Performance
· 27 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.
3.58 s
Largest Contentful Paint Largest Contentful Paint — how long until the largest visible element loads. Under 2.5s is good.
10.49 s
Total Blocking Time Total Blocking Time — total time the main thread was blocked, preventing user input. Under 200ms is good.
893 ms
Cumulative Layout Shift Cumulative Layout Shift — measures visual stability. How much the page layout shifts during loading. Under 0.1 is good.
0.000
Speed Index Speed Index — how quickly content is visually displayed during load. Under 3.4s is good.
4.93 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.
10.65 s
Page Load Progression
FJS Execution CostAction3543ms total JS executionFIX
Main Thread Breakdown
| Script | Total | Scripting | Parse/Compile | Party |
|---|---|---|---|---|
| https://www.readingrockets.org/ | 1040ms | 21ms | 1ms | 1st |
| https://www.readingrockets.org/sites/default/files/js/js_NV6AhuKEGPT5fCuOs8ub6sybUcptyCfgOBuWS8vcvpQ.js?scope=footer&delta=1&language=en&theme=readingrockets_d9&include=eJxlj9sOwiAMQH-IyLOPfgnpRtN1louFqfj1Ml7c4stJOIc2KaVEgq4CWeowdH5fYIX3WQYj8Gl2h1FPbmOHggFjLXYGTVtBGeGFFSxJmkDcWn4qgwIp5MVliPtfBM-RNM13rMX563Hory3doBpV57lkgWbXx4ba3JxChsoTC9e297KAoh28RQ69pXjwlfvOYJ6Mr2IHx7FfvNRqgw | 792ms | 191ms | 21ms | 1st |
| Unattributable | 657ms | 95ms | 0ms | 1st |
| https://www.googletagmanager.com/gtm.js?id=GTM-N57G8NB | 270ms | 221ms | 44ms | 3rd |
| https://www.googletagmanager.com/gtag/js?id=G-JEBE1MXWDM&cx=c>m=4e66h0 | 256ms | 199ms | 55ms | 3rd |
| https://script.hotjar.com/modules.c7cfa5e5dff97bece8fc.js | 216ms | 188ms | 24ms | 3rd |
| https://kit.fontawesome.com/eb1ea169a9.js | 126ms | 123ms | 2ms | 3rd |
| https://www.readingrockets.org/core/assets/vendor/jquery/jquery.min.js?v=4.0.0 | 108ms | 36ms | 17ms | 1st |
| https://www.readingrockets.org/sites/default/files/css/css_GWGaC2pSWfmXW6t4xBhs67XT6liRNqDJwGQ_JTVtS7A.css?delta=1&language=en&theme=readingrockets_d9&include=eJx9UUFywyAM_JDHnPsaRhjFpsGISqKOf1_Fk8Sd2s2FQbuLtFoCqiJ7oSFB9jIBpzL60FSpiBNds9XdQIwucquQe_iEW1eBYWSokzzhHelbqS3kJBPGjuPo8WYjirW3XldxR2hTteQx44xFxQ3A1ATzRiyo4C5E9mKvx0zBng8iO_ay4HEOGCNGHzIN1zNFhYLZj5yiZ1o6Roi2KJsaVXz8uFuI5_DD2ZHKIMJEsxdlUBzXE9Fv3wdyMsQCwRNqTiX5fzxtnCLIPaAD-2fnt4qvZim_Vaj93IngMV1WUZxdsKLTtZLle1nd69Z9J1zEbWc_U2wZfwBXoPwK | 77ms | 0ms | 0ms | 1st |
DPage Weight InventoryAction63 resources · 1.5 MB · 178 KB savings availableFIX
~178.0 KiB of savings available
| # | Resource | Type | Size | Cache | Unused | 3rd party | Issues |
|---|---|---|---|---|---|---|---|
| — | — | ||||||
| 63 resources | 1.5 MiB | ||||||
BPage Weight Budget1.5 MB transferred, 63 requestsREVIEW
BThird-Party Impact41% third-party, 0 ms blockingREVIEW
BImage Optimization25 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
CJS BundlesAction16 scripts, 178 KB unusedREVIEW
Downloaded but never executed on this page.
| Script | Size | Unused | Minified | Party |
|---|---|---|---|---|
| https://www.googletagmanager.com/gtag/js?id=G-JEBE1MXWDM&cx=c>m=4e66h0 | 174 KB | 71 KB (41%) | ✓ | 3rd |
| https://www.googletagmanager.com/gtm.js?id=GTM-N57G8NB | 134 KB | 69 KB (52%) | ✓ | 3rd |
| https://script.hotjar.com/modules.c7cfa5e5dff97bece8fc.js | 56 KB | 38 KB (67%) | ✓ | 3rd |
| https://unpkg.com/imagesloaded@4.1.4/imagesloaded.pkgd.min.js | 2 KB | — | ✓ | 3rd |
| https://www.readingrockets.org/sites/default/files/js/js_2Mqa-U2O2WtOeSW7MAGsfgEy7k7-eT981WvVnRpzoEc.js?scope=header&delta=0&language=en&theme=readingrockets_d9&include=eJxlj9sOwiAMQH-IyLOPfgnpRtN1louFqfj1Ml7c4stJOIc2KaVEgq4CWeowdH5fYIX3WQYj8Gl2h1FPbmOHggFjLXYGTVtBGeGFFSxJmkDcWn4qgwIp5MVliPtfBM-RNM13rMX563Hory3doBpV57lkgWbXx4ba3JxChsoTC9e297KAoh28RQ69pXjwlfvOYJ6Mr2IHx7FfvNRqgw | 0 KB | — | ✓ | 1st |
| https://kit.fontawesome.com/eb1ea169a9.js | 5 KB | — | ✓ | 3rd |
| https://www.readingrockets.org/cdn-cgi/scripts/5c5dd728/cloudflare-static/email-decode.min.js | 1 KB | — | ✓ | 1st |
| https://www.readingrockets.org/modules/contrib/google_tag/js/gtm.js?tg2bnu | 1 KB | — | ✓ | 1st |
| https://cdn.jsdelivr.net/npm/focus-visible@5.2.0/dist/focus-visible.min.js | 2 KB | — | ✓ | 3rd |
| https://www.readingrockets.org/core/assets/vendor/jquery/jquery.min.js?v=4.0.0 | 29 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
BHTTP/3 (QUIC)HTTP/3 not advertisedREVIEW
BServer-Timing ObservabilityNo Server-Timing header foundREVIEW
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 Loading10 fonts (196 KB)PASS
Web fonts
10
196 KB total
Render-blocking
0
of 10
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 Hints3 hints, 0 missing preconnectsPASS
Current Resource Hints
3 resource hints configured
A+Compression AlgorithmMain response uses brotliPASS
A+LCP Image PreloadLCP preload audit not availablePASS
A+Main HTML Cache-ControlMain HTML max-age=300 (≤ 5min) is appropriatePASS
A+Server Response Intelligence2 server-response signal(s) detectedPASS
A+Render-Blocking ResourcesNo render-blocking resources detectedPASS
A+Third-Party ResourcesNo third-party resources detectedPASS
AJavaScript Blocking1 JS blocking issue(s) detectedPASS
A+CSS Performance DepthNo CSS performance depth issues detectedPASS
A+HTTP Cachingmax-age=300 (5 minutes)PASS
max-age=300, public
| Directive | Value | Meaning |
|---|---|---|
| max-age | 300 | Cache for 5 minutes |
| public | — | Any cache may store this response |
Network Waterfall63 requests over 1461msINFO
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 | 270ms | 134 KB | 52% | $4/mo | Costly |
Google Tag Manager www.googletagmanager.com | Tag Manager | 256ms | 174 KB | 41% | $3/mo | Costly |
Hotjar script.hotjar.com | Session Replay | 216ms | 56 KB | 67% | $3/mo | Costly |
kit.fontawesome.com kit.fontawesome.com | Other | 126ms | 5 KB | — | $2/mo | Optional |
These scripts may cost more than they're worth
- Google Tag Manager adds 270ms and costs ~$4/month
- Google Tag Manager adds 256ms and costs ~$3/month
- Hotjar adds 216ms and costs ~$3/month
Google Tag Manager takes 270ms 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
52% of Google Tag Manager'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
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
Hotjar takes 216ms 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
67% of Hotjar'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
Real-User Performance (CrUX)Field metrics from the Chrome User Experience ReportINFO
Chrome User Experience (CrUX)
Real-user metrics from the Chrome UX Report (2026-05-25 — 2026-06-21)
LCP (p75)
2557 ms
74% good
INP (p75)
82 ms
95% good
CLS (p75)
0.020
91% good
FCP (p75)
1604 ms
TTFB (p75)
667 ms
Image Optimization44 images, 1039 KB total, 55 KB wastedINFO
Image Optimization Audit
Total Images
44
Total Size
1039 KB
Oversized
3
Wasted
55 KB