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Verification attestation

getgrammage.com

Grammage attests that it measured the environmental footprint of this site on 1 October 2026, according to its published method, and obtained the result below.

Current attestation, valid until 1 October 2027

The result

91/ 100, grade A

≈ 0.03 g CO₂ eq. / page, 12× lighter than the average showcase site

≈ 0.03 g CO₂ eq. / page12× lighter than the average showcase site

measured by Grammage

Measured on
1 October 2026 at 21:58
Valid until
1 October 2027
Category
showcase site
Scope
the whole site, on average per page
Method
grammage-1, notation-2026.3
Tool
Grammage 0.79.0
Attestation no.
GRM-2026-C9634DB0
Signature
Ed25519, key resultats-2026-09

To put this result in context

A figure on its own does not say much, so here are the benchmarks that let you read it, the score Grammage gives by comparing the site with those of its category, then the carbon scale that Sustainable Web Design publishes for the very model Grammage uses, and finally the target that digital technology has to meet to stay within the Paris Agreement.

The Grammage grading, from A to F

Each site is compared with the pages of its category, based on the Web Almanac, so a page that weighs as much as the average gets 50, and it has to be as light as the leanest quarter of pages to reach 90 and grade A, which is the goal Grammage sets for every site.

  1. Afrom 90The goal
  2. Bfrom 70
  3. Cfrom 50
  4. Dfrom 30
  5. Efrom 10
  6. Funder 10
getgrammage.com, 91 / 100

The Sustainable Web Design carbon scale

It ranks a page from A+ to F on its grams per page view alone, without looking at what kind of site it is, and its thresholds were set so that the average web page, which transferred 2.4 MB in 2023 according to the HTTP Archive, about 0.36 g, falls into F. It is therefore a deliberately very demanding scale, which pushes the whole profession to build lighter, since an A requires staying under 0.079 g, that is an almost bare page.

getgrammage.com gets A+ there with ≈ 0.03 g, which is 12 times less than the average web page. This letter may look harsher than the Grammage score, and that is normal, because the two scales do not answer the same question. Sustainable Web Design measures the distance to an ideal page, whereas Grammage compares the site with the pages of its category, showcase site here, and also takes into account the number of requests, the size of the page, the good practices and the hosting. A site can therefore be among the leanest of its category and only have an average letter on this scale, without it being the sign of a badly designed site.

  1. A+up to 0.04 g
  2. Aup to 0.079 g
  3. Bup to 0.145 g
  4. Cup to 0.209 g
  5. Dup to 0.278 g
  6. Eup to 0.359 g
  7. Fmore than 0.359 gthe average web page
getgrammage.com, ≈ 0.03 g

The target to meet

To stay within the Paris Agreement, the International Telecommunication Union has set digital technology a 45% cut in its emissions between 2020 and 2030, in its standard ITU-T L.1470, and more and more telecom operators are aligning with it. For a site, Grammage aims for grade A, that is being at least as light as the leanest quarter of the pages of its category, and every letter gained on the Sustainable Web Design scale brings the site closer to that target. The detail of the calculation is on the The method page.

The official documents

These are the only documents that count for this attestation, and each new measurement replaces them. The SHA-256 fingerprint shown under each one lets you make sure that a file you were sent is the one published here, down to the byte.

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Attestation GRM-2026-C9634DB0, documents published on 1 October 2026.

What this attestation means

What Grammage attests

Grammage attests the result of a measurement, and only that measurement. Grammage loaded the pages of the site getgrammage.com itself in a real browser, from its own machines, then estimated the greenhouse gas emissions linked to displaying them according to the method described above, which is described in full on the The method page. The figure for the site is an average per page, weighted by page template and not by traffic, which Grammage does not know, and the comparison places it against the sites of the same category, based on the public benchmarks of the Web Almanac.

What it does not say

This attestation is not a certification, since in France only a body accredited by Cofrac can issue one, and it is not an environmental label within the meaning of directive (EU) 2024/825 either. It therefore does not judge the site as a whole, nor the company that publishes it, nor its activity, and it does not allow anyone to say that a site is “eco-friendly” or “responsible”. Its figures remain estimates, which describe the site as it was on the day of the measurement, and a site that changes a lot after that date may move noticeably away from them.

How long it is valid

An attestation is valid for twelve months from the date of the measurement. After three months it remains valid but its age is shown, here as on the badge, and after a year it no longer shows any figure until the site has been measured again. Each new verification replaces the previous one and its documents, and a withdrawn attestation disappears from this page, so what is published here is always what counts, and not an older document that might still be circulating.

Checking a document you were sent

A document is only valid if it is identical to the one published on this page. To check it, just compute its SHA-256 fingerprint and compare it with the one shown above, with the command shasum -a 256 attestation.pdf on macOS or Linux, or Get-FileHash attestation.pdf on Windows. The slightest change to the file, even a single character, gives a completely different fingerprint.

The two PDFs are also electronically signed by Solyzon, the publisher of Grammage, in the PAdES format that Acrobat and most readers can read. The reader then flags any change made after the signature, and it may say that the identity of the signatory is not verified, because this signature comes from our own certificate and not from a paid authority, which changes nothing about its strength.

Who issues it

Attestations are issued by Solyzon, which publishes Grammage. To report an error in a result or to contest an attestation, you can write to [email protected] stating the domain and the attestation number. The rest is governed by the terms of use (in French) and the legal notice (in French).