Performance
· 17 checks — Lighthouse + waterfall + sustainability rolled into one auditable list.Performance-focused optimization plan with CWV assessment, top offenders, and time estimates
First Contentful Paint First Contentful Paint — how long until the browser renders the first piece of content. Under 1.8s is good.
3.01 s
Largest Contentful Paint Largest Contentful Paint — how long until the largest visible element loads. Under 2.5s is good.
9.78 s
Total Blocking Time Total Blocking Time — total time the main thread was blocked, preventing user input. Under 200ms is good.
436 ms
Cumulative Layout Shift Cumulative Layout Shift — measures visual stability. How much the page layout shifts during loading. Under 0.1 is good.
0.020
Speed Index Speed Index — how quickly content is visually displayed during load. Under 3.4s is good.
7.31 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.
11.98 s
Page Load Progression
FPage Weight BudgetAction9.0 MB transferred, 109 requestsFIX
Convert images to WebP/AVIF and resize to display dimensions to reduce transfer size.
Image bandwidth is high — modern formats (WebP/AVIF) and resizing typically cut it 50%+.
Source: web.dev
Subset fonts to include only used characters, or switch to system font stacks.
Font payload is large — subset to used glyphs only, or fall back to system fonts (zero load time).
Source: web.dev font loading
Large JavaScript bundles delay interactivity. Split code by route or defer non-critical scripts.
JavaScript bundle is large — code-split routes and lazy-load off-screen components to defer.
Source: web.dev
Each request adds latency. Bundle small files, use sprites, or eliminate unnecessary requests.
High HTTP request count — bundling, sprite-ing, and HTTP/2 server push can reduce per-request overhead.
Source: web.dev
DThird-Party ImpactAction70% third-party, 0 ms blockingFIX
DJS Execution CostAction2829ms total JS executionFIX
Main Thread Breakdown
| Script | Total | Scripting | Parse/Compile | Party |
|---|---|---|---|---|
| https://www.virginia.edu/ | 749ms | 47ms | 3ms | 1st |
| Unattributable | 655ms | 18ms | 0ms | 3rd |
| https://www.googletagmanager.com/gtm.js?id=GTM-58VK8DX | 409ms | 343ms | 49ms | 3rd |
| https://script.crazyegg.com/pages/versioned/common-scripts/4ce8c7df8d425cc50464576824ed91eb.js | 366ms | 330ms | 12ms | 3rd |
| https://ajax.googleapis.com/ajax/libs/jquery/3.7.1/jquery.min.js | 320ms | 218ms | 8ms | 3rd |
| https://www.googletagmanager.com/gtag/js?id=G-J44315NZPS&cx=c>m=4e64h1 | 221ms | 171ms | 47ms | 3rd |
| https://cdn.parsely.com/keys/virginia.edu/p.js | 108ms | 100ms | 3ms | 3rd |
DPage Weight InventoryAction109 resources · 9.0 MB · 170 KB savings availableFIX
~169.7 KiB of savings available
| # | Resource | Type | Size | Cache | Unused | 3rd party | Issues |
|---|---|---|---|---|---|---|---|
| — | — | ||||||
| 109 resources | 9.0 MiB | ||||||
FHTTP CachingActionNo cache headersFIX
No Cache-Control header
Adding a Cache-Control header can significantly improve repeat-visit performance.
CImage OptimizationAction31 images, 0 KB saveableREVIEW
Set explicit width and height to prevent CLS.
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.
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.
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.
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.
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.
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.
Performance issues directly impact user engagement and conversion rates.
Set explicit width and height to prevent CLS.
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.
Image without explicit width/height — browser can't reserve space; CLS jumps when image loads.
Source: web.dev / Core Web Vitals
CJS BundlesAction23 scripts, 170 KB unusedREVIEW
Downloaded but never executed on this page.
| Script | Size | Unused | Minified | Party |
|---|---|---|---|---|
| https://www.googletagmanager.com/gtag/js?id=G-J44315NZPS&cx=c>m=4e64h1 | 170 KB | 69 KB (40%) | ✓ | 3rd |
| https://www.googletagmanager.com/gtm.js?id=GTM-58VK8DX | 150 KB | 48 KB (32%) | ✓ | 3rd |
| https://script.crazyegg.com/pages/versioned/common-scripts/4ce8c7df8d425cc50464576824ed91eb.js | 55 KB | 27 KB (50%) | ✓ | 3rd |
| https://customer.cludo.com/scripts/bundles/search-script.min.js | 51 KB | 26 KB (52%) | ✓ | 3rd |
| https://cdn.jsdelivr.net/npm/slick-carousel@1.8.1/slick/slick.min.js | 11 KB | — | ✓ | 3rd |
| https://script.crazyegg.com/pages/scripts/0090/5137.js | 3 KB | — | ✓ | 3rd |
| https://www.virginia.edu/assets/js/calendar-feed.js | 1 KB | — | ✓ | 1st |
| https://www.virginia.edu/assets/js/search_functions_v2.js?1 | 2 KB | — | ✓ | 1st |
| https://cdn.parsely.com/keys/virginia.edu/p.js | 19 KB | — | ✓ | 3rd |
| https://www.virginia.edu/assets/js/mobile-submenu-toggle.js | 1 KB | — | ✓ | 1st |
Consider code splitting or tree shaking to reduce unused code.
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.
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.
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.
This bundle has high unused code — code-split or tree-shake to ship only what executes.
Source: web.dev / Lighthouse coverage
CGreen HostingActionWhether the site is served from green-energy infrastructureREVIEW
Green Hosting
No green hosting detected
A+Text CompressionAll text resources are compressedPASS
A+Font Loading30 fonts (890 KB)PASS
Web fonts
30
890 KB total
Render-blocking
0
of 30
Dominant font-display
swap
Most common across fonts
Font loading timeline
- Subset this font — over 100 KB suggests Latin Extended or full glyph coverage that most pages don't need
- 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 ~77 KB and ~154 ms
A+Resource CachingAll resources properly cachedPASS
A+Critical Rendering PathNo render-blocking resourcesPASS
A+Resource HintsNo optimization neededPASS
A+Render-Blocking ResourcesNo render-blocking resources detectedPASS
A+Third-Party ResourcesNo third-party resources detectedPASS
Network Waterfall109 requests over 2263msINFO
Third-Party Script CostPer-script blocking time, transfer cost, and cache headersINFO
| Script | Category | Execution | Transfer | Unused | Monthly Cost | Verdict |
|---|---|---|---|---|---|---|
Unattributable Unattributable | Other | 655ms | 0 KB | — | $9/mo | Costly |
Google Tag Manager www.googletagmanager.com | Tag Manager | 409ms | 150 KB | 32% | $5/mo | Costly |
script.crazyegg.com script.crazyegg.com | Other | 366ms | 55 KB | 50% | $5/mo | Costly |
ajax.googleapis.com ajax.googleapis.com | Other | 320ms | 30 KB | — | $4/mo | Costly |
Google Tag Manager www.googletagmanager.com | Tag Manager | 221ms | 170 KB | 40% | $3/mo | Costly |
cdn.parsely.com cdn.parsely.com | Other | 108ms | 19 KB | — | $1/mo | Optional |
These scripts may cost more than they're worth
- Unattributable adds 655ms and costs ~$9/month
- Google Tag Manager adds 409ms and costs ~$5/month
- script.crazyegg.com adds 366ms and costs ~$5/month
- ajax.googleapis.com adds 320ms and costs ~$4/month
- Google Tag Manager adds 221ms and costs ~$3/month
74% of JavaScript execution time is spent on third-party scripts. Consider auditing which scripts are essential.
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 655ms of CPU time. Consider loading it asynchronously or replacing it with a lighter alternative.
This script has high main-thread execution time — optimize hot paths or defer.
Source: web.dev
Google Tag Manager takes 409ms of CPU time. Consider loading it asynchronously or replacing it with a lighter alternative.
This script has high main-thread execution time — optimize hot paths or defer.
Source: web.dev
script.crazyegg.com takes 366ms of CPU time. Consider loading it asynchronously or replacing it with a lighter alternative.
This script has high main-thread execution time — optimize hot paths or defer.
Source: web.dev
ajax.googleapis.com takes 320ms of CPU time. Consider loading it asynchronously or replacing it with a lighter alternative.
This script has high main-thread execution time — optimize hot paths or defer.
Source: web.dev
Google Tag Manager takes 221ms of CPU time. Consider loading it asynchronously or replacing it with a lighter alternative.
This script has high main-thread execution time — optimize hot paths or defer.
Source: web.dev