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 · Phone 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
phone field data

The typical page runs 26 scripts weighing 554 KB.

The State of Web Vitals · Q1 2026 · 94,910 sites · phone 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 · phone 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 92% 0.00
1–2 2,354 88% 0.00
3 1,495 87% 0.00
4 1,808 89% 0.00
5–7 5,325 90% 0.00
8–11 7,714 90% 0.00
12–18 13,952 92% 0.00
19–29 17,317 90% 0.00
30–48 19,089 88% 0.00
49–77 13,478 88% 0.00
78–125 8,310 88% 0.00
>p98 1,835 80% 0.01
Good Needs Improvement Poor Faded rows: under 100 sites

Scripts per page — n 26. p75 48. p99 154. At the low end (0): CLS 0.00. At the high end (>p98): CLS 0.01. computed

The State of Web Vitals · Q1 2026 · 94,910 sites · phone 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 · phone 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 82% 0.00
0.28–0.784 86 93% 0.00
0.784–2.19 193 98% 0.00
2.19–6.14 281 95% 0.00
6.14–17.2 766 95% 0.00
17.2–48.2 1,768 97% 0.00
48.2–135 7,975 95% 0.00
135–378 22,157 93% 0.00
378–1057 37,409 89% 0.00
1057–2959 19,523 83% 0.00
>p98 1,842 70% 0.02
Good Needs Improvement Poor Faded rows: under 100 sites

Scripts per page — size 554 KB. p75 1,009 KB. p99 3.7 MB. Spearman with CLS r = +0.35. At the low end (0 KB): CLS 0.00. At the high end (>p98): CLS 0.02. computed

The State of Web Vitals · Q1 2026 · 94,910 sites · phone 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?

Scripts per page correlates with the INP. Script count separates passing sites from failing sites more than script weight does. Where the script count is low, 73% of sites pass the INP. Where it is high, 86% do. The rise is gradual.

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