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https://www.mcgill.ca

Performance

· 16 checks — Lighthouse + waterfall + sustainability rolled into one auditable list.
SCORE
85
GRADE
B
FIX
1
REVIEW
4
PASS
9
INFO
2

Performance-focused optimization plan with CWV assessment, top offenders, and time estimates

Mobile Desktop
46
Performance Overall performance score (0–100) based on Core Web Vitals and other metrics. 90+ is good.
81
Accessibility Measures how accessible the page is for users with disabilities. Checks color contrast, ARIA labels, and semantic HTML.
96
Best Practices Checks for modern web development best practices including HTTPS, no console errors, and secure JavaScript.
85
SEO Measures basic SEO optimizations: meta tags, crawlability, link text, and mobile friendliness.

First Contentful Paint First Contentful Paint — how long until the browser renders the first piece of content. Under 1.8s is good.

11.45 s

Largest Contentful Paint Largest Contentful Paint — how long until the largest visible element loads. Under 2.5s is good.

20.08 s

Total Blocking Time Total Blocking Time — total time the main thread was blocked, preventing user input. Under 200ms is good.

22 ms

Cumulative Layout Shift Cumulative Layout Shift — measures visual stability. How much the page layout shifts during loading. Under 0.1 is good.

0.203

Speed Index Speed Index — how quickly content is visually displayed during load. Under 3.4s is good.

11.45 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.

20.08 s

Page Load Progression

375 ms
750 ms
1.1 s
1.5 s
1.9 s
2.2 s
2.6 s
3.0 s
Checks
16
9 PASS 4 REVIEW 1 FIX
F
Page Weight Budget
Action
2.9 MB transferred, 55 requests
FIX
2.9 MB transferred, 55 requests
Warning::
Page weighs 9.1 MB (2.9 MB transferred)
Warning::
Images are 1.1 MB — compress or use modern formats
Convert images to WebP/AVIF and resize to display dimensions to reduce transfer size.
Got: 1.1 MB
Warning::
JavaScript is 1.1 MB — consider code splitting or lazy loading
Large JavaScript bundles delay interactivity. Split code by route or defer non-critical scripts.
Got: 1.1 MB
Info::
CSS is 487 KB — consider purging unused styles
Remove unused CSS rules with tools like PurgeCSS to reduce stylesheet size.
Got: 487 KB
Info::
55 HTTP requests
Info::
Estimated 0.61 g CO2 per page load
2.9 MB / 2.4 MB budget
2.9 MB transferred
55 requests
0.61 g CO2 per page load
Images 1.1 MiB 38%
JavaScript 1.1 MiB 37%
CSS 486.7 KiB 16%
Fonts 136.0 KiB 5%
HTML 125.9 KiB 4%
Other 2.0 KiB 0%
Other 732 B 0%
Other 311 B 0%
Other 0 B 0%
0 2.4 MB 4.9 MB
Over budget

Convert images to WebP/AVIF and resize to display dimensions to reduce transfer size.

Why this matters

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.

Why this matters

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.

Why this matters

CSS bundle is large — purge unused styles (PurgeCSS, Tailwind JIT) to reduce CSS payload.

Source: web.dev

B
Image Optimization
11 images, 0 KB saveable
REVIEW
11 images, 0 KB saveable
Info::
All images are well-optimized
11 images 1.1 MB
0 oversized -0 KB
8 legacy format
0 missing dimensions CLS risk
B
JS Execution Cost
877ms total JS execution
REVIEW
877ms total JS execution
Warning::
https://www.mcgill.ca/: 302ms CPU time
Warning::
Unattributable: 291ms CPU time
Info::
https://www.mcgill.ca/root/js/js_G8UCeLS2V3_kmKnBU...: 213ms CPU time
Info::
https://www.mcgill.ca/sites/all/themes/coltrane19/...: 70ms CPU time
Info::
Third-party scripts: 291ms (33% of total)

Main Thread Breakdown

Other 32% Script Evaluation 27% Style & Layout 26% Parse HTML & CSS 8% Script Parsing & Compilation 4%
ScriptTotalScriptingParse/CompileParty
https://www.mcgill.ca/302ms5ms4ms1st
Unattributable291ms5ms0ms3rd
https://www.mcgill.ca/root/js/js_G8UCeLS2V3_kmKnBUDyyePWz6JTaxtx9x2_FgJzC_Cs.js213ms142ms11ms1st
https://www.mcgill.ca/sites/all/themes/coltrane19/dist/videoModalComponent.6edef453.js70ms67ms3ms1st
C
JS Bundles
Action
22 scripts, 115 KB unused
REVIEW
22 scripts, 115 KB unused
Warning::
https://www.mcgill.ca/root/js/js_G8UCeLS2V3_kmKnBU...: 43 KB unused (35%)
Consider code splitting or tree shaking to reduce unused code.
Warning::
https://www.mcgill.ca/root/js/js_G8UCeLS2V3_kmKnBU...: unminified — 28 KB could be saved
Warning::
https://www.mcgill.ca/sites/all/themes/coltrane19/...: 25 KB unused (70%)
Consider code splitting or tree shaking to reduce unused code.
Warning::
https://www.mcgill.ca/root/js/js_NLLXow_P0hT3RGJwt...: 24 KB unused (58%)
Consider code splitting or tree shaking to reduce unused code.
Warning::
https://www.mcgill.ca/root/js/js_UnUAFCNTGurRKyhNy...: 23 KB unused (81%)
Consider code splitting or tree shaking to reduce unused code.
Warning::
https://www.mcgill.ca/root/js/js_UnUAFCNTGurRKyhNy...: unminified — 10 KB could be saved
Info::
Total unused JavaScript: 115 KB
115 KB unused JavaScript

Downloaded but never executed on this page.

ScriptSizeUnusedMinifiedParty
https://www.mcgill.ca/root/js/js_G8UCeLS2V3_kmKnBUDyyePWz6JTaxtx9x2_FgJzC_Cs.js125 KB43 KB (35%)✗1st
https://www.mcgill.ca/sites/all/themes/coltrane19/dist/videoModalComponent.6edef453.js36 KB25 KB (70%)✓1st
https://www.mcgill.ca/root/js/js_NLLXow_P0hT3RGJwt-tDxP0HFx4QVqYa_W5YKdBxYuQ.js42 KB24 KB (58%)✓1st
https://www.mcgill.ca/root/js/js_UnUAFCNTGurRKyhNy7N72Mv86IdtFGAwSpI4omffLWM.js29 KB23 KB (81%)✗1st
https://www.youtube.com/s/_/ytembeds/_/js/k=ytembeds.base.en_US.I-saIP3mOa8.2021.O/am=AAAABQ/d=1/br=1/rs=AGKMywGgGTExJs4NRA0c5nPXigdlDVJxcA/m=root,base207 KB—✓3rd
https://www.mcgill.ca/sites/all/themes/coltrane19/dist/drupalYTPlayerAPI.aaa0ed5d.js2 KB—✓1st
https://www.mcgill.ca/root/js/js_N23fS6ooC-uvOJ2j7mtuBbVQeGAvoXnACb9oAiqrOPE.js9 KB—✗1st
https://www.mcgill.ca/root/js/js_SvFAI8iewe7Ipse2GW7N9TMIrfgiVPH7c090khnScTY.js13 KB—✗1st
https://www.mcgill.ca/sites/all/themes/coltrane19/dist/coltrane.js?td3xfi7 KB—✓1st
https://www.mcgill.ca/root/js/js_v7jDIMUEcN6BBNPa3HVRFvCSboKsSIXuOKzG8_3BWlc.js4 KB—✓1st

Consider code splitting or tree shaking to reduce unused code.

Why this matters

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.

Why this matters

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.

Why this matters

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.

Why this matters

This bundle has high unused code — code-split or tree-shake to ship only what executes.

Source: web.dev / Lighthouse coverage

C
Green Hosting
Action
Whether the site is served from green-energy infrastructure
REVIEW

Green Hosting

No green hosting detected

A
Third-Party Impact
35% third-party, 0 ms blocking
PASS
35% third-party, 0 ms blocking
Info::
Third-party code accounts for 35% of page weight (1.0 MiB of 2.9 MiB)
Info::
Third-party blocking time is low (0 ms)
65%
35%
First-party Third-party
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
6 fonts (136 KB)
PASS
6 fonts (136 KB)
Info::
6 font(s) use font-display: swap (FOUT risk but functional)

Web fonts

6

136 KB total

Render-blocking

0

of 6

Dominant font-display

swap

Most common across fonts

Font loading timeline
Transfer FOIT (block) FOUT (swap)
0 ms 2.0 s 4.0 s 6.0 s 8.0 s 10.0 s 12.0 s 14.0 s 16.0 s 18.0 s 20.0 s FCP 11.5 s LCP 20.1 shttps://fonts.gstatic.com/s/roboto/v48/KFO7CnqEu92Fr1ME7kSn66aGLdTylUAMa3yUBHMdazQ.woff2KFO7CnqEu92Fr1ME7kSn66a... https://fonts.gstatic.com/s/roboto/v48/KFO7CnqEu92Fr1ME7kSn66aGLdTylUAMa3yUBHMdazQ.woff2 — 33.9 KiB — 0 ms — font-display: swaphttps://www.mcgill.ca/sites/all/themes/coltrane19/dist/McGillSans-Regular.7ac71b20.woffMcGillSans-Regular.7ac7... https://www.mcgill.ca/sites/all/themes/coltrane19/dist/McGillSans-Regular.7ac71b20.woff — 17.8 KiB — 0 ms — font-display: swaphttps://www.mcgill.ca/sites/all/themes/coltrane19/dist/McGillSans-Medium.0097ee5d.woffMcGillSans-Medium.0097e... https://www.mcgill.ca/sites/all/themes/coltrane19/dist/McGillSans-Medium.0097ee5d.woff — 18.6 KiB — 0 ms — font-display: swaphttps://www.mcgill.ca/sites/all/themes/coltrane19/dist/line-awesome.8f27b776.woff2line-awesome.8f27b776.w... https://www.mcgill.ca/sites/all/themes/coltrane19/dist/line-awesome.8f27b776.woff2 — 44.9 KiB — 0 ms — font-display: swaphttps://www.mcgill.ca/sites/all/themes/coltrane19/dist/McGillSerif-Regular.2fe60a11.woffMcGillSerif-Regular.2fe... https://www.mcgill.ca/sites/all/themes/coltrane19/dist/McGillSerif-Regular.2fe60a11.woff — 20.8 KiB — 0 ms — font-display: swaphttps://fonts.gstatic.com/s/roboto/v48/KFO7CnqEu92Fr1ME7kSn66aGLdTylUAMa3yUBHMdazQ.woff2KFO7CnqEu92Fr1ME7kSn66a... https://fonts.gstatic.com/s/roboto/v48/KFO7CnqEu92Fr1ME7kSn66aGLdTylUAMa3yUBHMdazQ.woff2 — 0 B — 0 ms — font-display: swap
KFO7CnqEu92Fr1ME7kSn66a... woff2 swap
Size 34 KB
Load time 0 ms
Start 0 ms
Risk FOUT — text flashes from fallback to web font
McGillSans-Regular.7ac7... woff swap
Size 18 KB
Load time 0 ms
Start 0 ms
Risk FOUT — text flashes from fallback to web font
  • Convert to woff2 for ~30% smaller file size
McGillSans-Medium.0097e... woff swap
Size 19 KB
Load time 0 ms
Start 0 ms
Risk FOUT — text flashes from fallback to web font
  • Convert to woff2 for ~30% smaller file size
line-awesome.8f27b776.w... woff2 swap
Size 45 KB
Load time 0 ms
Start 0 ms
Risk FOUT — text flashes from fallback to web font
McGillSerif-Regular.2fe... woff swap
Size 21 KB
Load time 0 ms
Start 0 ms
Risk FOUT — text flashes from fallback to web font
  • Convert to woff2 for ~30% smaller file size
KFO7CnqEu92Fr1ME7kSn66a... woff2 swap
Size 0 KB
Load time 0 ms
Start 0 ms
Risk FOUT — 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)

Fixing the unchecked items could save ~17 KB and ~34 ms

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+
Render-Blocking Resources
No render-blocking resources detected
PASS
No render-blocking resources detected
Info::
No render-blocking resources detected in <head>
A+
Third-Party Resources
No third-party resources detected
PASS
No third-party resources detected
A+
HTTP Caching
max-age=21600 (6 hours)
PASS
max-age=21600 (6 hours)
Info::
Cache-Control header is set
Got: private, s-maxage=0, max-age=21600
Info::
Effective TTL: 6 hours (max-age=21600)
Info::
ETag present — enables conditional (304) responses
Info::
Last-Modified header present
Cache-Control

private, s-maxage=0, max-age=21600

DirectiveValueMeaning
private—Only browser cache, not CDN/proxy
s-maxage0CDN caches for 0 seconds
max-age21600Cache for 6 hours
Effective TTL: 21600 seconds
Network Waterfall
55 requests over 0ms
INFO

Performance analysis not available for this result.

Third-Party Script Cost
Per-script blocking time, transfer cost, and cache headers
INFO
33% of JavaScript execution is third-party
First-party Third-party 291ms · 0KB · CA$5/mo
Unattributable
Other
Costly
Execution 291ms
Transfer 0 KB
Monthly Cost CA$5/mo

These scripts may cost more than they're worth

  • Unattributable adds 291ms and costs ~CA$5/month

Unattributable takes 291ms 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

How third-party costs are calculated

All checks on this page are automated. Results are estimates - run targeted manual reviews when the score affects a release decision.

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