What we measure
We load your homepage with Google Lighthouse on a simulated phone and break the transfer down by resource type. The report shows a stacked bar of where the bytes go and a table of the heaviest third parties.
- Total page weight and number of requests.
- Bytes per type: document, scripts, stylesheets, images, fonts, media and third-party resources.
- JavaScript from your own domain versus third parties.
- Unused JavaScript and CSS, render-blocking resources and web font loading.
- HTTP/2 or HTTP/3 use, and an approximate carbon estimate per page view.
Why weight matters
Heavier pages take longer to load on mobile networks, cost visitors on limited data plans and use more energy. Weight is not the only factor — a light page can still be slow if a script blocks rendering — but it is the easiest one to see and to reduce. For a brochure-style firm website there is rarely a good reason to download several megabytes on the homepage.
The number of requests matters too. Each file needs to be requested and, from a new host, needs a new connection. Ten tracking and widget hosts on one page add up to real delays, especially before HTTP/2 connection reuse kicks in.
Where to cut first
Images are usually the largest share: convert them to WebP or AVIF, resize them to the size they are displayed and lazy-load those below the first screen. Next come scripts: page builders, sliders, animation libraries and widgets you no longer use. The unused JavaScript and CSS figures tell you how much of what loads is never executed on this page.
Fonts are often forgotten. Four weights of two families can easily exceed the weight of the text they display. Use one or two weights, subset them to the characters you need, self-host them and use font-display: swap. The third-party table shows which outside services cost the most bytes and main-thread time, so you can decide whether each one earns its place.
Keeping the weight down
Page weight tends to creep up over time as new images, widgets and tracking tags are added. Set a simple budget, for example a maximum homepage weight and number of third-party hosts, and check it after every larger change. Re-running this check takes a minute and shows immediately which new element made the page heavier.