic's 42 a D. A high score with a D grade means the company looks acceptable on the little it publishes, and the index says so on the profile: "In plain words".

What the score is not

A measure of absolute impact. Mistral's whole flagship model emitted 20 kt; Google's company emitted 11,500 kt. The score rewards disclosure, efficiency, clean supply, water design, dated targets and good conduct, all of which a small company can have and a large one can lack. The hardware block and the "sort by" options on the rankings show the scale separately.

How to use it

Read the band first, then the grade, then the pillar that surprises you. A leader with a low water pillar (Google) and a laggard with a high efficiency pillar (DeepSeek) are both telling you something specific, and the evidence under each pillar says what.