The State of Web Vitals

Scripts per page

How many scripts the page runs and their over-the-wire weight.

Field data PhoneDesktopAll Scope All sites Q1 2026 edition · Desktop field outcomes
Metric LCP INP CLS
1

At a glance the headline numbers for Scripts per page

How many scripts the page runs and their over-the-wire weight.

26
script count
on the typical page
554 KB
script weight
on the typical page
1,009 KB
1 in 4 pages exceed this
script weight
94,748
sites measured
desktop field data

The typical page runs 26 scripts weighing 554 KB.

The State of Web Vitals · Q1 2026 · 94,910 sites · desktop field datacorewebvitals.io/state-of-cwv
2

Distribution & median CLS site count and median CLS at each level of scripts per page — n

0.00 0.04 0.08 0.11 0.15
0.1
0 9545 19089
0 1–2 3 4 5–7 8–11 12–18 19–29 30–48 49–77 78–125 >p98
Good (≤0.1) Needs improvement Poor (>0.25) Site count
The State of Web Vitals · Q1 2026 · 94,910 sites · desktop field datacorewebvitals.io/state-of-cwv
3

Passing CLS by scripts per page — n which level passes the CLS most often

Scripts per page — nSitesPassing CLSCLS
0 2,071 84% 0.01
1–2 2,354 79% 0.01
3 1,495 77% 0.02
4 1,808 82% 0.02
5–7 5,325 82% 0.02
8–11 7,714 81% 0.02
12–18 13,952 80% 0.02
19–29 17,317 78% 0.02
30–48 19,089 77% 0.03
49–77 13,478 76% 0.04
78–125 8,310 77% 0.03
>p98 1,835 70% 0.05
Good Needs Improvement Poor Faded rows: under 100 sites

Scripts per page — n 26. p75 48. p99 154. At the low end (0): CLS 0.01. At the high end (>p98): CLS 0.05. computed

The State of Web Vitals · Q1 2026 · 94,910 sites · desktop field datacorewebvitals.io/state-of-cwv
4

Distribution & median CLS site count and median CLS at each level of scripts per page — size

0.00 0.04 0.08 0.11 0.15
0.1
0 18705 37409
0 0.1–0.28 0.28–0.784 0.784–2.19 2.19–6.14 6.14–17.2 17.2–48.2 48.2–135 135–378 378–1057 1057–2959 >p98
Good (≤0.1) Needs improvement Poor (>0.25) Site count
The State of Web Vitals · Q1 2026 · 94,910 sites · desktop field datacorewebvitals.io/state-of-cwv
5

Passing CLS by scripts per page — size which level passes the CLS most often

Scripts per page — sizeSitesPassing CLSCLS
0 359 74% 0.03
0.28–0.784 86 90% 0.00
0.784–2.19 193 86% 0.00
2.19–6.14 281 84% 0.02
6.14–17.2 766 83% 0.01
17.2–48.2 1,768 90% 0.00
48.2–135 7,975 84% 0.01
135–378 22,157 83% 0.02
378–1057 37,409 78% 0.03
1057–2959 19,523 73% 0.04
>p98 1,842 70% 0.05
Good Needs Improvement Poor Faded rows: under 100 sites

Scripts per page — size 554 KB. p75 1,009 KB. p99 3.7 MB. At the low end (0 KB): CLS 0.03. At the high end (>p98): CLS 0.05. computed

The State of Web Vitals · Q1 2026 · 94,910 sites · desktop field datacorewebvitals.io/state-of-cwv
6

Why this matters for the Core Web Vitals, and where to start fixing it

Script weight is the most expensive weight. A kilobyte of JavaScript costs more than a kilobyte of image, because after the download it is parsed, compiled and executed on the main thread. That is the same thread that must answer every click and keystroke, which is why script totals track INP.

The count matters next to the bytes: every script is a potential long task and another spot for the main thread to stall. Most pages would lose nothing by deferring most of their scripts. The ones that truly must run early are rare.

How do scripts affect the Core Web Vitals?

Passing INP barely moves across the range: 97% at one end, 95% at the other. This signal does not separate passing sites from failing ones.

Go fix it 14 methods to defer JavaScript → Reduce unused JavaScript → JavaScript priority levels →
Related signals DOM size → Page weight & requests → Image source mix → Stylesheet loading mix → Chrome field data from 94,910 sites, representing millions of real page loads · How we measured