Performance

· 17 checks — Lighthouse + waterfall + sustainability rolled into one auditable list.

SCORE

GRADE

FIX

REVIEW

PASS

INFO

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

Mobile Desktop

Performance

Accessibility

Best Practices

100

SEO

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

7.67 s

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

33.06 s

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

1.79 s

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

0.001

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

8.03 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.

37.23 s

Page Load Progression

407 ms

814 ms

1.2 s

1.6 s

2.0 s

2.4 s

2.8 s

3.3 s

Checks

8 PASS 2 REVIEW 5 FIX

Page Weight Budget

Action

5.1 MB transferred, 129 requests

FIX

5.1 MB transferred, 129 requests

Page weighs 7.6 MB (5.1 MB transferred)

Images are 2.9 MB — compress or use modern formats

Convert images to WebP/AVIF and resize to display dimensions to reduce transfer size.

Got: 2.9 MB

JavaScript is 1.7 MB — consider code splitting or lazy loading

Large JavaScript bundles delay interactivity. Split code by route or defer non-critical scripts.

Got: 1.7 MB

CSS is 228 KB — consider purging unused styles

Remove unused CSS rules with tools like PurgeCSS to reduce stylesheet size.

Got: 228 KB

Fonts are 204 KB — consider subsetting or using system fonts

Subset fonts to include only used characters, or switch to system font stacks.

Got: 204 KB

129 HTTP requests — consider bundling or reducing

Each request adds latency. Bundle small files, use sprites, or eliminate unnecessary requests.

Estimated 1.1 g CO2 per page load

5.1 MB transferred

129 requests

1.1 g CO2 per page load

Images 2.9 MiB 57%

JavaScript 1.7 MiB 33%

CSS 228.1 KiB 4%

Fonts 204.2 KiB 4%

HTML 81.7 KiB 2%

Other 8.0 KiB 0%

Other 6.5 KiB 0%

Other 2.3 KiB 0%

Other 318 B 0%

Other 0 B 0%

0 2.4 MB 4.9 MB

Over budget

Convert images to WebP/AVIF and resize to display dimensions to reduce transfer size.

Why this matters

Image bandwidth is high — modern formats (WebP/AVIF) and resizing typically cut it 50%+.

Source: web.dev

Large JavaScript bundles delay interactivity. Split code by route or defer non-critical scripts.

Why this matters

JavaScript bundle is large — code-split routes and lazy-load off-screen components to defer.

Source: web.dev

Remove unused CSS rules with tools like PurgeCSS to reduce stylesheet size.

Why this matters

CSS bundle is large — purge unused styles (PurgeCSS, Tailwind JIT) to reduce CSS payload.

Source: web.dev

Subset fonts to include only used characters, or switch to system font stacks.

Why this matters

Font payload is large — subset to used glyphs only, or fall back to system fonts (zero load time).

Source: web.dev font loading

Each request adds latency. Bundle small files, use sprites, or eliminate unnecessary requests.

Why this matters

High HTTP request count — bundling, sprite-ing, and HTTP/2 server push can reduce per-request overhead.

Source: web.dev

Third-Party Impact

Action

100% third-party, 0 ms blocking

FIX

100% third-party, 0 ms blocking

Third-party code accounts for 100% of page weight (5.1 MiB of 5.1 MiB)

Third-party blocking time is low (0 ms)

100%

First-party Third-party

JS Execution Cost

Action

6254ms total JS execution

FIX

6254ms total JS execution

Unattributable: 781ms CPU time

https://www.googletagmanager.com/gtm.js?id=GTM-KQ6...: 775ms CPU time

https://www.washington.edu/: 717ms CPU time

https://www.googletagmanager.com/gtag/js?id=AW-166...: 505ms CPU time

https://script.crazyegg.com/pages/versioned/common...: 411ms CPU time

Third-party scripts: 6254ms (100% of total)

Main Thread Breakdown

Script Evaluation 61% Other 16% Script Parsing & Compilation 10% Style & Layout 8%

Script	Total	Scripting	Parse/Compile	Party
Unattributable	781ms	41ms	0ms	3rd
https://www.googletagmanager.com/gtm.js?id=GTM-KQ6QQBT	775ms	657ms	81ms	3rd
https://www.washington.edu/	717ms	11ms	3ms	3rd
https://www.googletagmanager.com/gtag/js?id=AW-16646132057&cx=c&gtm=4e64f0&bs=ctrl2	505ms	379ms	71ms	3rd
https://script.crazyegg.com/pages/versioned/common-scripts/4ce8c7df8d425cc50464576824ed91eb.js	411ms	362ms	28ms	3rd
https://www.googletagmanager.com/gtag/js?id=G-JLHM9WH4JV&cx=c&gtm=4e64f0&bs=ctrl2	397ms	321ms	73ms	3rd
https://www.googletagmanager.com/gtag/js?id=G-3T65WK0BM8&cx=c&gtm=4e64f0&bs=ctrl2	347ms	280ms	64ms	3rd
https://www.washington.edu/static/home/wp-content/themes/uw-2014/js/site.js?ver=3.1	338ms	251ms	21ms	3rd
https://info.discoveruw.org/mtc.js	318ms	223ms	2ms	3rd
https://www.googletagmanager.com/gtag/js?id=AW-11078980387&cx=c&gtm=4e64f0&bs=ctrl2	317ms	259ms	54ms	3rd

Showing top 10 of 18 scripts

JS Bundles

Action

38 scripts, 631 KB unused

FIX

38 scripts, 631 KB unused

https://www.washington.edu/static/home/wp-content/...: 113 KB unused (69%)

Consider code splitting or tree shaking to reduce unused code.

https://www.washington.edu/static/home/wp-includes...: 95 KB unused (34%)

Consider code splitting or tree shaking to reduce unused code.

https://www.washington.edu/static/home/wp-includes...: unminified — 142 KB could be saved

https://www.googletagmanager.com/gtag/js?id=G-JLHM...: 70 KB unused (40%)

Consider code splitting or tree shaking to reduce unused code.

https://www.googletagmanager.com/gtag/js?id=G-3T65...: 66 KB unused (42%)

Consider code splitting or tree shaking to reduce unused code.

https://www.googletagmanager.com/gtm.js?id=GTM-KQ6...: 61 KB unused (36%)

Consider code splitting or tree shaking to reduce unused code.

Total unused JavaScript: 631 KB

631 KB unused JavaScript

Downloaded but never executed on this page.

Script	Size	Unused	Minified	Party
https://www.washington.edu/static/home/wp-content/themes/uw-2014/js/site.js?ver=3.1	164 KB	113 KB (69%)	✓	3rd
https://www.washington.edu/static/home/wp-includes/js/jquery/jquery.js?9583878	279 KB	95 KB (34%)	✗	3rd
https://www.googletagmanager.com/gtag/js?id=G-JLHM9WH4JV&cx=c&gtm=4e64f0&bs=ctrl2	175 KB	70 KB (40%)	✓	3rd
https://www.googletagmanager.com/gtag/js?id=G-3T65WK0BM8&cx=c&gtm=4e64f0&bs=ctrl2	157 KB	66 KB (42%)	✓	3rd
https://www.googletagmanager.com/gtm.js?id=GTM-KQ6QQBT	169 KB	61 KB (36%)	✓	3rd
https://www.googletagmanager.com/gtag/js?id=DC-4532109&cx=c&gtm=4e64f0&bs=ctrl2	129 KB	57 KB (44%)	✓	3rd
https://www.googletagmanager.com/gtag/js?id=AW-11078980387&cx=c&gtm=4e64f0&bs=ctrl2	140 KB	55 KB (40%)	✓	3rd
https://www.googletagmanager.com/gtag/js?id=AW-16646132057&cx=c&gtm=4e64f0&bs=ctrl2	148 KB	52 KB (35%)	✓	3rd
https://connect.facebook.net/en_US/fbevents.js	96 KB	33 KB (34%)	✓	3rd
https://script.crazyegg.com/pages/versioned/common-scripts/4ce8c7df8d425cc50464576824ed91eb.js	55 KB	29 KB (53%)	✓	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

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

Page Weight Inventory

Action

129 resources · 5.1 MB · 631 KB savings available

FIX

129 resources · 5.1 MB · 631 KB savings available

Page weight 4.1 MB over 1MB target

Got: 5.1 MB Expected: ≤ 1 MB

~631 KB of savings available

128 third-party resources (100% of weight)

5 resources over 200KB

129 resources · 5.1 MiB · 128 third-party 4.1 MiB over 1MB target

Image 57% · 2.9 MiB

JavaScript 33% · 1.7 MiB

CSS 4% · 228.1 KiB

Font 4% · 204.2 KiB

Document 2% · 81.8 KiB

Other 0% · 15.6 KiB

~631.4 KiB of savings available

Remove unused JavaScript: 631.4 KiB

#	Resource	Type	Size	Cache	Unused	3rd party	Issues

129 resources			5.1 MiB

Image Optimization

Action

35 images, 0 KB saveable

REVIEW

35 images, 0 KB saveable

https://uw-s3-cdn.s3.us-west-2.amazonaws.com/wp-co... is missing width/height — may cause layout shift

Set explicit width and height to prevent CLS.

https://uw-s3-cdn.s3.us-west-2.amazonaws.com/wp-co... is missing width/height — may cause layout shift

Set explicit width and height to prevent CLS.

35 images 2.9 MB

0 oversized -0 KB

35 legacy format

2 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

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

HTTP Caching

no-cache

REVIEW

no-cache

Cache-Control header is set

Got: no-cache

No ETag or Last-Modified header

Conditional requests (304 Not Modified) are not possible without validators.

Cache-Control

no-cache

Directive	Value	Meaning
no-cache	—	Cache but always revalidate first

A+

Text Compression

All text resources are compressed

PASS

All text resources are compressed

All text resources are properly compressed.

A+

Font Loading

6 fonts (204 KB)

PASS

6 fonts (204 KB)

6 font(s) use font-display: swap (FOUT risk but functional)

Web fonts

204 KB total

Render-blocking

of 6

Dominant font-display

swap

Most common across fonts

Font loading timeline

Transfer FOIT (block) FOUT (swap)

encodesanscondensed-400... woff swap

Size 34 KB

Load time 208 ms

Start 2.2 s

Risk FOUT — text flashes from fallback to web font

Convert to woff2 for ~30% smaller file size

encodesanscompressed-80... woff swap

Size 32 KB

Load time 200 ms

Start 2.2 s

Risk FOUT — text flashes from fallback to web font

Convert to woff2 for ~30% smaller file size

memvYaGs126MiZpBA-UvWbX... woff2 swap

Size 42 KB

Load time 6 ms

Start 2.2 s

Risk FOUT — text flashes from fallback to web font

encodesanscompressed-60... woff swap

Size 33 KB

Load time 224 ms

Start 2.2 s

Risk FOUT — text flashes from fallback to web font

Convert to woff2 for ~30% smaller file size

encodesanscompressed-90... woff swap

Size 31 KB

Load time 216 ms

Start 2.2 s

Risk FOUT — text flashes from fallback to web font

Convert to woff2 for ~30% smaller file size

encodesanscompressed-70... woff swap

Size 32 KB

Load time 223 ms

Start 2.2 s

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 ~49 KB and ~98 ms

A+

Resource Caching

All resources properly cached

PASS

All resources properly cached

No caching issues found

All static resources have appropriate caching headers.

A+

Critical Rendering Path

No render-blocking resources

PASS

No render-blocking resources

No render-blocking resources detected

A+

Resource Hints

2 hints, 0 missing preconnects

PASS

2 hints, 0 missing preconnects

Page uses 2 resource hint(s)

Current Resource Hints

preconnect

—

preload

—

dns-prefetch

prefetch

—

2 resource hints configured

A+

Render-Blocking Resources

No render-blocking resources detected

PASS

No render-blocking resources detected

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: Google Cloud

Network Waterfall

129 requests over 8103ms

INFO

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 6254ms · 1693KB · $83/mo

Script	Category	Execution	Transfer	Unused	Monthly Cost	Verdict
Unattributable Unattributable	Other	781ms	0 KB	—	$10/mo	Costly
Google Tag Manager www.googletagmanager.com	Tag Manager	775ms	169 KB	36%	$10/mo	Costly
www.washington.edu www.washington.edu	Other	717ms	80 KB	—	$10/mo	Costly
Google Tag Manager www.googletagmanager.com	Tag Manager	505ms	148 KB	35%	$7/mo	Costly
script.crazyegg.com script.crazyegg.com	Other	411ms	55 KB	53%	$5/mo	Costly
Google Tag Manager www.googletagmanager.com	Tag Manager	397ms	175 KB	40%	$5/mo	Costly
Google Tag Manager www.googletagmanager.com	Tag Manager	347ms	157 KB	42%	$5/mo	Costly
www.washington.edu www.washington.edu	Other	338ms	164 KB	69%	$4/mo	Costly
info.discoveruw.org info.discoveruw.org	Other	318ms	4 KB	—	$4/mo	Costly
Google Tag Manager www.googletagmanager.com	Tag Manager	317ms	140 KB	40%	$4/mo	Costly
www.washington.edu www.washington.edu	Other	287ms	279 KB	34%	$4/mo	Costly
Google Tag Manager www.googletagmanager.com	Tag Manager	238ms	129 KB	44%	$3/mo	Costly
Microsoft Clarity scripts.clarity.ms	Session Replay	216ms	26 KB	—	$3/mo	Costly
Facebook Pixel connect.facebook.net	Advertising	206ms	96 KB	34%	$3/mo	Costly
Facebook Pixel connect.facebook.net	Advertising	180ms	46 KB	—	$2/mo	Optional
nexus.ensighten.com nexus.ensighten.com	Other	105ms	1 KB	—	$1/mo	Optional
LinkedIn Insight snap.licdn.com	Advertising	59ms	19 KB	—	$1/mo	Optional
up.pixel.ad up.pixel.ad	Other	57ms	3 KB	—	$1/mo	Optional

Unattributable

Other

Costly

Execution 781ms

Transfer 0 KB

Monthly Cost $10/mo

Google Tag Manager

Tag Manager

Costly

Execution 775ms

Transfer 169 KB

Unused 36%

Monthly Cost $10/mo

www.washington.edu

Other

Costly

Execution 717ms

Transfer 80 KB

Monthly Cost $10/mo

Google Tag Manager

Tag Manager

Costly

Execution 505ms

Transfer 148 KB

Unused 35%

Monthly Cost $7/mo

script.crazyegg.com

Other

Costly

Execution 411ms

Transfer 55 KB

Unused 53%

Monthly Cost $5/mo

Google Tag Manager

Tag Manager

Costly

Execution 397ms

Transfer 175 KB

Unused 40%

Monthly Cost $5/mo

Google Tag Manager

Tag Manager

Costly

Execution 347ms

Transfer 157 KB

Unused 42%

Monthly Cost $5/mo

www.washington.edu

Other

Costly

Execution 338ms

Transfer 164 KB

Unused 69%

Monthly Cost $4/mo

info.discoveruw.org

Other

Costly

Execution 318ms

Transfer 4 KB

Monthly Cost $4/mo

Google Tag Manager

Tag Manager

Costly

Execution 317ms

Transfer 140 KB

Unused 40%

Monthly Cost $4/mo

www.washington.edu

Other

Costly

Execution 287ms

Transfer 279 KB

Unused 34%

Monthly Cost $4/mo

Google Tag Manager

Tag Manager

Costly

Execution 238ms

Transfer 129 KB

Unused 44%

Monthly Cost $3/mo

Microsoft Clarity

Session Replay

Costly

Execution 216ms

Transfer 26 KB

Monthly Cost $3/mo

Facebook Pixel

Advertising

Costly

Execution 206ms

Transfer 96 KB

Unused 34%

Monthly Cost $3/mo

Facebook Pixel

Advertising

Optional

Execution 180ms

Transfer 46 KB

Monthly Cost $2/mo

nexus.ensighten.com

Other

Optional

Execution 105ms

Transfer 1 KB

Monthly Cost $1/mo

LinkedIn Insight

Advertising

Optional

Execution 59ms

Transfer 19 KB

Monthly Cost $1/mo

up.pixel.ad

Other

Optional

Execution 57ms

Transfer 3 KB

Monthly Cost $1/mo

These scripts may cost more than they're worth

Unattributable adds 781ms and costs ~$10/month
Google Tag Manager adds 775ms and costs ~$10/month
www.washington.edu adds 717ms and costs ~$10/month
Google Tag Manager adds 505ms and costs ~$7/month
script.crazyegg.com adds 411ms and costs ~$5/month
Google Tag Manager adds 397ms and costs ~$5/month
Google Tag Manager adds 347ms and costs ~$5/month
www.washington.edu adds 338ms and costs ~$4/month
info.discoveruw.org adds 318ms and costs ~$4/month
Google Tag Manager adds 317ms and costs ~$4/month
www.washington.edu adds 287ms and costs ~$4/month
Google Tag Manager adds 238ms and costs ~$3/month
Microsoft Clarity adds 216ms and costs ~$3/month
Facebook Pixel adds 206ms 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

Unattributable takes 781ms 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

Google Tag Manager takes 775ms 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.washington.edu takes 717ms 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

Google Tag Manager takes 505ms 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

script.crazyegg.com takes 411ms 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

53% of script.crazyegg.com'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

Google Tag Manager takes 397ms 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

Google Tag Manager takes 347ms 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.washington.edu takes 338ms 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

69% of www.washington.edu'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

info.discoveruw.org takes 318ms 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

Google Tag Manager takes 317ms 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.washington.edu takes 287ms 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

Google Tag Manager takes 238ms 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

Microsoft Clarity takes 216ms 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

Facebook Pixel takes 206ms 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.