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.
3.77 s
Total Blocking Time Total Blocking Time — total time the main thread was blocked, preventing user input. Under 200ms is good.
1.13 s
Cumulative Layout Shift Cumulative Layout Shift — measures visual stability. How much the page layout shifts during loading. Under 0.1 is good.
0.070
Speed Index Speed Index — how quickly content is visually displayed during load. Under 3.4s is good.
3.93 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.
7.25 s
Page Load Progression
1.0 s 2.0 s
3.1 s
4.1 s
5.1 s
6.1 s 7.2 s
8.2 sFPage Weight BudgetAction4.3 MB transferred, 306 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
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 Execution CostAction5873ms total JS executionFIX
Main Thread Breakdown
| Script | Total | Scripting | Parse/Compile | Party |
|---|---|---|---|---|
| https://www.sigmaaldrich.com/_next/static/chunks/framework-8593b37603e77b1e.js | 1807ms | 1578ms | 4ms | 3rd |
| https://www.sigmaaldrich.com/ruxitagentjs_ICA15789NPRTUVXfhqrux_10335260306043831.js | 561ms | 482ms | 11ms | 3rd |
| Unattributable | 558ms | 22ms | 0ms | 3rd |
| https://www.sigmaaldrich.com/US/en | 496ms | 57ms | 3ms | 3rd |
| https://www.googletagmanager.com/gtm.js?id=GTM-TXMJ2GG>m_auth=>m_preview=>m_cookies_win=x | 441ms | 389ms | 27ms | 3rd |
| https://www.googletagmanager.com/gtag/destination?id=AW-497007017&cx=c>m=4e64k1 | 278ms | 263ms | 12ms | 3rd |
| https://edge.fullstory.com/s/fs.js | 250ms | 214ms | 9ms | 3rd |
| https://www.sigmaaldrich.com/_next/static/chunks/pages/%5Bcountry%5D/%5Blanguage%5D-00abce956aebeb19.js | 242ms | 220ms | 1ms | 3rd |
| https://www.sigmaaldrich.com/_next/static/chunks/pages/_app-e8d8f0583ad6d04c.js | 215ms | 156ms | 59ms | 3rd |
| https://cdn.optimizely.com/js/29864900014.js | 108ms | 86ms | 22ms | 3rd |
Showing top 10 of 23 scripts
FJS BundlesAction106 scripts, 1.3 MB unusedFIX
Downloaded but never executed on this page.
| Script | Size | Unused | Minified | Party |
|---|---|---|---|---|
| https://www.sigmaaldrich.com/_next/static/chunks/pages/_app-e8d8f0583ad6d04c.js | 562 KB | 260 KB (47%) | ✓ | 3rd |
| https://www.sigmaaldrich.com/_next/static/chunks/8669-5cfc2e3fd97aca7a.js | 138 KB | 115 KB (84%) | ✓ | 3rd |
| https://www.sigmaaldrich.com/_next/static/chunks/4768-9da82a5f9303cd97.js | 172 KB | 111 KB (64%) | ✓ | 3rd |
| https://www.sigmaaldrich.com/_next/static/chunks/main-9b669c732468f591.js | 111 KB | 85 KB (79%) | ✓ | 3rd |
| https://cdn.cookielaw.org/scripttemplates/202602.1.0/otBannerSdk.js | 129 KB | 69 KB (53%) | ✓ | 3rd |
| https://www.googletagmanager.com/gtag/destination?id=DC-11536248&cx=c>m=4e64k1 | 130 KB | 62 KB (48%) | ✓ | 3rd |
| https://www.googletagmanager.com/gtag/destination?id=DC-15223238&cx=c>m=4e64k1 | 129 KB | 61 KB (47%) | ✓ | 3rd |
| https://www.googletagmanager.com/gtag/js?id=G-BQZS3WQYGJ&cx=c>m=4e64k1 | 165 KB | 61 KB (37%) | ✓ | 3rd |
| https://www.googletagmanager.com/gtag/destination?id=AW-497007017&cx=c>m=4e64k1 | 141 KB | 60 KB (43%) | ✓ | 3rd |
| https://www.googletagmanager.com/gtag/destination?id=AW-1034663491&cx=c>m=4e64k1 | 134 KB | 54 KB (40%) | ✓ | 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 InventoryAction306 resources · 4.3 MB · 1.3 MB savings availableFIX
~1.3 MiB of savings available
| # | Resource | Type | Size | Cache | Unused | 3rd party | Issues |
|---|---|---|---|---|---|---|---|
| — | — | ||||||
| 306 resources | 4.3 MiB | ||||||
FHTTP CachingActionNo cache headersFIX
No Cache-Control header
Adding a Cache-Control header can significantly improve repeat-visit performance.
CImage OptimizationAction97 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
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 Loading1 fonts (35 KB)PASS
Web fonts
1
35 KB total
Render-blocking
0
of 1
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
Network Waterfall306 requests over 13437msINFO
Third-Party Script CostPer-script blocking time, transfer cost, and cache headersINFO
| Script | Category | Execution | Transfer | Unused | Monthly Cost | Verdict |
|---|---|---|---|---|---|---|
www.sigmaaldrich.com www.sigmaaldrich.com | Other | 1807ms | 43 KB | — | $24/mo | Costly |
www.sigmaaldrich.com www.sigmaaldrich.com | Other | 561ms | 127 KB | 37% | $7/mo | Costly |
Unattributable Unattributable | Other | 558ms | 0 KB | — | $7/mo | Costly |
www.sigmaaldrich.com www.sigmaaldrich.com | Other | 496ms | 241 KB | — | $7/mo | Costly |
Google Tag Manager www.googletagmanager.com | Tag Manager | 441ms | 206 KB | 24% | $6/mo | Costly |
Google Tag Manager www.googletagmanager.com | Tag Manager | 278ms | 141 KB | 43% | $4/mo | Costly |
edge.fullstory.com edge.fullstory.com | Other | 250ms | 80 KB | 35% | $3/mo | Costly |
www.sigmaaldrich.com www.sigmaaldrich.com | Other | 242ms | 9 KB | — | $3/mo | Costly |
www.sigmaaldrich.com www.sigmaaldrich.com | Other | 215ms | 562 KB | 47% | $3/mo | Costly |
Optimizely cdn.optimizely.com | A/B Testing | 108ms | 141 KB | 21% | $1/mo | Optional |
cdn.evgnet.com cdn.evgnet.com | Other | 98ms | 49 KB | 50% | $1/mo | Optional |
OneTrust cdn.cookielaw.org | Consent | 97ms | 129 KB | 53% | $1/mo | Essential |
Google Tag Manager www.googletagmanager.com | Tag Manager | 87ms | 165 KB | 37% | $1/mo | Optional |
OneTrust cdn.cookielaw.org | Consent | 83ms | 9 KB | — | $1/mo | Essential |
www.sigmaaldrich.com www.sigmaaldrich.com | Other | 70ms | 7 KB | — | $1/mo | Optional |
Google Tag Manager www.googletagmanager.com | Tag Manager | 69ms | 130 KB | 48% | $1/mo | Optional |
siteintercept.qualtrics.com siteintercept.qualtrics.com | Other | 69ms | 36 KB | 59% | $1/mo | Optional |
www.sigmaaldrich.com www.sigmaaldrich.com | Other | 67ms | 11 KB | — | $1/mo | Optional |
tag.demandbase.com tag.demandbase.com | Other | 61ms | 50 KB | 74% | $1/mo | Optional |
Google Tag Manager www.googletagmanager.com | Tag Manager | 56ms | 134 KB | 40% | $1/mo | Optional |
Google Tag Manager www.googletagmanager.com | Tag Manager | 55ms | 129 KB | 47% | $1/mo | Optional |
api.demandbase.com api.demandbase.com | Other | 54ms | 1 KB | — | $1/mo | Optional |
Microsoft Clarity scripts.clarity.ms | Session Replay | 50ms | 26 KB | — | $1/mo | Optional |
These scripts may cost more than they're worth
- www.sigmaaldrich.com adds 1807ms and costs ~$24/month
- www.sigmaaldrich.com adds 561ms and costs ~$7/month
- Unattributable adds 558ms and costs ~$7/month
- www.sigmaaldrich.com adds 496ms and costs ~$7/month
- Google Tag Manager adds 441ms and costs ~$6/month
- Google Tag Manager adds 278ms and costs ~$4/month
- edge.fullstory.com adds 250ms and costs ~$3/month
- www.sigmaaldrich.com adds 242ms and costs ~$3/month
- www.sigmaaldrich.com adds 215ms 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
www.sigmaaldrich.com takes 1807ms 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.sigmaaldrich.com takes 561ms 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
Unattributable takes 558ms 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.sigmaaldrich.com takes 496ms 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 441ms 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 278ms 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
edge.fullstory.com takes 250ms 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.sigmaaldrich.com takes 242ms 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.sigmaaldrich.com takes 215ms 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
50% of cdn.evgnet.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
53% of OneTrust'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
59% of siteintercept.qualtrics.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
74% of tag.demandbase.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