www.stanford.edu

The numbers

First visit

1.17 g CO₂e

Return visit

0.698 g CO₂e

Hosting

unknown

LCP

1.24 s

CLS

0

TTFB

55 ms

At 10,000 views a month this page emits about 125.9 kg CO₂e a year, roughly 516 km in an average petrol car. The estimate assumes 75% new and 25% returning visitors, a measured cache reload ratio of 60%, and world-average grid intensity. How we calculate this

1. Audit third-party servicessave ~0.442 g/visit (3.32 MB)High impact · moderate effort

   12 third-party domains account for 6.63 MB (84% of the page).

   Remove services that no longer earn their place; load the rest on interaction (facades for embeds, delayed consent-gated tags). Each third party is also a privacy and performance dependency.

   • a2-us.storyblok.com4.97 MB
   • www.youtube.com1.00 MB
   • a-us.storyblok.com210 kB
   • t.contentsquare.net183 kB
   • www.googletagmanager.com170 kB
   • fonts.gstatic.com41 kB

   WSG 3.5: Treat third parties the same as first parties
2. Defer video and audiosave ~0.292 g/visit (2.19 MB)High impact · quick fix

   4.38 MB of audio/video downloads during initial page load; 11 videos preload data without preload="none".

   Never autoload media: use preload="none" with a poster image, load players on interaction, and stream in an efficient codec (AV1/HEVC).

   • nav_about_1280.mp41.01 MB
   • freecompress-vayu-loop.mp4873 kB
   • nav_healthandmedicine_1280.mp4592 kB
   • nav_healthandmedicine_1280.mp4592 kB
   • nav_research_1280.mp4541 kB

   WSG 2.9: Optimize media to reduce resource use
3. Fix caching for returning visitorssave ~0.152 g/visit (1.02 MB)High impact · quick fix

   On a repeat visit 4.09 MB of static assets were re-downloaded instead of coming from cache.

   Serve static assets with Cache-Control: public, max-age=31536000, immutable and versioned filenames so returning visitors download almost nothing.

   • nav_about_1280.mp4Cache-Control: public, max-age=31536000 · 724 kB
   • nav_admissionsaid_1280.mp4Cache-Control: public, max-age=31536000 · 691 kB
   • nav_research_1280.mp4Cache-Control: public, max-age=31536000 · 541 kB
   • nav_research_1280.mp4Cache-Control: public, max-age=31536000 · 541 kB
   • nav_athletics_1280.mp4Cache-Control: public, max-age=31536000 · 527 kB

   WSG 4.2: Optimize caching and support offline access
4. Reduce JavaScript payloadsave ~0.057 g/visit (426 kB)High impact · moderate effort

   26 scripts total 1.70 MB on the wire (5.90 MB decoded). Bundles this size usually carry a lot of unused code.

   Split bundles per route, tree-shake dependencies, and audit with a bundle analyzer or coverage profile. A 25% cut is a conservative target for bundles this size.

   • base.js477 kB
   • m=r78Drb240 kB
   • deb31d7b75181.js181 kB
   • js170 kB
   • m=root,base158 kB

   WSG 3.2: Minify and remove unused codeWSG 3.3: Modularize bandwidth-heavy components
5. Enable text compressionsave ~0.035 g/visit (265 kB)High impact · quick fix

   3 text resources (379 kB) are served without gzip/Brotli.

   Enable Brotli (or at least gzip) on the server or CDN for HTML, CSS, JavaScript, JSON and SVG. Typical reduction is ~70%.

   • www.stanford.edu223 kB
   • www.stanford.edu81 kB
   • www.stanford.edu75 kB

   WSG 4.3: Reduce data transfer with compression
6. Optimize web fontssave ~0.016 g/visit (121 kB)Medium impact · quick fix

   6 font files total 346 kB.

   Subset fonts to used glyphs, prefer one variable font over multiple weights, serve WOFF2 only, and consider system fonts for UI text.

   • EdictDisplayVariableItalicVF-s.p.1ce647svi1ah…146 kB
   • EdictDisplayVariableRomanVF-s.p.2dc6b11lxf86j…97 kB
   • KFO7CnqEu92Fr1ME7kSn66aGLdTylUAMa3yUBA.woff241 kB
   • 47df9ba1c7236d3b-s.p.137759vg1sbmi.woff229 kB
   • 60d78e3f57927495-s.p.3wpf_k_4rh3gf.woff229 kB

   WSG 2.11: Use optimized web typography
7. Serve images at the size they displaysave ~0.010 g/visit (76 kB)Medium impact · quick fix

   5 images are encoded at more than twice the pixels the layout shows, even accounting for this viewport's pixel density.

   Generate multiple sizes and let the browser pick with srcset/sizes; a 4000px original behind a 400px slot spends bandwidth no screen displays.

   • filters:quality(60)43 kB
   • filters:quality(60)43 kB
   • filters:quality(60)41 kB
   • filters:quality(60)34 kB
   • filters:quality(60)33 kB

   WSG 2.9: Optimize media to reduce resource use
8. Verify your hosting energyMedium impact · moderate effort

   This host has not published renewable energy evidence with the Green Web Foundation, so its energy source is unknown.

   Choose a provider listed in the Green Web Directory, or ask your current provider to publish evidence (and a carbon.txt). This cuts the data-center share of every single page view.

   • carbon.txtNo carbon.txt found at the site root; publishing one is the lightest first step.

   WSG 4.1: Use sustainable hosting
9. Set a page-weight budgetAdvisory · moderate effort

   At 7.87 MB per view this page rates F. The findings above list where the weight is.

   Agree a transfer budget (e.g. under 975 kB reaches a B), enforce it in CI, and re-scan after each change to hold the line.

   WSG 3.1: Set goals based on performance and energy impact
10. Remove the entry redirectAdvisory · quick fix

    The address that was scanned goes through 1 redirect before the document is served, ending at https://www.stanford.edu/. Every hop is a full round trip on a connection that has not warmed up yet.

    Point links, sitemaps and canonical tags at the final address, and make the host redirect in one hop rather than chaining http to https to www.

    • https://stanford.edu/redirects to https://www.stanford.edu/

    WSG 4.4: Setup necessary error pages and redirection links

Where the bytes are

• Audio / video4.38 MB · 43 req
• JavaScript1.70 MB · 26 req
• Images827 kB · 18 req
• Data (fetch)389 kB · 9 req
• Fonts346 kB · 6 req
• HTML128 kB · 2 req
• CSS86 kB · 6 req
• Data (XHR)3.2 kB · 3 req
• Other0 B · 1 req