Browsers will use heuristic caching, which can be unpredictable. Set explicit cache headers.
No Cache-Control header
Adding a Cache-Control header can significantly improve repeat-visit performance.
C
Page Weight Budget
Action
1.6 MB transferred, 51 requests
REVIEW
1.6 MB transferred, 51 requests
Info::
i
Page weighs 5.1 MB (1.6 MB transferred)
Warning::
!
JavaScript is 1.4 MB — consider code splitting or lazy loading
Large JavaScript bundles delay interactivity. Split code by route or defer non-critical scripts.
Got: 1.4 MB
Info::
i
51 HTTP requests
Info::
i
Estimated 0.34 g CO2 per page load
1.6 MBtransferred
51 requests
0.34 g CO2 per page load
JavaScript1.4 MiB84%
Fonts125.2 KiB8%
Other48.4 KiB3%
CSS38.6 KiB2%
Images36.6 KiB2%
HTML16.7 KiB1%
Other1.6 KiB0%
Other712 B0%
Other562 B0%
Other562 B0%
Other0 B0%
02.4 MB4.9 MB
Approaching limit
Large JavaScript bundles delay interactivity. Split code by route or defer non-critical scripts.
Why this matters
JavaScript bundle is large — code-split routes and lazy-load off-screen components to defer.
Source: web.dev
B
Image Optimization
3 images, 0 KB saveable
REVIEW
3 images, 0 KB saveable
Warning::
!
https://cdn.worldometers.info/img/worldometers-log... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
3images37 KB
0oversized-0 KB
3legacy format
1missing dimensionsCLS risk
Set explicit width and height to prevent CLS.
Why this matters
Image without explicit width/height — browser can't reserve space; CLS jumps when image loads.
Source: web.dev / Core Web Vitals
A+
Text Compression
All text resources are compressed
PASS
All text resources are compressed
Info::
✓
All text resources are compressed
All text resources are properly compressed.
A+
Font Loading
3 fonts (125 KB)
PASS
3 fonts (125 KB)
Info::
i
3 font(s) use font-display: swap (FOUT risk but functional)
Web fonts
3
125 KB total
Render-blocking
0
of 3
Dominant font-display
swap
Most common across fonts
Font loading timeline
TransferFOIT (block)FOUT (swap)
normal.woff2woff2swap
Size35 KB
Load time78 ms
Start500 ms
RiskFOUT — text flashes from fallback to web font
normal.woff2woff2swap
Size48 KB
Load time78 ms
Start500 ms
RiskFOUT — text flashes from fallback to web font
memvYaGs126MiZpBA-UvWbX...woff2swap
Size42 KB
Load time71 ms
Start4.5 s
RiskFOUT — text flashes from fallback to web font
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 Caching
All resources properly cached
PASS
All resources properly cached
Info::
✓
No caching issues found
All static resources have appropriate caching headers.
A+
Critical Rendering Path
No render-blocking resources
PASS
No render-blocking resources
Info::
✓
No render-blocking resources detected
A+
Resource Hints
No optimization needed
PASS
No optimization needed
Info::
✓
No resource hint issues
A+
Green Hosting
Whether the site is served from green-energy infrastructure
PASS
Green Hosting
This site is hosted on green energy infrastructure
Provider: Cloudflare
Network Waterfall
51 requests over 5395ms
INFO
HTML JavaScript CSS Images Fonts XHR/Fetch Other
Third-Party Script Cost
Per-script blocking time, transfer cost, and cache headers
INFO
100%of JavaScript execution is third-party
First-party Third-party5293ms · 645KB · $91/mo
Script
Category
Execution
Transfer
Unused
Monthly Cost
Verdict
Unattributable
Unattributable
Other
3396ms
0 KB
—
$59/mo
Costly
code.jquery.com
code.jquery.com
Other
925ms
30 KB
—
$16/mo
Costly
www.worldometers.info
www.worldometers.info
Other
615ms
17 KB
—
$11/mo
Costly
Google Tag Manager
www.googletagmanager.com
Tag Manager
90ms
158 KB
39%
$2/mo
Optional
fundingchoicesmessages.google.com
fundingchoicesmessages.google.com
Other
85ms
66 KB
—
$1/mo
Optional
securepubads.g.doubleclick.net
securepubads.g.doubleclick.net
Other
65ms
187 KB
77%
$1/mo
Optional
a.pub.network
a.pub.network
Other
59ms
186 KB
82%
$1/mo
Optional
www.worldometers.info
www.worldometers.info
Other
59ms
0 KB
—
$1/mo
Optional
Unattributable
Other
Costly
Execution3396ms
Transfer0 KB
Monthly Cost$59/mo
code.jquery.com
Other
Costly
Execution925ms
Transfer30 KB
Monthly Cost$16/mo
www.worldometers.info
Other
Costly
Execution615ms
Transfer17 KB
Monthly Cost$11/mo
Google Tag Manager
Tag Manager
Optional
Execution90ms
Transfer158 KB
Unused39%
Monthly Cost$2/mo
fundingchoicesmessages.google.com
Other
Optional
Execution85ms
Transfer66 KB
Monthly Cost$1/mo
securepubads.g.doubleclick.net
Other
Optional
Execution65ms
Transfer187 KB
Unused77%
Monthly Cost$1/mo
a.pub.network
Other
Optional
Execution59ms
Transfer186 KB
Unused82%
Monthly Cost$1/mo
www.worldometers.info
Other
Optional
Execution59ms
Transfer0 KB
Monthly Cost$1/mo
These scripts may cost more than they're worth
Unattributable adds 3396ms and costs ~$59/month
code.jquery.com adds 925ms and costs ~$16/month
www.worldometers.info adds 615ms and costs ~$11/month
100% of JavaScript execution time is spent on third-party scripts. Consider auditing which scripts are essential.
Why this matters
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 3396ms of CPU time. Consider loading it asynchronously or replacing it with a lighter alternative.
Why this matters
This script has high main-thread execution time — optimize hot paths or defer.
Source: web.dev
code.jquery.com takes 925ms of CPU time. Consider loading it asynchronously or replacing it with a lighter alternative.
Why this matters
This script has high main-thread execution time — optimize hot paths or defer.
Source: web.dev
www.worldometers.info takes 615ms of CPU time. Consider loading it asynchronously or replacing it with a lighter alternative.
Why this matters
This script has high main-thread execution time — optimize hot paths or defer.
Source: web.dev
77% of securepubads.g.doubleclick.net's code is unused. The script may be loading features you don't use.
Why this matters
Bundle has high unused-code ratio — tree-shaking and route-splitting recover the wasted bytes.
Source: web.dev
82% of a.pub.network's code is unused. The script may be loading features you don't use.
Why this matters
Bundle has high unused-code ratio — tree-shaking and route-splitting recover the wasted bytes.