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.
1.37 s
Largest Contentful Paint Largest Contentful Paint — how long until the largest visible element loads. Under 2.5s is good.
5.34 s
Total Blocking Time Total Blocking Time — total time the main thread was blocked, preventing user input. Under 200ms is good.
57 ms
Cumulative Layout Shift Cumulative Layout Shift — measures visual stability. How much the page layout shifts during loading. Under 0.1 is good.
0.002
Speed Index Speed Index — how quickly content is visually displayed during load. Under 3.4s is good.
2.65 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.
5.41 s
Page Load Progression
FPage Weight BudgetAction6.0 MB transferred, 89 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
Remove unused CSS rules with tools like PurgeCSS to reduce stylesheet size.
CSS bundle is large — purge unused styles (PurgeCSS, Tailwind JIT) to reduce CSS payload.
Source: web.dev
DThird-Party ImpactAction100% third-party, 0 ms blockingFIX
DPage Weight InventoryAction89 resources · 6.0 MB · 185 KB savings availableFIX
~185.3 KiB of savings available
| # | Resource | Type | Size | Cache | Unused | 3rd party | Issues |
|---|---|---|---|---|---|---|---|
| — | — | ||||||
| 89 resources | 6.0 MiB | ||||||
CImage OptimizationAction27 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.
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.
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
BJS Execution Cost873ms total JS executionREVIEW
Main Thread Breakdown
| Script | Total | Scripting | Parse/Compile | Party |
|---|---|---|---|---|
| Unattributable | 287ms | 3ms | 0ms | 3rd |
| https://www.llnl.gov/ | 238ms | 3ms | 1ms | 3rd |
| https://www.llnl.gov/sites/www/files/js/js_MEw8oE9xi3neG9cgAsKjwho3FHhXukrcADmeP8PWbs0.js?scope=footer&delta=0&language=en&theme=sienna&include=eJxlkFFywzAIRC-kWEfSYIk4ODJoAMXJ7es2tetpvtC-XZgdgRl6Ip4xu2icbcgOyRXynXgK8GGv65oUCxpNHEYRty3c4vFKTXFbID-ZTZo8UE_ERapTC1kUY9HeoA6FoMo0wAzPgE-vxPfd-pWhVq4JqqOCk7DFl3TvI16Owj-JLOzInm59jIyrvakhaL7F9-gUFK1tN-iBaUHu8Z8ejrbBCJkhAkN9OWXbwXVLoH6Hd7LgBGetwEWWy7i1m1Q6l93othYLK45X0SX9fcwH-QJlRaXU | 214ms | 131ms | 37ms | 3rd |
| https://www.googletagmanager.com/gtag/js?id=G-CSLL4ZEK4L | 133ms | 113ms | 18ms | 3rd |
CJS BundlesAction20 scripts, 185 KB unusedREVIEW
Downloaded but never executed on this page.
| Script | Size | Unused | Minified | Party |
|---|---|---|---|---|
| https://www.llnl.gov/sites/www/files/js/js_MEw8oE9xi3neG9cgAsKjwho3FHhXukrcADmeP8PWbs0.js?scope=footer&delta=0&language=en&theme=sienna&include=eJxlkFFywzAIRC-kWEfSYIk4ODJoAMXJ7es2tetpvtC-XZgdgRl6Ip4xu2icbcgOyRXynXgK8GGv65oUCxpNHEYRty3c4vFKTXFbID-ZTZo8UE_ERapTC1kUY9HeoA6FoMo0wAzPgE-vxPfd-pWhVq4JqqOCk7DFl3TvI16Owj-JLOzInm59jIyrvakhaL7F9-gUFK1tN-iBaUHu8Z8ejrbBCJkhAkN9OWXbwXVLoH6Hd7LgBGetwEWWy7i1m1Q6l93othYLK45X0SX9fcwH-QJlRaXU | 155 KB | 105 KB (68%) | ✓ | 3rd |
| https://www.googletagmanager.com/gtag/js?id=G-CSLL4ZEK4L | 147 KB | 60 KB (41%) | ✓ | 3rd |
| https://www.llnl.gov/sites/www/files/js/js_k8oXBMlzypWW_AQwngBnyY54k4NQ1OjSMji7E8hppr8.js?scope=footer&delta=2&language=en&theme=sienna&include=eJxlkFFywzAIRC-kWEfSYIk4ODJoAMXJ7es2tetpvtC-XZgdgRl6Ip4xu2icbcgOyRXynXgK8GGv65oUCxpNHEYRty3c4vFKTXFbID-ZTZo8UE_ERapTC1kUY9HeoA6FoMo0wAzPgE-vxPfd-pWhVq4JqqOCk7DFl3TvI16Owj-JLOzInm59jIyrvakhaL7F9-gUFK1tN-iBaUHu8Z8ejrbBCJkhAkN9OWXbwXVLoH6Hd7LgBGetwEWWy7i1m1Q6l93othYLK45X0SX9fcwH-QJlRaXU | 29 KB | 20 KB (69%) | ✓ | 3rd |
| https://www.youtube.com/s/_/ytembeds/_/js/k=ytembeds.base.en_US.5f0apfZzpOA.2021.O/am=AAAABA/d=1/exm=base,root/ed=1/br=1/rs=AGKMywFg3MG1UeKh8ePjbhY_YEMv-NHjmA/m=r78Drb | 0 KB | — | ✓ | 3rd |
| https://dap.digitalgov.gov/Universal-Federated-Analytics-Min.js?agency=DOE&subagency=LLNL&sdor=fda.gov&dclink=true | 9 KB | — | ✓ | 3rd |
| https://static.cloudflareinsights.com/beacon.min.js/v8c78df7c7c0f484497ecbca7046644da1771523124516 | 0 KB | — | ✓ | 3rd |
| https://www.youtube.com/s/_/ytembeds/_/js/k=ytembeds.base.en_US.5f0apfZzpOA.2021.O/am=AAAABA/d=1/br=1/rs=AGKMywFg3MG1UeKh8ePjbhY_YEMv-NHjmA/m=root,base | 140 KB | — | ✓ | 3rd |
| https://www.youtube.com/s/player/1bb6ee63/player_embed_es6.vflset/en_US/base.js | 436 KB | — | ✓ | 3rd |
| https://www.youtube.com/iframe_api | 3 KB | — | ✓ | 3rd |
| https://static.doubleclick.net/instream/ad_status.js | 0 KB | — | ✓ | 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
CGreen HostingActionWhether the site is served from green-energy infrastructureREVIEW
Green Hosting
No green hosting detected
BHTTP Cachingno-cacheREVIEW
no-cache
| Directive | Value | Meaning |
|---|---|---|
| no-cache | — | Cache but always revalidate first |
A+Text CompressionAll text resources are compressedPASS
A+Font Loading10 fonts (1171 KB)PASS
Web fonts
10
1171 KB total
Render-blocking
0
of 10
Dominant font-display
swap
Most common across fonts
Font loading timeline
- Convert to woff2 for ~30% smaller file size
- Convert to woff2 for ~30% smaller file size
- Subset this font — over 100 KB suggests Latin Extended or full glyph coverage that most pages don't need
- Subset this font — over 100 KB suggests Latin Extended or full glyph coverage that most pages don't need
- Subset this font — over 100 KB suggests Latin Extended or full glyph coverage that most pages don't need
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 ~510 KB and ~1020 ms
A+Resource CachingAll resources properly cachedPASS
A+Critical Rendering PathNo render-blocking resourcesPASS
A+Resource HintsNo optimization neededPASS
Network Waterfall89 requests over 7071msINFO
Third-Party Script CostPer-script blocking time, transfer cost, and cache headersINFO
| Script | Category | Execution | Transfer | Unused | Monthly Cost | Verdict |
|---|---|---|---|---|---|---|
Unattributable Unattributable | Other | 287ms | 0 KB | — | $4/mo | Costly |
www.llnl.gov www.llnl.gov | Other | 238ms | 23 KB | — | $3/mo | Costly |
www.llnl.gov www.llnl.gov | Other | 214ms | 155 KB | 68% | $3/mo | Costly |
Google Tag Manager www.googletagmanager.com | Tag Manager | 133ms | 147 KB | 41% | $2/mo | Optional |
These scripts may cost more than they're worth
- Unattributable adds 287ms and costs ~$4/month
- www.llnl.gov adds 238ms and costs ~$3/month
- www.llnl.gov adds 214ms 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
Unattributable takes 287ms 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
www.llnl.gov takes 238ms 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
www.llnl.gov takes 214ms 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
68% of www.llnl.gov'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