Performance
· 15 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.
1.24 s
Largest Contentful Paint Largest Contentful Paint — how long until the largest visible element loads. Under 2.5s is good.
4.11 s
Total Blocking Time Total Blocking Time — total time the main thread was blocked, preventing user input. Under 200ms is good.
338 ms
Cumulative Layout Shift Cumulative Layout Shift — measures visual stability. How much the page layout shifts during loading. Under 0.1 is good.
0.608
Speed Index Speed Index — how quickly content is visually displayed during load. Under 3.4s is good.
1.72 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.
7.39 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 sFPage Weight BudgetAction5.3 MB transferred, 140 requestsFIX
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
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
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 ImpactAction100% third-party, 0 ms blockingFIX
FJS BundlesAction36 scripts, 598 KB unusedFIX
Downloaded but never executed on this page.
| Script | Size | Unused | Minified | Party |
|---|---|---|---|---|
| https://www.googletagmanager.com/gtag/js?id=G-5Z60EH83Q9&cx=c>m=4e64h1 | 174 KB | 71 KB (41%) | ✓ | 3rd |
| https://www.googletagmanager.com/gtag/js?id=AW-17193693909&cx=c>m=4e64h1 | 145 KB | 62 KB (43%) | ✓ | 3rd |
| https://www.googletagmanager.com/gtag/js?id=AW-17728352691&cx=c>m=4e64h1 | 145 KB | 62 KB (43%) | ✓ | 3rd |
| https://www.googletagmanager.com/gtag/js?id=G-DTEQ1JM2SG&cx=c>m=4e64h1 | 156 KB | 62 KB (40%) | ✓ | 3rd |
| https://www.googletagmanager.com/gtm.js?id=GTM-P6F85Q5 | 206 KB | 57 KB (28%) | ✓ | 3rd |
| https://www.googletagmanager.com/gtag/js?id=AW-1030829117&cx=c>m=4e64h1 | 145 KB | 55 KB (38%) | ✓ | 3rd |
| https://www.googletagmanager.com/gtag/js?id=DC-15114839&cx=c>m=4e64h1 | 131 KB | 55 KB (42%) | ✓ | 3rd |
| https://connect.facebook.net/en_US/fbevents.js | 97 KB | 33 KB (35%) | ✓ | 3rd |
| https://www.vt.edu/global_assets/templates/one/js/root.min.js | 48 KB | 33 KB (70%) | ✓ | 3rd |
| https://script.crazyegg.com/pages/versioned/common-scripts/4ce8c7df8d425cc50464576824ed91eb.js | 55 KB | 30 KB (54%) | ✓ | 3rd |
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
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
FPage Weight InventoryAction140 resources · 5.3 MB · 598 KB savings availableFIX
~598.0 KiB of savings available
| # | Resource | Type | Size | Cache | Unused | 3rd party | Issues |
|---|---|---|---|---|---|---|---|
| — | — | ||||||
| 140 resources | 5.3 MiB | ||||||
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
CJS Execution CostAction1522ms total JS executionREVIEW
Main Thread Breakdown
| Script | Total | Scripting | Parse/Compile | Party |
|---|---|---|---|---|
| https://www.googletagmanager.com/gtm.js?id=GTM-P6F85Q5 | 256ms | 213ms | 24ms | 3rd |
| https://www.assets.cms.vt.edu/font-awesome/archives-pro/5.latest/js/all.min.js | 191ms | 27ms | 148ms | 3rd |
| https://www.vt.edu/ | 167ms | 5ms | 1ms | 3rd |
| Unattributable | 149ms | 7ms | 0ms | 3rd |
| https://www.vt.edu/global_assets/templates/one/js/root.min.js | 103ms | 22ms | 5ms | 3rd |
| https://www.googletagmanager.com/gtag/js?id=AW-1030829117&cx=c>m=4e64h1 | 86ms | 74ms | 11ms | 3rd |
| https://www.googletagmanager.com/gtag/js?id=G-5Z60EH83Q9&cx=c>m=4e64h1 | 81ms | 63ms | 10ms | 3rd |
| https://www.assets.cms.vt.edu/jquery/archives/jquery-3.cms.min.js | 80ms | 62ms | 2ms | 3rd |
| https://www.googletagmanager.com/gtag/js?id=AW-17728352691&cx=c>m=4e64h1 | 76ms | 63ms | 13ms | 3rd |
| https://script.crazyegg.com/pages/versioned/common-scripts/4ce8c7df8d425cc50464576824ed91eb.js | 70ms | 62ms | 5ms | 3rd |
Showing top 10 of 14 scripts
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 Loading14 fonts (618 KB)PASS
Web fonts
14
618 KB total
Render-blocking
0
of 14
Dominant font-display
swap
Most common across fonts
Font loading timeline
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 CachingAll resources properly cachedPASS
A+Critical Rendering PathNo render-blocking resourcesPASS
A+Resource HintsNo optimization neededPASS
AHTTP Cachingmax-age=600 (10 minutes)PASS
max-age=600
| Directive | Value | Meaning |
|---|---|---|
| max-age | 600 | Cache for 10 minutes |
Network Waterfall140 requests over 3473msINFO
Third-Party Script CostPer-script blocking time, transfer cost, and cache headersINFO
| Script | Category | Execution | Transfer | Unused | Monthly Cost | Verdict |
|---|---|---|---|---|---|---|
Google Tag Manager www.googletagmanager.com | Tag Manager | 256ms | 206 KB | 28% | $3/mo | Costly |
www.assets.cms.vt.edu www.assets.cms.vt.edu | Other | 191ms | 1704 KB | — | $3/mo | Optional |
www.vt.edu www.vt.edu | Other | 167ms | 16 KB | — | $2/mo | Optional |
Unattributable Unattributable | Other | 149ms | 0 KB | — | $2/mo | Optional |
www.vt.edu www.vt.edu | Other | 103ms | 48 KB | 70% | $1/mo | Optional |
Google Tag Manager www.googletagmanager.com | Tag Manager | 86ms | 145 KB | 38% | $1/mo | Optional |
Google Tag Manager www.googletagmanager.com | Tag Manager | 81ms | 174 KB | 41% | $1/mo | Optional |
www.assets.cms.vt.edu www.assets.cms.vt.edu | Other | 80ms | 30 KB | — | $1/mo | Optional |
Google Tag Manager www.googletagmanager.com | Tag Manager | 76ms | 145 KB | 43% | $1/mo | Optional |
script.crazyegg.com script.crazyegg.com | Other | 70ms | 55 KB | 54% | $1/mo | Optional |
Google Tag Manager www.googletagmanager.com | Tag Manager | 66ms | 145 KB | 43% | $1/mo | Optional |
Google Tag Manager www.googletagmanager.com | Tag Manager | 66ms | 156 KB | 40% | $1/mo | Optional |
Facebook Pixel connect.facebook.net | Advertising | 66ms | 97 KB | 28% | $1/mo | Optional |
Google Tag Manager www.googletagmanager.com | Tag Manager | 66ms | 131 KB | 42% | $1/mo | Optional |
These scripts may cost more than they're worth
- Google Tag Manager adds 256ms and costs ~$3/month
100% 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
Google Tag Manager takes 256ms 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
70% of www.vt.edu's code is unused. The script may be loading features you don't use.
Bundle has high unused-code ratio — tree-shaking and route-splitting recover the wasted bytes.
Source: web.dev
54% of script.crazyegg.com's code is unused. The script may be loading features you don't use.
Bundle has high unused-code ratio — tree-shaking and route-splitting recover the wasted bytes.
Source: web.dev