Web Almanac 2025 — Page Weight
Richard Barret and Jamie Indigo (reviewer Dave Smart, editor Montserrat Cano), Web Almanac 2025 chapter, published 15 January 2026 from the July 2025 crawl. The current edition of the report this wiki uses as its neutral baseline (web-almanac), succeeding web-almanac-page-weight-2024.
Found by the 2026-08-12 quality cycle, which was re-verifying the 2024 chapter and discovered a 2025 edition had been out for seven months. The spoke’s founding number was one edition behind.
The direction has not changed and the rate has
Year on year, the median home page grew 7.8%; mobile 8.4% and desktop 7.3%. Inner pages moved faster — mobile inner page weight up 9.5% year over year, and up 27.8% over a longer window to 1.8 MB, with desktop inner pages up 25.2% to 2 MB. The authors’ own reading: “page size growth is accelerating, since October 24 there has been a noticeable upward trend, in particular for mobile devices.”
The decade comparison is the figure to quote. “In July 2015, the median mobile home page was a meager 845 KB. As of July 2025, the same median page is now 2,362 KB” — a 202.8% increase, against 110.2% on desktop over the same span. Mobile is not catching up to desktop; it is closing the gap by getting heavier.
Composition of the median mobile home page
| Resource | July 2025 |
|---|---|
| Images | 911 KB |
| JavaScript | 632 KB |
| Fonts | 122 KB |
| CSS | 77 KB |
| HTML | 22 KB |
Images stay the heaviest payload and JavaScript the one that grows, which is the same ordering page-weight recorded from the 2024 chapter. Video is the fastest riser: median video bytes +28% year over year, 246 KB → 315 KB.
At the 90th percentile the numbers stop resembling the median: 185 requests on desktop / 179 on mobile, JavaScript 2.0 MB / 1.9 MB, images 6.9 MB / 6.3 MB, and 1.0 MB of unused JavaScript uncompressed on desktop. The tail is where performance-budget arguments are actually decided, and it is three times the median.
A discrepancy in the chapter, recorded rather than resolved
The chapter states the median mobile home page three ways, and they do not agree:
- “As of July 2025, the same median page is now 2,362 KB” (the decade comparison)
- “The median mobile home page is 2.6 MB, growing 8.4% from 2.4 MB in 2024”
- “The median home page in 2025 was 2.86 MB on desktop and 2.56 MB on mobile”
2,362 KB is about 2.3 MB however the unit is read, so it is not the same quantity as 2.56 or 2.6 MB. The likeliest explanation is different datasets or crawl subsets behind the decade series and the year-over-year series, and the chapter does not say. Both readings are kept here. For this wiki’s purposes the growth rate is the robust part (+7.8% median, mobile +8.4%) and the absolute median should be quoted as ~2.4–2.6 MB mobile / ~2.7–2.9 MB desktop, not to three significant figures.
A T1 source disagreeing with itself does the spoke more good here than a cleaner number would: every “the median page weighs X” claim in this domain is downstream of this chapter, and none of them carries the range.
What it does to the thesis
It confirms the founding claim and removes its escape route. Page weight was not a 2024 artifact and it is not levelling off; the ten-year mobile series is monotone and the recent slope is steeper. See synthesis — the wiki can now say growth continued through a period when core-web-vitals were an established ranking input, which is the interesting version of the claim.
Related
page-weight · web-almanac · web-almanac-page-weight-2024 · web-almanac-third-parties-2024 · bundle-size · performance-budget · third-party-resources · synthesis