Page weight
The total data a page downloads across HTML, scripts, styles, images, fonts, and third parties.
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What it is
Page weight is the sum of the bytes transferred to load a page: HTML, CSS, JavaScript, images, fonts, video, JSON, and third-party requests. Measure a cold navigation separately from a repeat visit, because a warm browser may satisfy much of the same page from cache without transferring those bytes again.
Reach for it when a site is painful on slow networks, expensive on mobile data, or quietly growing release by release. Chrome DevTools' Network panel gives the transferred total, and a performance budget can stop a pull request from adding another oversized image, font, or script unnoticed. The HTTP Archive publishes the median page weight across the web if you want a reference point outside your own site.
Gotcha: transferred size and resource size are different. Brotli can make JavaScript small on the wire, but the phone still expands, parses, compiles, and runs the larger file. Also split the total by resource type: one megabyte of JavaScript and one megabyte of images impose very different CPU costs.
Ask AI for it
Reduce this page's cold-load page weight. In Chrome DevTools Network, disable cache, reload with the Fast 4G throttling preset, export a HAR, and total the transferred bytes by HTML, JavaScript, CSS, images, fonts, data, and third parties. Remove unused requests, serve responsive images with srcset and sizes, subset and self-host WOFF2 fonts, code-split non-critical JavaScript with import(), and enable Content-Encoding: br for text assets. Add a size-limit budget pinned to the new transferred total and report before and after bytes by resource type.