Edition 2026-Q4
About a 10-watt LED bulb left on for 22 minutes, every visit. Is that a lot?
The median sustainability-positioned brand's website emits 1.78 g of CO2 per visit, 5.0× the worst passing grade.
An independent index of how much CO2 the websites of sustainability-positioned brands emit.
See the full ranking. 32 more could not be measured fairly. How this is measured.
Why this matters
Companies that sell on sustainability measure their factories, their shipping and their packaging. Almost none of them measure their website. It is the one part of the footprint nobody checks, so nobody sees it.
This is not greenwashing. It is a blind spot. I set out to measure the websites of 145 companies that make public sustainability claims: certified B Corps, companies with validated science-based targets, eco consumer brands and climate tech. I used the same model websitecarbon.com uses. 113 could be measured fairly and are ranked here; the other 32 are listed by name on a page of their own.
A heavy website is also a slow website. Cutting the weight cuts emissions and load time, and a slow page is one more reason a visitor leaves before buying.
The cohort, lightest to heaviest
Grades A+ to E: up to 0.36 g. 2 companies here.
- A+up to 0.040 g0 companies
- Aup to 0.079 g0 companies
- Bup to 0.145 g1 company
- Cup to 0.209 g0 companies
- Dup to 0.278 g1 company
- Eup to 0.359 g0 companies
- Fabove 0.359 g111 companies
well under the medianunder the medianover the medianmore than 1.6× the medianmore than 2.6× the median
One bar per ranked company, ordered lightest to heaviest. Bars are calm below the cohort median and warm above it. The band along the bottom is every passing grade, A+ to E.
The lightest and the heaviest
Lightest 5
| 1 | MightybytesSustainable web | 0.11 g |
| 2 | Wholegrain DigitalSustainable web | 0.23 g |
| 3 | The GuardianMedia and telecoms | 0.48 g |
| 4 | EcosiaTechnology | 0.57 g |
| 5 | L'OrealBeauty and personal care | 0.61 g |
Heaviest 5
| 109 | Thousand FellFashion and apparel | 4.47 g |
| 110 | CotopaxiFashion and apparel | 4.56 g |
| 111 | Stella McCartneyFashion and apparel | 5.00 g |
| 112 | Beyond MeatFood and drink | 5.25 g |
| 113 | NIOAutomotive | 7.60 g |
By sector: median grams per visit
Each sector's median, heaviest first. Sectors with three or fewer ranked companies move a lot on one company, so read them with the count.
Movement since the last edition
I froze an earlier edition, 2026-Q3 (measured 2026-09-02), before this site went public. It stays in the archive as measured. From the next edition, this is where sites that got heavier or lighter will appear, with the size of the change.
Browse the index
By sector: Automotive (3) · Beauty and personal care (6) · Climate tech (10) · Energy (15) · Fashion and apparel (21) · Finance (5) · Food and drink (20) · Household goods (8) · Industrial (3) · Marketplaces (4) · Media and telecoms (3) · Retail (3) · Sustainable web (2) · Technology (8) · Transport and logistics (2)
By claim: B Corp certified (42) · Cleantech (32) · Eco-first brand (37) · Validated science-based climate target (23)
Cite this: The Green Blind Spot, 2026-Q4 edition, Baba SEO. https://greenblindspot.com/2026-q4/