www.mcmaster.com

The numbers

First visit

0.168 g CO₂e

Return visit

0.0047 g CO₂e

Hosting

unknown

LCP

1.20 s

CLS

0

TTFB

371 ms

At 10,000 views a month this page emits about 15.2 kg CO₂e a year, roughly 62 km in an average petrol car. The estimate assumes 75% new and 25% returning visitors, a measured cache reload ratio of 3%, and world-average grid intensity. How we calculate this

1. Convert and compress imagessave ~0.055 g/visit (492 kB)High impact · quick fix

   85 images (1.09 MB) ship in legacy formats (JPEG/PNG/GIF).

   Serve AVIF (or WebP) with responsive srcset sizes, and re-compress oversized files. AVIF typically halves JPEG weight at the same visual quality.

   • contour-transfers.png40 kB
   • Filtering-sprite-60.png40 kB
   • vented-socket-head-screws.png30 kB
   • Power-Transmission-Rotary-Motion-sprite-60.png29 kB
   • made-to-order-pins.png27 kB

   WSG 2.9: Optimize media to reduce resource use
2. Lazy-load below-the-fold mediasave ~0.014 g/visit (127 kB)Medium impact · quick fix

   20 below-the-fold images/iframes (255 kB) download immediately for every visitor.

   Add loading="lazy" to below-fold img and iframe elements (and keep it off the LCP image). Browsers then fetch them only when scrolling approaches.

   • contour-transfers.png40 kB
   • vented-socket-head-screws.png30 kB
   • made-to-order-pins.png27 kB
   • hinge-adjusters.png26 kB
   • Pipe-Tubing-Hose-and-Fittings-Catalog.png13 kB

   WSG 2.9: Optimize media to reduce resource use
3. 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
4. Remove references to broken resourcessave ~<0.001 g/visit (672 B)Advisory · quick fix

   2 requests answered 4xx/5xx on load: transfer and connections spent on nothing, on every single visit.

   Delete or fix the references (stale asset URLs, dead third-party tags). Each one is a request the page provably does not need.

   • cancel.pngHTTP 410 · 336 B
   • ex.pngHTTP 410 · 336 B

   WSG 4.4: Setup necessary error pages and redirection links
5. Remove the entry redirectAdvisory · quick fix

   The address that was scanned goes through 1 redirect before the document is served, ending at https://www.mcmaster.com/. 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://mcmaster.com/redirects to https://www.mcmaster.com/

   WSG 4.4: Setup necessary error pages and redirection links
6. Simplify the document structureAdvisory · larger effort

   The page renders 2548 DOM elements, above the 1,500 guideline. Large trees cost memory and CPU on every visitor's device.

   Flatten wrapper markup, render long lists virtually or paginate, and prefer semantic elements over nested divs.

   WSG 3.6: Ensure code follows good semantic practices

Where the bytes are

• Images1.10 MB · 94 req
• HTML31 kB · 1 req