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.
1.22 s
Largest Contentful Paint Largest Contentful Paint — how long until the largest visible element loads. Under 2.5s is good.
1.74 s
Total Blocking Time Total Blocking Time — total time the main thread was blocked, preventing user input. Under 200ms is good.
124 ms
Cumulative Layout Shift Cumulative Layout Shift — measures visual stability. How much the page layout shifts during loading. Under 0.1 is good.
0.051
Speed Index Speed Index — how quickly content is visually displayed during load. Under 3.4s is good.
2.63 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.
3.54 s
Page Load Progression
FPage Weight BudgetAction55.6 MB transferred, 99 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
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
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
DThird-Party ImpactAction100% third-party, 0 ms blockingFIX
DJS BundlesAction36 scripts, 437 KB unusedFIX
Downloaded but never executed on this page.
| Script | Size | Unused | Minified | Party |
|---|---|---|---|---|
| https://www.googletagmanager.com/gtag/js?id=G-YXS8H95P3G&cx=c>m=4e64h1 | 173 KB | 116 KB (67%) | ✓ | 3rd |
| https://www.googletagmanager.com/gtag/destination?id=G-YXS8H95P3G&cx=c>m=4e64h1 | 174 KB | 71 KB (41%) | ✓ | 3rd |
| https://www.astm.org/_next/static/chunks/7273-57e2012880982d18.js | 109 KB | 67 KB (62%) | ✓ | 3rd |
| https://www.googletagmanager.com/gtm.js?id=GTM-54ZG9PKC | 153 KB | 61 KB (40%) | ✓ | 3rd |
| https://www.astm.org/_next/static/chunks/4245-89881a608d3d3b37.js | 105 KB | 58 KB (56%) | ✓ | 3rd |
| https://script.hotjar.com/modules.6a0f3932cb1341a35c18.js | 57 KB | 38 KB (67%) | ✓ | 3rd |
| https://www.astm.org/_next/static/chunks/992-e94673434af1789a.js | 58 KB | 26 KB (46%) | ✓ | 3rd |
| https://www.astm.org/_next/static/chunks/app/layout-49b3769bb30c5179.js | 2 KB | — | ✓ | 3rd |
| https://www.astm.org/_next/static/chunks/1918-2c1929e041689eff.js | 5 KB | — | ✓ | 3rd |
| https://www.astm.org/_next/static/chunks/140bf7e7-0d5934ba9777d20e.js | 2 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
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 InventoryAction99 resources · 55.6 MB · 437 KB savings availableFIX
~437.0 KiB of savings available
| # | Resource | Type | Size | Cache | Unused | 3rd party | Issues |
|---|---|---|---|---|---|---|---|
| — | — | ||||||
| 99 resources | 55.6 MiB | ||||||
FHTTP CachingActionNo cache headersFIX
No Cache-Control header
Adding a Cache-Control header can significantly improve repeat-visit performance.
CImage OptimizationAction15 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 CostAction1331ms total JS executionREVIEW
Main Thread Breakdown
| Script | Total | Scripting | Parse/Compile | Party |
|---|---|---|---|---|
| Unattributable | 463ms | 24ms | 0ms | 3rd |
| https://www.astm.org/_next/static/chunks/webpack-955ea9e689c54099.js | 172ms | 170ms | 0ms | 3rd |
| https://www.astm.org/_next/static/chunks/3131-221e6607f27d6926.js | 155ms | 132ms | 3ms | 3rd |
| https://www.astm.org/ | 153ms | 11ms | 7ms | 3rd |
| https://www.googletagmanager.com/gtm.js?id=GTM-54ZG9PKC | 93ms | 69ms | 14ms | 3rd |
| https://www.googletagmanager.com/gtag/destination?id=G-YXS8H95P3G&cx=c>m=4e64h1 | 84ms | 73ms | 10ms | 3rd |
| https://script.hotjar.com/modules.6a0f3932cb1341a35c18.js | 83ms | 68ms | 6ms | 3rd |
| https://www.astm.org/_next/static/chunks/c7879cf7-fabe25011515220e.js | 79ms | 46ms | 4ms | 3rd |
| https://www.astm.org/_next/static/chunks/992-e94673434af1789a.js | 50ms | 29ms | 5ms | 3rd |
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 Loading5 fonts (456 KB)PASS
Web fonts
5
456 KB total
Render-blocking
0
of 5
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
- 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 ~155 KB and ~310 ms
A+Resource CachingAll resources properly cachedPASS
A+Critical Rendering PathNo render-blocking resourcesPASS
A+Resource HintsNo optimization neededPASS
Network Waterfall99 requests over 34641msINFO
Third-Party Script CostPer-script blocking time, transfer cost, and cache headersINFO
| Script | Category | Execution | Transfer | Unused | Monthly Cost | Verdict |
|---|---|---|---|---|---|---|
Unattributable Unattributable | Other | 463ms | 0 KB | — | $3/mo | Costly |
www.astm.org www.astm.org | Other | 172ms | 2 KB | — | $1/mo | Optional |
www.astm.org www.astm.org | Other | 155ms | 46 KB | — | $1/mo | Optional |
www.astm.org www.astm.org | Other | 153ms | 53 KB | — | $1/mo | Optional |
Google Tag Manager www.googletagmanager.com | Tag Manager | 93ms | 153 KB | 40% | $1/mo | Optional |
Google Tag Manager www.googletagmanager.com | Tag Manager | 84ms | 174 KB | 41% | $0/mo | Optional |
Hotjar script.hotjar.com | Session Replay | 83ms | 57 KB | 67% | $0/mo | Optional |
www.astm.org www.astm.org | Other | 79ms | 54 KB | — | $0/mo | Optional |
www.astm.org www.astm.org | Other | 50ms | 58 KB | 46% | $0/mo | Optional |
These scripts may cost more than they're worth
- Unattributable adds 463ms 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 463ms 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