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Performance

· 17 checks — Lighthouse + waterfall + sustainability rolled into one auditable list.
SCORE
87
GRADE
B
FIX
2
REVIEW
4
PASS
9
INFO
2

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

Mobile Desktop
62
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.
96
Best Practices Checks for modern web development best practices including HTTPS, no console errors, and secure JavaScript.
100
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.

2.10 s

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

6.33 s

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

524 ms

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

0.028

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

2.10 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.

6.33 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
9 PASS 4 REVIEW 2 FIX
D
Third-Party Impact
Action
100% third-party, 0 ms blocking
FIX
100% third-party, 0 ms blocking
Warning::
Third-party code accounts for 100% of page weight (669.6 KiB of 670.1 KiB)
Info::
Third-party blocking time is low (0 ms)
100%
First-party Third-party
F
HTTP Caching
Action
No cache headers
FIX
No cache headers
Warning::
No Cache-Control header found
Browsers will use heuristic caching, which can be unpredictable. Set explicit cache headers.

No Cache-Control header

Adding a Cache-Control header can significantly improve repeat-visit performance.

B
Image Optimization
6 images, 0 KB saveable
REVIEW
6 images, 0 KB saveable
Warning::
https://www.osti.gov/assets/content/images/DOE-SC-... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
6 images 99 KB
0 oversized -0 KB
5 legacy format
1 missing dimensions CLS risk

Set explicit width and height to prevent CLS.

Why this matters

Image without explicit width/height — browser can't reserve space; CLS jumps when image loads.

Source: web.dev / Core Web Vitals

C
JS Execution Cost
Action
1500ms total JS execution
REVIEW
1500ms total JS execution
Warning::
https://www.googletagmanager.com/gtag/js?id=G-MP0J...: 766ms CPU time
Warning::
https://www.osti.gov/: 360ms CPU time
Warning::
Unattributable: 252ms CPU time
Info::
https://www.osti.gov/assets/content/js/jquery-3.5....: 122ms CPU time
Warning::
Third-party scripts: 1500ms (100% of total)

Main Thread Breakdown

Script Evaluation 43% Other 20% Script Parsing & Compilation 16% Style & Layout 12% Parse HTML & CSS 6%
ScriptTotalScriptingParse/CompileParty
https://www.googletagmanager.com/gtag/js?id=G-MP0JFZ283F766ms506ms221ms3rd
https://www.osti.gov/360ms61ms12ms3rd
Unattributable252ms7ms0ms3rd
https://www.osti.gov/assets/content/js/jquery-3.5.1.min.js122ms68ms11ms3rd
B
JS Bundles
13 scripts, 61 KB unused
REVIEW
13 scripts, 61 KB unused
Warning::
https://www.googletagmanager.com/gtag/js?id=G-MP0J...: 61 KB unused (38%)
Consider code splitting or tree shaking to reduce unused code.
Info::
Total unused JavaScript: 61 KB
61 KB unused JavaScript

Downloaded but never executed on this page.

ScriptSizeUnusedMinifiedParty
https://www.googletagmanager.com/gtag/js?id=G-MP0JFZ283F163 KB61 KB (38%)✓3rd
https://www.osti.gov/assets/content/js/jquery-3.5.1.min.js0 KB—✓3rd
https://www.osti.gov/static/assets/content/js/jquery-3.5.1.min.js31 KB—✓3rd
https://www.osti.gov/assets/content/js/jquery-migrate.min.js?v=30 KB—✓3rd
https://www.osti.gov/assets/content/js/jquery.once.js?v=1.20 KB—✓3rd
https://www.osti.gov/assets/content/misc/drupal.js?p5yarc0 KB—✗3rd
https://www.osti.gov/assets/content/sites/all/modules/extlink/extlink.js0 KB—✓3rd
https://www.osti.gov/assets/content/sites/all/modules/ctools/js/collapsible-div.js0 KB—✓3rd
https://www.osti.gov/static/assets/content/js/jquery-migrate.min.js?v=33 KB—✓3rd
https://www.osti.gov/static/assets/content/js/jquery.once.js?v=1.22 KB—✓3rd

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

C
Green Hosting
Action
Whether the site is served from green-energy infrastructure
REVIEW

Green Hosting

No green hosting detected

A+
Page Weight Budget
670 KB transferred, 37 requests
PASS
670 KB transferred, 37 requests
Info::
Page weighs 1.6 MB (670 KB transferred)
Info::
37 HTTP requests
Info::
Estimated 0.14 g CO2 per page load
670 KB / 2.4 MB budget
670 KB transferred
37 requests
0.14 g CO2 per page load
JavaScript 211.4 KiB 32%
CSS 142.6 KiB 21%
Fonts 134.5 KiB 20%
Images 98.7 KiB 15%
HTML 53.6 KiB 8%
Other 23.1 KiB 3%
Other 5.6 KiB 1%
Other 595 B 0%
0 2.4 MB 4.9 MB
Under budget
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
3 fonts (135 KB)
PASS
3 fonts (135 KB)
Info::
3 font(s) use font-display: swap (FOUT risk but functional)

Web fonts

3

135 KB total

Render-blocking

0

of 3

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 FCP 2.1 s LCP 6.3 sdata:application/font-woff;charset=utf-8;base64,d09GRgABAAAAAX7oAA0AAAAChqwABAAHAAAAAAAAAAAAAAAAAAA…font-woff;charset=utf-8... data:application/font-woff;charset=utf-8;base64,d09GRgABAAAAAX7oAA0AAAAChqwABAAHAAAAAAAAAAAAAAAAAAA… — 95.7 KiB — 63 ms — font-display: swapdata:application/font-woff;charset=utf-8;base64,d09GRgABAAAAAE1wABIAAAAAilAAAQABAAAAAAAAAAAAAAAAAAA…font-woff;charset=utf-8... data:application/font-woff;charset=utf-8;base64,d09GRgABAAAAAE1wABIAAAAAilAAAQABAAAAAAAAAAAAAAAAAAA… — 19.4 KiB — 63 ms — font-display: swapdata:application/font-woff;charset=utf-8;base64,d09GRgABAAAAAE3MABIAAAAAiowAAQABAAAAAAAAAAAAAAAAAAA…font-woff;charset=utf-8... data:application/font-woff;charset=utf-8;base64,d09GRgABAAAAAE3MABIAAAAAiowAAQABAAAAAAAAAAAAAAAAAAA… — 19.4 KiB — 61 ms — font-display: swap
font-woff;charset=utf-8... woff swap
Size 96 KB
Load time 63 ms
Start 444 ms
Risk FOUT — text flashes from fallback to web font
  • Convert to woff2 for ~30% smaller file size
font-woff;charset=utf-8... woff swap
Size 19 KB
Load time 63 ms
Start 447 ms
Risk FOUT — text flashes from fallback to web font
  • Convert to woff2 for ~30% smaller file size
font-woff;charset=utf-8... woff swap
Size 19 KB
Load time 61 ms
Start 450 ms
Risk FOUT — text flashes from fallback to web font
  • Convert to woff2 for ~30% smaller file size
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)

Fixing the unchecked items could save ~40 KB and ~80 ms

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
1 hints, 0 missing preconnects
PASS
1 hints, 0 missing preconnects
Info::
Page uses 1 resource hint(s)

Current Resource Hints

preconnect
—
preload
1
dns-prefetch
—
prefetch
—

1 resource hints configured

A
Page Weight Inventory
37 resources · 670 KB · 61 KB savings available
PASS
37 resources · 670 KB · 61 KB savings available
Info::
Within 1MB page-weight target
Got: 670 KB
Info::
~61 KB of savings available
Warning::
36 third-party resources (100% of weight)
37 resources · 670.1 KiB · 36 third-party Within 1MB page-weight target
JavaScript 32% · 213.9 KiB
CSS 21% · 143.4 KiB
Font 20% · 134.5 KiB
Image 17% · 112.1 KiB
Document 10% · 65.5 KiB
Other 0% · 595 B

~61.4 KiB of savings available

Remove unused JavaScript: 61.4 KiB
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
Network Waterfall
37 requests over 720ms
INFO
0 ms 1.0 s 2.0 s 3.0 s 4.0 s 5.0 s 6.0 s FCP 2.1 s LCP 6.3 shttps://osti.gov// https://osti.gov/ — 301 — 481 B — 106 ms — http/1.1https://www.osti.gov/www.osti.gov/ https://www.osti.gov/ — 200 — 53.6 KiB — 144 ms — http/1.1https://www.osti.gov/loginwww.osti.gov/login https://www.osti.gov/login — 200 — 5.9 KiB — 120 ms — http/1.1https://www.osti.gov/assets/content/css/fontawesome.font_.csswww.osti.gov/assets/content/css/fon... https://www.osti.gov/assets/content/css/fontawesome.font_.css — 302 — 414 B — 49 ms — http/1.1https://www.osti.gov/assets/content/css/roboto.font_.csswww.osti.gov/assets/content/css/rob... https://www.osti.gov/assets/content/css/roboto.font_.css — 302 — 409 B — 81 ms — http/1.1https://www.googletagmanager.com/gtag/js?id=G-MP0JFZ283Fwww.googletagmanager.com/gtag/js?id... https://www.googletagmanager.com/gtag/js?id=G-MP0JFZ283F — 200 — 163.5 KiB — 73 ms — h2https://www.osti.gov/assets/content/images/doe-seal-white-600-33-min.pngwww.osti.gov/assets/content/images/... https://www.osti.gov/assets/content/images/doe-seal-white-600-33-min.png — 302 — 426 B — 108 ms — http/1.1https://www.osti.gov/assets/content/images/OSTItitle_325-min.pngwww.osti.gov/assets/content/images/... https://www.osti.gov/assets/content/images/OSTItitle_325-min.png — 302 — 418 B — 174 ms — http/1.1https://www.osti.gov/assets/content/images/DOE-SC-OSTI-RGB-Logo.docx_:user:_rId14_:msword:_media_image6.svgwww.osti.gov/assets/content/images/... https://www.osti.gov/assets/content/images/DOE-SC-OSTI-RGB-Logo.docx_:user:_rId14_:msword:_media_image6.svg — 302 — 432 B — 178 ms — http/1.1https://www.osti.gov/assets/content/js/jquery-3.5.1.min.jswww.osti.gov/assets/content/js/jque... https://www.osti.gov/assets/content/js/jquery-3.5.1.min.js — 302 — 426 B — 106 ms — http/1.1https://www.osti.gov/static/assets/content/css/fontawesome.font_.csswww.osti.gov/static/assets/content/... https://www.osti.gov/static/assets/content/css/fontawesome.font_.css — 200 — 105.3 KiB — 108 ms — http/1.1https://www.osti.gov/static/assets/content/css/roboto.font_.csswww.osti.gov/static/assets/content/... https://www.osti.gov/static/assets/content/css/roboto.font_.css — 200 — 37.3 KiB — 62 ms — http/1.1https://www.osti.gov/static/assets/content/images/doe-seal-white-600-33-min.pngwww.osti.gov/static/assets/content/... https://www.osti.gov/static/assets/content/images/doe-seal-white-600-33-min.png — 200 — 9.0 KiB — 29 ms — http/1.1https://www.osti.gov/static/assets/content/js/jquery-3.5.1.min.jswww.osti.gov/static/assets/content/... https://www.osti.gov/static/assets/content/js/jquery-3.5.1.min.js — 200 — 30.7 KiB — 58 ms — http/1.1https://www.osti.gov/assets/content/js/jquery-migrate.min.js?v=3www.osti.gov/assets/content/js/jque... https://www.osti.gov/assets/content/js/jquery-migrate.min.js?v=3 — 302 — 431 B — 97 ms — http/1.1https://www.osti.gov/assets/content/js/jquery.once.js?v=1.2www.osti.gov/assets/content/js/jque... https://www.osti.gov/assets/content/js/jquery.once.js?v=1.2 — 302 — 426 B — 83 ms — http/1.1https://www.osti.gov/assets/content/misc/drupal.js?p5yarcwww.osti.gov/assets/content/misc/dr... https://www.osti.gov/assets/content/misc/drupal.js?p5yarc — 302 — 424 B — 101 ms — http/1.1https://www.google-analytics.com/g/collect?v=2&tid=G-MP0JFZ283F&gtm=45je64k1h2v9116238154za200zd9116238154&_p=1776896020755&gcd=13l3l3l3l1l1&npa=0&dma=0&are=1&cid=1113934978.1776896021&frm=0&pscdl=noapi&rcb=2&sr=412x823&uaa=&uab=64&uafvl=Not-A.Brand%3B24.0.0.0%7CChromium%3B146.0.7680.164&uam=moto%20g%20power%20(2022)&uamb=1&uap=Android&uapv=11.0&uaw=0&ul=en-us&_s=1&tag_exp=0~115938465~115938469~117266400~117512542&sid=1776896020&sct=1&seg=0&dl=https%3A%2F%2Fwww.osti.gov%2F&dt=OSTI.GOV%20%7C%20U.S.%20Department%20of%20Energy%20Office%20of%20Scientific%20and%20Technical%20Information&en=page_view&_fv=1&_nsi=1&_ss=1&_ee=1&tfd=428www.google-analytics.com/g/collect?... https://www.google-analytics.com/g/collect?v=2&tid=G-MP0JFZ283F&gtm=45je64k1h2v9116238154za200zd9116238154&_p=1776896020755&gcd=13l3l3l3l1l1&npa=0&dma=0&are=1&cid=1113934978.1776896021&frm=0&pscdl=noapi&rcb=2&sr=412x823&uaa=&uab=64&uafvl=Not-A.Brand%3B24.0.0.0%7CChromium%3B146.0.7680.164&uam=moto%20g%20power%20(2022)&uamb=1&uap=Android&uapv=11.0&uaw=0&ul=en-us&_s=1&tag_exp=0~115938465~115938469~117266400~117512542&sid=1776896020&sct=1&seg=0&dl=https%3A%2F%2Fwww.osti.gov%2F&dt=OSTI.GOV%20%7C%20U.S.%20Department%20of%20Energy%20Office%20of%20Scientific%20and%20Technical%20Information&en=page_view&_fv=1&_nsi=1&_ss=1&_ee=1&tfd=428 — 204 — 547 B — 95 ms — h2https://www.osti.gov/assets/content/sites/all/modules/extlink/extlink.jswww.osti.gov/assets/content/sites/a... https://www.osti.gov/assets/content/sites/all/modules/extlink/extlink.js — 302 — 439 B — 84 ms — http/1.1https://www.google-analytics.com/g/collect?v=2&tid=G-4W8DTEJH5Q&gtm=45je64k1h2v9116238154za200zd9116238154&_p=1776896020755&gcd=13l3l3l3l1l1&npa=0&dma=0&are=1&cid=1113934978.1776896021&frm=0&pscdl=noapi&rcb=2&sr=412x823&uaa=&uab=64&uafvl=Not-A.Brand%3B24.0.0.0%7CChromium%3B146.0.7680.164&uam=moto%20g%20power%20(2022)&uamb=1&uap=Android&uapv=11.0&uaw=0&ul=en-us&_s=1&tag_exp=0~115938465~115938469~117266400~117512542&sid=1776896020&sct=1&seg=0&dl=https%3A%2F%2Fwww.osti.gov%2F&dt=OSTI.GOV%20%7C%20U.S.%20Department%20of%20Energy%20Office%20of%20Scientific%20and%20Technical%20Information&en=page_view&_fv=1&_ss=1&_ee=1&tfd=435www.google-analytics.com/g/collect?... https://www.google-analytics.com/g/collect?v=2&tid=G-4W8DTEJH5Q&gtm=45je64k1h2v9116238154za200zd9116238154&_p=1776896020755&gcd=13l3l3l3l1l1&npa=0&dma=0&are=1&cid=1113934978.1776896021&frm=0&pscdl=noapi&rcb=2&sr=412x823&uaa=&uab=64&uafvl=Not-A.Brand%3B24.0.0.0%7CChromium%3B146.0.7680.164&uam=moto%20g%20power%20(2022)&uamb=1&uap=Android&uapv=11.0&uaw=0&ul=en-us&_s=1&tag_exp=0~115938465~115938469~117266400~117512542&sid=1776896020&sct=1&seg=0&dl=https%3A%2F%2Fwww.osti.gov%2F&dt=OSTI.GOV%20%7C%20U.S.%20Department%20of%20Energy%20Office%20of%20Scientific%20and%20Technical%20Information&en=page_view&_fv=1&_ss=1&_ee=1&tfd=435 — 204 — 48 B — 90 ms — h2https://www.osti.gov/static/assets/content/images/OSTItitle_325-min.pngwww.osti.gov/static/assets/content/... https://www.osti.gov/static/assets/content/images/OSTItitle_325-min.png — 200 — 2.3 KiB — 31 ms — http/1.1https://www.osti.gov/static/assets/content/images/DOE-SC-OSTI-RGB-Logo.docx_:user:_rId14_:msword:_media_image6.svgwww.osti.gov/static/assets/content/... https://www.osti.gov/static/assets/content/images/DOE-SC-OSTI-RGB-Logo.docx_:user:_rId14_:msword:_media_image6.svg — 200 — 50.2 KiB — 50 ms — http/1.1data:application/font-woff;charset=utf-8;base64,d09GRgABAAAAAX7oAA0AAAAChqwABAAHAAAAAAAAAAAAAAAAAAA…data:application/font-woff;charset=... data:application/font-woff;charset=utf-8;base64,d09GRgABAAAAAX7oAA0AAAAChqwABAAHAAAAAAAAAAAAAAAAAAA… — 200 — 95.7 KiB — 63 ms — datadata:application/font-woff;charset=utf-8;base64,d09GRgABAAAAAE1wABIAAAAAilAAAQABAAAAAAAAAAAAAAAAAAA…data:application/font-woff;charset=... data:application/font-woff;charset=utf-8;base64,d09GRgABAAAAAE1wABIAAAAAilAAAQABAAAAAAAAAAAAAAAAAAA… — 200 — 19.4 KiB — 63 ms — datadata:application/font-woff;charset=utf-8;base64,d09GRgABAAAAAE3MABIAAAAAiowAAQABAAAAAAAAAAAAAAAAAAA…data:application/font-woff;charset=... data:application/font-woff;charset=utf-8;base64,d09GRgABAAAAAE3MABIAAAAAiowAAQABAAAAAAAAAAAAAAAAAAA… — 200 — 19.4 KiB — 61 ms — datahttps://www.osti.gov/assets/content/sites/all/modules/ctools/js/collapsible-div.jswww.osti.gov/assets/content/sites/a... https://www.osti.gov/assets/content/sites/all/modules/ctools/js/collapsible-div.js — 302 — 449 B — 55 ms — http/1.1https://www.osti.gov/static/assets/content/js/jquery-migrate.min.js?v=3www.osti.gov/static/assets/content/... https://www.osti.gov/static/assets/content/js/jquery-migrate.min.js?v=3 — 200 — 3.1 KiB — 32 ms — http/1.1https://www.osti.gov/static/assets/content/js/jquery.once.js?v=1.2www.osti.gov/static/assets/content/... https://www.osti.gov/static/assets/content/js/jquery.once.js?v=1.2 — 200 — 1.5 KiB — 31 ms — http/1.1https://www.osti.gov/static/assets/content/misc/drupal.js?p5yarcwww.osti.gov/static/assets/content/... https://www.osti.gov/static/assets/content/misc/drupal.js?p5yarc — 200 — 7.4 KiB — 32 ms — http/1.1https://www.osti.gov/static/assets/content/sites/all/modules/extlink/extlink.jswww.osti.gov/static/assets/content/... https://www.osti.gov/static/assets/content/sites/all/modules/extlink/extlink.js — 200 — 2.4 KiB — 28 ms — http/1.1
0 ms 1.0 s 2.0 s 3.0 s 4.0 s 5.0 s 6.0 s FCP 2.1 s LCP 6.3 shttps://osti.gov// https://osti.gov/ — 301 — 481 B — 106 ms — http/1.1https://www.osti.gov/www.osti.gov/ https://www.osti.gov/ — 200 — 53.6 KiB — 144 ms — http/1.1https://www.osti.gov/loginwww.osti.gov/login https://www.osti.gov/login — 200 — 5.9 KiB — 120 ms — http/1.1https://www.osti.gov/assets/content/css/fontawesome.font_.csswww.osti.gov/assets/content/css/fon... https://www.osti.gov/assets/content/css/fontawesome.font_.css — 302 — 414 B — 49 ms — http/1.1https://www.osti.gov/assets/content/css/roboto.font_.csswww.osti.gov/assets/content/css/rob... https://www.osti.gov/assets/content/css/roboto.font_.css — 302 — 409 B — 81 ms — http/1.1https://www.googletagmanager.com/gtag/js?id=G-MP0JFZ283Fwww.googletagmanager.com/gtag/js?id... https://www.googletagmanager.com/gtag/js?id=G-MP0JFZ283F — 200 — 163.5 KiB — 73 ms — h2https://www.osti.gov/assets/content/images/doe-seal-white-600-33-min.pngwww.osti.gov/assets/content/images/... 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http/1.1https://www.osti.gov/static/assets/content/css/roboto.font_.csswww.osti.gov/static/assets/content/... https://www.osti.gov/static/assets/content/css/roboto.font_.css — 200 — 37.3 KiB — 62 ms — http/1.1https://www.osti.gov/static/assets/content/images/doe-seal-white-600-33-min.pngwww.osti.gov/static/assets/content/... https://www.osti.gov/static/assets/content/images/doe-seal-white-600-33-min.png — 200 — 9.0 KiB — 29 ms — http/1.1https://www.osti.gov/static/assets/content/js/jquery-3.5.1.min.jswww.osti.gov/static/assets/content/... https://www.osti.gov/static/assets/content/js/jquery-3.5.1.min.js — 200 — 30.7 KiB — 58 ms — http/1.1https://www.osti.gov/assets/content/js/jquery-migrate.min.js?v=3www.osti.gov/assets/content/js/jque... https://www.osti.gov/assets/content/js/jquery-migrate.min.js?v=3 — 302 — 431 B — 97 ms — http/1.1https://www.osti.gov/assets/content/js/jquery.once.js?v=1.2www.osti.gov/assets/content/js/jque... 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HTML JavaScript CSS Images Fonts XHR/Fetch Other
Third-Party Script Cost
Per-script blocking time, transfer cost, and cache headers
INFO
100% of JavaScript execution is third-party
First-party Third-party 1500ms · 217KB · $20/mo
Google Tag Manager
Tag Manager
Costly
Execution 766ms
Transfer 163 KB
Unused 38%
Monthly Cost $10/mo
www.osti.gov
Other
Costly
Execution 360ms
Transfer 54 KB
Monthly Cost $5/mo
Unattributable
Other
Costly
Execution 252ms
Transfer 0 KB
Monthly Cost $3/mo
www.osti.gov
Other
Optional
Execution 122ms
Transfer 0 KB
Monthly Cost $2/mo

These scripts may cost more than they're worth

  • Google Tag Manager adds 766ms and costs ~$10/month
  • www.osti.gov adds 360ms and costs ~$5/month
  • Unattributable adds 252ms and costs ~$3/month

100% of JavaScript execution time is spent on third-party scripts. Consider auditing which scripts are essential.

Why this matters

When third-party JS execution time exceeds your own, performance gains from frontend work are capped by code you don't own.

Learn more ▾

Every millisecond of third-party JS competes with your own for main-thread time. If their share is bigger than yours, optimization on your code base barely moves the needle. Audit, defer, or remove third-parties before further frontend optimization. Use Lighthouse's third-party audit to identify the worst offenders.

Source: web.dev

Google Tag Manager takes 766ms 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

www.osti.gov takes 360ms 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

Unattributable takes 252ms 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

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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