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https://www.royal.uk

Performance

· 17 checks — Lighthouse + waterfall + sustainability rolled into one auditable list.
SCORE
86
GRADE
B
FIX
1
REVIEW
4
PASS
10
INFO
2

Performance-focused optimization plan with CWV assessment, top offenders, and time estimates

Mobile Desktop
59
Performance Overall performance score (0–100) based on Core Web Vitals and other metrics. 90+ is good.
96
Accessibility Measures how accessible the page is for users with disabilities. Checks color contrast, ARIA labels, and semantic HTML.
100
Best Practices Checks for modern web development best practices including HTTPS, no console errors, and secure JavaScript.
92
SEO Measures basic SEO optimizations: meta tags, crawlability, link text, and mobile friendliness.

First Contentful Paint First Contentful Paint — how long until the browser renders the first piece of content. Under 1.8s is good.

3.35 s

Largest Contentful Paint Largest Contentful Paint — how long until the largest visible element loads. Under 2.5s is good.

8.39 s

Total Blocking Time Total Blocking Time — total time the main thread was blocked, preventing user input. Under 200ms is good.

297 ms

Cumulative Layout Shift Cumulative Layout Shift — measures visual stability. How much the page layout shifts during loading. Under 0.1 is good.

0.000

Speed Index Speed Index — how quickly content is visually displayed during load. Under 3.4s is good.

5.14 s

Time to Interactive Time to Interactive — how long until the page is fully interactive and responds to user input. Under 3.8s is good.

8.40 s

Page Load Progression

375 ms
750 ms
1.1 s
1.5 s
1.9 s
2.2 s
2.6 s
3.0 s
Checks
17
10 PASS 4 REVIEW 1 FIX
D
JS Execution Cost
Action
2129ms total JS execution
FIX
2129ms total JS execution
Warning::
https://www.royal.uk/: 730ms CPU time
Warning::
Unattributable: 354ms CPU time
Warning::
https://consent.cookiebot.com/e6cc3f6f-4a95-47e7-8...: 322ms CPU time
Warning::
https://www.royal.uk/sites/default/files/js/js_sks...: 312ms CPU time
Warning::
https://consent.cookiebot.com/uc.js: 274ms CPU time
Warning::
Third-party scripts: 1086ms (51% of total)

Main Thread Breakdown

Script Evaluation 32% Style & Layout 28% Other 22% Script Parsing & Compilation 6% Parse HTML & CSS 6% Rendering 3%
ScriptTotalScriptingParse/CompileParty
https://www.royal.uk/730ms17ms3ms1st
Unattributable354ms7ms0ms3rd
https://consent.cookiebot.com/e6cc3f6f-4a95-47e7-8b38-0232754863a7/cc.js?renew=false&referer=www.royal.uk&dnt=false&init=false322ms144ms37ms3rd
https://www.royal.uk/sites/default/files/js/js_skslNSOfxlTUCgjg_JXTTLpJ-Pa54XwbsRG2ar-Ey_A.js?scope=footer&delta=0&language=en&theme=kpp&include=eJwdjVESgyAMRC8E5khOJKmmUsIE1NLTV_Oz8_Z97CY1BrKjYp5IMOs64Ru_Ya8VMCU1Ei3eNkZic5TykiJ9xNWE3JgOzPHipUnnFj9cDveN0dL24JxUd-FFO9yrHDL-BjwRTuGrgad__wEuBjhK312ms176ms45ms1st
https://consent.cookiebot.com/uc.js274ms246ms11ms3rd
https://www.googletagmanager.com/gtm.js?id=GTM-WBJ2Q8R137ms101ms36ms3rd
B
Page Weight Budget
1.2 MB transferred, 27 requests
REVIEW
1.2 MB transferred, 27 requests
Info::
Page weighs 2.4 MB (1.2 MB transferred)
Info::
27 HTTP requests
Info::
Estimated 0.24 g CO2 per page load
1.2 MB / 2.4 MB budget
1.2 MB transferred
27 requests
0.24 g CO2 per page load
Images 672.4 KiB 57%
JavaScript 350.9 KiB 30%
Fonts 88.1 KiB 7%
Other 44.1 KiB 4%
CSS 14.7 KiB 1%
HTML 11.0 KiB 1%
Other 937 B 0%
0 2.4 MB 4.9 MB
Under budget
B
Image Optimization
11 images, 0 KB saveable
REVIEW
11 images, 0 KB saveable
Info::
All images are well-optimized
11 images 672 KB
0 oversized -0 KB
9 legacy format
0 missing dimensions CLS risk
C
JS Bundles
Action
7 scripts, 225 KB unused
REVIEW
7 scripts, 225 KB unused
Warning::
https://www.googletagmanager.com/gtm.js?id=GTM-WBJ...: 70 KB unused (59%)
Consider code splitting or tree shaking to reduce unused code.
Warning::
https://www.royal.uk/sites/default/files/js/js_sks...: 64 KB unused (70%)
Consider code splitting or tree shaking to reduce unused code.
Warning::
https://www.royal.uk/sites/default/files/js/js_sks...: 64 KB unused (70%)
Consider code splitting or tree shaking to reduce unused code.
Warning::
https://consent.cookiebot.com/e6cc3f6f-4a95-47e7-8...: 26 KB unused (24%)
Consider code splitting or tree shaking to reduce unused code.
Info::
Total unused JavaScript: 225 KB
225 KB unused JavaScript

Downloaded but never executed on this page.

ScriptSizeUnusedMinifiedParty
https://www.googletagmanager.com/gtm.js?id=GTM-WBJ2Q8R120 KB70 KB (59%)✓3rd
https://www.royal.uk/sites/default/files/js/js_skslNSOfxlTUCgjg_JXTTLpJ-Pa54XwbsRG2ar-Ey_A.js?scope=footer&delta=0&language=en&theme=kpp&include=eJwdjVESgyAMRC8E5khOJKmmUsIE1NLTV_Oz8_Z97CY1BrKjYp5IMOs64Ru_Ya8VMCU1Ei3eNkZic5TykiJ9xNWE3JgOzPHipUnnFj9cDveN0dL24JxUd-FFO9yrHDL-BjwRTuGrgad__wEuBjhK92 KB64 KB (70%)✓1st
https://www.royal.uk/sites/default/files/js/js_skslNSOfxlTUCgjg_JXTTLpJ-Pa54XwbsRG2ar-Ey_A.js?scope=footer&delta=0&language=en&theme=kpp&include=eJwdjVESgyAMRC8E5khOJKmmUsIE1NLTV_Oz8_Z97CY1BrKjYp5IMOs64Ru_Ya8VMCU1Ei3eNkZic5TykiJ9xNWE3JgOzPHipUnnFj9cDveN0dL24JxUd-FFO9yrHDL-BjwRTuGrgad__wEuBjhK0 KB64 KB (70%)✓1st
https://consent.cookiebot.com/e6cc3f6f-4a95-47e7-8b38-0232754863a7/cc.js?renew=false&referer=www.royal.uk&dnt=false&init=false108 KB26 KB (24%)✓3rd
https://consent.cookiebot.com/uc.js27 KB—✓3rd
https://consentcdn.cookiebot.com/consentconfig/e6cc3f6f-4a95-47e7-8b38-0232754863a7/royal.uk/configuration.js1 KB—✓3rd
https://www.royal.uk/libraries/lazysizes/lazysizes.min.js4 KB—✓1st

Consider code splitting or tree shaking to reduce unused code.

Why this matters

This bundle has high unused code — code-split or tree-shake to ship only what executes.

Source: web.dev / Lighthouse coverage

Consider code splitting or tree shaking to reduce unused code.

Why this matters

This bundle has high unused code — code-split or tree-shake to ship only what executes.

Source: web.dev / Lighthouse coverage

Consider code splitting or tree shaking to reduce unused code.

Why this matters

This bundle has high unused code — code-split or tree-shake to ship only what executes.

Source: web.dev / Lighthouse coverage

Consider code splitting or tree shaking to reduce unused code.

Why this matters

This bundle has high unused code — code-split or tree-shake to ship only what executes.

Source: web.dev / Lighthouse coverage

B
Page Weight Inventory
27 resources · 1.2 MB · 225 KB savings available
REVIEW
27 resources · 1.2 MB · 225 KB savings available
Warning::
Page weight 158 KB over 1MB target
Got: 1.2 MB Expected: ≤ 1 MB
Info::
~225 KB of savings available
Info::
10 third-party resources (25% of weight)
Info::
1 resources over 200KB
27 resources · 1.2 MiB · 10 third-party 158.0 KiB over 1MB target
Image 61% · 716.4 KiB
JavaScript 30% · 350.9 KiB
Font 7% · 88.1 KiB
CSS 1% · 14.7 KiB
Document 1% · 11.0 KiB
Other 0% · 937 B

~224.9 KiB of savings available

Remove unused JavaScript: 224.9 KiB
A
Third-Party Impact
25% third-party, 0 ms blocking
PASS
25% third-party, 0 ms blocking
Info::
Third-party code accounts for 25% of page weight (300.6 KiB of 1.2 MiB)
Info::
Third-party blocking time is low (0 ms)
75%
25%
First-party Third-party
A+
Text Compression
All text resources are compressed
PASS
All text resources are compressed
Info::
All text resources are compressed
All text resources are properly compressed.
A+
Font Loading
2 fonts (88 KB)
PASS
2 fonts (88 KB)
Info::
2 font(s) use font-display: swap (FOUT risk but functional)

Web fonts

2

88 KB total

Render-blocking

0

of 2

Dominant font-display

swap

Most common across fonts

Font loading timeline
Transfer FOIT (block) FOUT (swap)
0 ms 1.0 s 2.0 s 3.0 s 4.0 s 5.0 s 6.0 s 7.0 s 8.0 s FCP 3.4 s LCP 8.4 shttps://fonts.gstatic.com/s/raleway/v37/1Ptug8zYS_SKggPNyC0IT4ttDfA.woff21Ptug8zYS_SKggPNyC0IT4t... https://fonts.gstatic.com/s/raleway/v37/1Ptug8zYS_SKggPNyC0IT4ttDfA.woff2 — 42.1 KiB — 9 ms — font-display: swaphttps://www.royal.uk/themes/custom/kpp/fonts/2F00DD_0_0.woff22F00DD_0_0.woff2 https://www.royal.uk/themes/custom/kpp/fonts/2F00DD_0_0.woff2 — 46.0 KiB — 635 ms — font-display: swap
1Ptug8zYS_SKggPNyC0IT4t... woff2 swap
Size 42 KB
Load time 9 ms
Start 788 ms
Risk FOUT — text flashes from fallback to web font
2F00DD_0_0.woff2 woff2 swap
Size 46 KB
Load time 635 ms
Start 788 ms
Risk FOUT — text flashes from fallback to web font
Optimization checklist
  • Preload critical fonts (priority=high)
  • Use woff2 format for all fonts
  • Set font-display to swap, optional, or fallback
  • Subset large fonts (≤100 KB each)
A+
Resource Caching
All resources properly cached
PASS
All resources properly cached
Info::
No caching issues found
All static resources have appropriate caching headers.
A+
Critical Rendering Path
No render-blocking resources
PASS
No render-blocking resources
Info::
No render-blocking resources detected
A+
Resource Hints
No optimization needed
PASS
No optimization needed
Info::
No resource hint issues
A+
Render-Blocking Resources
No render-blocking resources detected
PASS
No render-blocking resources detected
Info::
No render-blocking resources detected in <head>
A+
Third-Party Resources
No third-party resources detected
PASS
No third-party resources detected
A+
Green Hosting
Whether the site is served from green-energy infrastructure
PASS

Green Hosting

This site is hosted on green energy infrastructure

Provider: Cloudflare

A+
HTTP Caching
max-age=86400 (1 day)
PASS
max-age=86400 (1 day)
Info::
Cache-Control header is set
Got: public, max-age=86400
Info::
Effective TTL: 1 day (max-age=86400)
Info::
Last-Modified header present
Cache-Control

public, max-age=86400

DirectiveValueMeaning
public—Any cache may store this response
max-age86400Cache for 1 day
Effective TTL: 86400 seconds
Network Waterfall
27 requests over 2093ms
INFO
0 ms 1.0 s 2.0 s 3.0 s 4.0 s 5.0 s 6.0 s 7.0 s 8.0 s FCP 3.4 s LCP 8.4 shttps://www.royal.uk// https://www.royal.uk/ — 200 — 10.2 KiB — 50 ms — h2https://consent.cookiebot.com/uc.jsconsent.cookiebot.com/uc.js https://consent.cookiebot.com/uc.js — 200 — 27.0 KiB — 45 ms — h2https://fonts.googleapis.com/css2?family=Raleway:ital,wght@0,400;0,500;0,700;1,400&display=swapfonts.googleapis.com/css2?family=Ra... https://fonts.googleapis.com/css2?family=Raleway:ital,wght@0,400;0,500;0,700;1,400&display=swap — 200 — 1.1 KiB — 100 ms — h2https://www.royal.uk/sites/default/files/css/css_jVeRHy8J-7kMKwoBTv1v-M6XK2Ms_G3oh988kWUnK_A.css?delta=0&language=en&theme=kpp&include=eJxVT1sOwzAIu1DTHGmiCUtR80BANvX2i9pt3X6QbYxsNmYPYhQyTtvA99YM5YAptwWyU9sz1XRIK0J8b6neqZLtLoDEfyUJnUomtc9pAaquYO0HY0jojOydKm0fSU9clAz1simChPWEG7EbRbaTtUDjomAkuOzW-EtuhTT4hBXl5wkGgSTAq_oonSHPlzL3yn0ZnVeMk-5qWPwCitOD8Kn-mHNpsWd8AadKdqs/sites/default/files/css/css_jVeRHy... https://www.royal.uk/sites/default/files/css/css_jVeRHy8J-7kMKwoBTv1v-M6XK2Ms_G3oh988kWUnK_A.css?delta=0&language=en&theme=kpp&include=eJxVT1sOwzAIu1DTHGmiCUtR80BANvX2i9pt3X6QbYxsNmYPYhQyTtvA99YM5YAptwWyU9sz1XRIK0J8b6neqZLtLoDEfyUJnUomtc9pAaquYO0HY0jojOydKm0fSU9clAz1simChPWEG7EbRbaTtUDjomAkuOzW-EtuhTT4hBXl5wkGgSTAq_oonSHPlzL3yn0ZnVeMk-5qWPwCitOD8Kn-mHNpsWd8AadKdqs — 200 — 4.9 KiB — 647 ms — h2https://www.royal.uk/sites/default/files/css/css_Kox2AllbaXpzyYfQhoimKnb8vXheL8psbuEUj39nETg.css?delta=1&language=en&theme=kpp&include=eJxVT1sOwzAIu1DTHGmiCUtR80BANvX2i9pt3X6QbYxsNmYPYhQyTtvA99YM5YAptwWyU9sz1XRIK0J8b6neqZLtLoDEfyUJnUomtc9pAaquYO0HY0jojOydKm0fSU9clAz1simChPWEG7EbRbaTtUDjomAkuOzW-EtuhTT4hBXl5wkGgSTAq_oonSHPlzL3yn0ZnVeMk-5qWPwCitOD8Kn-mHNpsWd8AadKdqs/sites/default/files/css/css_Kox2Al... https://www.royal.uk/sites/default/files/css/css_Kox2AllbaXpzyYfQhoimKnb8vXheL8psbuEUj39nETg.css?delta=1&language=en&theme=kpp&include=eJxVT1sOwzAIu1DTHGmiCUtR80BANvX2i9pt3X6QbYxsNmYPYhQyTtvA99YM5YAptwWyU9sz1XRIK0J8b6neqZLtLoDEfyUJnUomtc9pAaquYO0HY0jojOydKm0fSU9clAz1simChPWEG7EbRbaTtUDjomAkuOzW-EtuhTT4hBXl5wkGgSTAq_oonSHPlzL3yn0ZnVeMk-5qWPwCitOD8Kn-mHNpsWd8AadKdqs — 200 — 8.7 KiB — 632 ms — h2https://www.royal.uk/themes/custom/kpp/dist/images/crest-blue.svg/themes/custom/kpp/dist/images/cres... https://www.royal.uk/themes/custom/kpp/dist/images/crest-blue.svg — 200 — 57.4 KiB — 650 ms — h2https://www.royal.uk/sites/default/files/js/js_skslNSOfxlTUCgjg_JXTTLpJ-Pa54XwbsRG2ar-Ey_A.js?scope=footer&delta=0&language=en&theme=kpp&include=eJwdjVESgyAMRC8E5khOJKmmUsIE1NLTV_Oz8_Z97CY1BrKjYp5IMOs64Ru_Ya8VMCU1Ei3eNkZic5TykiJ9xNWE3JgOzPHipUnnFj9cDveN0dL24JxUd-FFO9yrHDL-BjwRTuGrgad__wEuBjhK/sites/default/files/js/js_skslNSOf... https://www.royal.uk/sites/default/files/js/js_skslNSOfxlTUCgjg_JXTTLpJ-Pa54XwbsRG2ar-Ey_A.js?scope=footer&delta=0&language=en&theme=kpp&include=eJwdjVESgyAMRC8E5khOJKmmUsIE1NLTV_Oz8_Z97CY1BrKjYp5IMOs64Ru_Ya8VMCU1Ei3eNkZic5TykiJ9xNWE3JgOzPHipUnnFj9cDveN0dL24JxUd-FFO9yrHDL-BjwRTuGrgad__wEuBjhK — 200 — 91.8 KiB — 1.0 s — h2https://consentcdn.cookiebot.com/consentconfig/e6cc3f6f-4a95-47e7-8b38-0232754863a7/settings.jsonconsentcdn.cookiebot.com/consentcon... https://consentcdn.cookiebot.com/consentconfig/e6cc3f6f-4a95-47e7-8b38-0232754863a7/settings.json — 200 — 937 B — 26 ms — h2https://www.googletagmanager.com/gtm.js?id=GTM-WBJ2Q8Rwww.googletagmanager.com/gtm.js?id=... https://www.googletagmanager.com/gtm.js?id=GTM-WBJ2Q8R — 200 — 119.6 KiB — 159 ms — h2https://consentcdn.cookiebot.com/consentconfig/e6cc3f6f-4a95-47e7-8b38-0232754863a7/royal.uk/configuration.jsconsentcdn.cookiebot.com/consentcon... https://consentcdn.cookiebot.com/consentconfig/e6cc3f6f-4a95-47e7-8b38-0232754863a7/royal.uk/configuration.js — 200 — 732 B — 20 ms — h2https://consent.cookiebot.com/e6cc3f6f-4a95-47e7-8b38-0232754863a7/cc.js?renew=false&referer=www.royal.uk&dnt=false&init=falseconsent.cookiebot.com/e6cc3f6f-4a95... https://consent.cookiebot.com/e6cc3f6f-4a95-47e7-8b38-0232754863a7/cc.js?renew=false&referer=www.royal.uk&dnt=false&init=false — 200 — 108.2 KiB — 332 ms — h2https://consentcdn.cookiebot.com/sdk/bc-v4.min.htmlconsentcdn.cookiebot.com/sdk/bc-v4.... https://consentcdn.cookiebot.com/sdk/bc-v4.min.html — 200 — 811 B — 11 ms — h2data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAC4AAAAuCAYAAABXuSs3AAAAAXNSR0IArs4c6QAAAARnQU1BAACxj…data:image/png;base64,iVBORw0KGgoAA... data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAC4AAAAuCAYAAABXuSs3AAAAAXNSR0IArs4c6QAAAARnQU1BAACxj… — 200 — 0 B — 0 ms — datadata:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAABIAAAASCAYAAABWzo5XAAAACXBIWXMAAAsTAAALEwEAmpwYAAAAA…data:image/png;base64,iVBORw0KGgoAA... data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAABIAAAASCAYAAABWzo5XAAAACXBIWXMAAAsTAAALEwEAmpwYAAAAA… — 200 — 0 B — 0 ms — datahttps://www.royal.uk/sites/default/files/js/js_skslNSOfxlTUCgjg_JXTTLpJ-Pa54XwbsRG2ar-Ey_A.js?scope=footer&delta=0&language=en&theme=kpp&include=eJwdjVESgyAMRC8E5khOJKmmUsIE1NLTV_Oz8_Z97CY1BrKjYp5IMOs64Ru_Ya8VMCU1Ei3eNkZic5TykiJ9xNWE3JgOzPHipUnnFj9cDveN0dL24JxUd-FFO9yrHDL-BjwRTuGrgad__wEuBjhK/sites/default/files/js/js_skslNSOf... https://www.royal.uk/sites/default/files/js/js_skslNSOfxlTUCgjg_JXTTLpJ-Pa54XwbsRG2ar-Ey_A.js?scope=footer&delta=0&language=en&theme=kpp&include=eJwdjVESgyAMRC8E5khOJKmmUsIE1NLTV_Oz8_Z97CY1BrKjYp5IMOs64Ru_Ya8VMCU1Ei3eNkZic5TykiJ9xNWE3JgOzPHipUnnFj9cDveN0dL24JxUd-FFO9yrHDL-BjwRTuGrgad__wEuBjhK — 200 — 0 B — 372 ms — h2https://www.royal.uk/themes/custom/kpp/dist/images/background.png/themes/custom/kpp/dist/images/back... https://www.royal.uk/themes/custom/kpp/dist/images/background.png — 200 — 445.9 KiB — 1.4 s — h2https://fonts.gstatic.com/s/raleway/v37/1Ptug8zYS_SKggPNyC0IT4ttDfA.woff2fonts.gstatic.com/s/raleway/v37/1Pt... https://fonts.gstatic.com/s/raleway/v37/1Ptug8zYS_SKggPNyC0IT4ttDfA.woff2 — 200 — 42.1 KiB — 9 ms — h3https://www.royal.uk/themes/custom/kpp/fonts/2F00DD_0_0.woff2/themes/custom/kpp/fonts/2F00DD_0_0... https://www.royal.uk/themes/custom/kpp/fonts/2F00DD_0_0.woff2 — 200 — 46.0 KiB — 635 ms — h2https://www.royal.uk/themes/custom/kpp/favicon.png/themes/custom/kpp/favicon.png https://www.royal.uk/themes/custom/kpp/favicon.png — 200 — 44.1 KiB — 948 ms — h2https://www.royal.uk/libraries/lazysizes/lazysizes.min.js/libraries/lazysizes/lazysizes.min.... https://www.royal.uk/libraries/lazysizes/lazysizes.min.js — 200 — 3.5 KiB — 618 ms — h2https://www.royal.uk/sites/default/files/styles/460x460/public/images/2023-04/Screenshot%202023-04-30%20at%206.17.31%20PM_0.png.webp?h=a47f98b7&itok=arw8ZwVn/sites/default/files/styles/460x460... https://www.royal.uk/sites/default/files/styles/460x460/public/images/2023-04/Screenshot%202023-04-30%20at%206.17.31%20PM_0.png.webp?h=a47f98b7&itok=arw8ZwVn — 200 — 31.7 KiB — 626 ms — h2https://www.royal.uk/sites/default/files/styles/grid_2x2/public/images/2023-04/Screenshot%202023-04-30%20at%206.47.34%20PM_0.png.webp?h=05f36d91&itok=nHEZrpJa/sites/default/files/styles/grid_2x... https://www.royal.uk/sites/default/files/styles/grid_2x2/public/images/2023-04/Screenshot%202023-04-30%20at%206.47.34%20PM_0.png.webp?h=05f36d91&itok=nHEZrpJa — 200 — 27.6 KiB — 629 ms — h2https://www.royal.uk/sites/default/files/styles/460x460/public/images/2026-04/PA-1303311.jpg.webp?h=6cff6492&itok=5QkV5ykN/sites/default/files/styles/460x460... https://www.royal.uk/sites/default/files/styles/460x460/public/images/2026-04/PA-1303311.jpg.webp?h=6cff6492&itok=5QkV5ykN — 200 — 35.4 KiB — 182 ms — h2https://www.royal.uk/sites/default/files/styles/460x460/public/images/feature/pa-6615625.jpg.webp?itok=9TelT-fH/sites/default/files/styles/460x460... https://www.royal.uk/sites/default/files/styles/460x460/public/images/feature/pa-6615625.jpg.webp?itok=9TelT-fH — 200 — 12.6 KiB — 678 ms — h2https://www.royal.uk/sites/default/files/styles/460x460/public/images/2026-04/QG_Queen_Elizabeth_LifeInStyle_QUICK_090426_09.jpg.webp?h=0867f543&itok=i7irNYK0/sites/default/files/styles/460x460... https://www.royal.uk/sites/default/files/styles/460x460/public/images/2026-04/QG_Queen_Elizabeth_LifeInStyle_QUICK_090426_09.jpg.webp?h=0867f543&itok=i7irNYK0 — 200 — 12.6 KiB — 620 ms — h2https://www.royal.uk/sites/default/files/styles/460x460/public/images/2026-04/PA-84117172.jpg.webp?h=a06bb257&itok=sjY1rsG5/sites/default/files/styles/460x460... https://www.royal.uk/sites/default/files/styles/460x460/public/images/2026-04/PA-84117172.jpg.webp?h=a06bb257&itok=sjY1rsG5 — 200 — 27.0 KiB — 703 ms — h2https://www.royal.uk/sites/default/files/styles/460x460/public/images/2026-03/PA-83939500.jpg.webp?h=1f9de911&itok=pLsOCQEv/sites/default/files/styles/460x460... https://www.royal.uk/sites/default/files/styles/460x460/public/images/2026-03/PA-83939500.jpg.webp?h=1f9de911&itok=pLsOCQEv — 200 — 22.3 KiB — 638 ms — h2
HTML JavaScript CSS Images Fonts XHR/Fetch Other
Third-Party Script Cost
Per-script blocking time, transfer cost, and cache headers
INFO
51% of JavaScript execution is third-party
First-party Third-party 1086ms · 255KB · £11/mo
Unattributable
Other
Costly
Execution 354ms
Transfer 0 KB
Monthly Cost £4/mo
consent.cookiebot.com
Other
Costly
Execution 322ms
Transfer 108 KB
Unused 24%
Monthly Cost £3/mo
consent.cookiebot.com
Other
Costly
Execution 274ms
Transfer 27 KB
Monthly Cost £3/mo
Google Tag Manager
Tag Manager
Optional
Execution 137ms
Transfer 120 KB
Unused 59%
Monthly Cost £1/mo

These scripts may cost more than they're worth

  • Unattributable adds 354ms and costs ~£4/month
  • consent.cookiebot.com adds 322ms and costs ~£3/month
  • consent.cookiebot.com adds 274ms and costs ~£3/month

51% of JavaScript execution time comes from third-party scripts.

Why this matters

Third-party scripts (analytics, ads, social, A/B testing) often dominate execution time — every one is a perf-and-privacy tax.

Learn more ▾

Each third-party script is a black box: you don't control when it loads, what it executes, or how much it grows. They often account for a major share of total blocking time on average sites (HTTP Archive's Web Almanac documents the trend). Audit which ones you actually need, defer the rest, and use facade patterns (lite-youtube, lite-vimeo) for embedded media.

Source: web.dev / HTTP Archive Web Almanac

Unattributable takes 354ms of CPU time. Consider loading it asynchronously or replacing it with a lighter alternative.

Why this matters

This script has high main-thread execution time — optimize hot paths or defer.

Source: web.dev

consent.cookiebot.com takes 322ms of CPU time. Consider loading it asynchronously or replacing it with a lighter alternative.

Why this matters

This script has high main-thread execution time — optimize hot paths or defer.

Source: web.dev

consent.cookiebot.com takes 274ms of CPU time. Consider loading it asynchronously or replacing it with a lighter alternative.

Why this matters

This script has high main-thread execution time — optimize hot paths or defer.

Source: web.dev

59% of Google Tag Manager's code is unused. The script may be loading features you don't use.

Why this matters

Bundle has high unused-code ratio — tree-shaking and route-splitting recover the wasted bytes.

Source: web.dev

How third-party costs are calculated

All checks on this page are automated. Results are estimates - run targeted manual reviews when the score affects a release decision.

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