Brands that sell on sustainability have heavy websites. Almost nobody checks.
The typical one emits 1.78 g of CO2 per visit. 111 of the 113 I could measure fairly score an F.
Heavy, slow pages cost the typical company here about €3,900 a year. What does it cost?
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 median, 1.78 g, is 5.0× the worst passing grade.
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.
Month by month
I froze an earlier edition, 2026-Q3 (measured 2026-09-02), before this site went public. It stays in the archive as measured.
I re-measure every company monthly. From November 2026 I measure each company in its main country, and from the 2027-Q1 edition this is where the monthly line for the whole index will appear, with a line per company on its own page. What changed.
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)
By country: Australia (3) · Belgium (3) · Brazil (1) · Canada (1) · Denmark (7) · France (9) · Germany (7) · India (1) · Italy (2) · Japan (1) · Lithuania (1) · Mexico (1) · Netherlands (6) · New Zealand (1) · Norway (1) · South Korea (1) · Spain (2) · Sweden (7) · Switzerland (1) · United Kingdom (17) · United States (40)
Cite this: The Green Blind Spot, 2026-Q4 edition, Baba SEO. https://greenblindspot.com/2026-q4/