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Performance

· 14 checks — Lighthouse + waterfall + sustainability rolled into one auditable list.
SCORE
85
GRADE
B
FIX
1
REVIEW
3
PASS
8
INFO
2

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

Mobile Desktop
53
Performance Overall performance score (0–100) based on Core Web Vitals and other metrics. 90+ is good.
88
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.
92
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.

2.33 s

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

4.07 s

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

0 ms

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

0.256

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

2.33 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.

4.07 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
14
8 PASS 3 REVIEW 1 FIX
F
Page Weight Budget
Action
2.9 MB transferred, 59 requests
FIX
2.9 MB transferred, 59 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::
59 HTTP requests
Info::
Estimated 0.61 g CO2 per page load
2.9 MB / 2.4 MB budget
2.9 MB transferred
59 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 126.3 KiB 4%
Other 2.0 KiB 0%
Other 732 B 0%
Other 361 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
12 images, 0 KB saveable
REVIEW
12 images, 0 KB saveable
Info::
All images are well-optimized
12 images 1.1 MB
0 oversized -0 KB
9 legacy format
0 missing dimensions CLS risk
C
JS Bundles
Action
22 scripts, 117 KB unused
REVIEW
22 scripts, 117 KB unused
Warning::
https://www.mcgill.ca/root/js/js_G8UCeLS2V3_kmKnBU...: 44 KB unused (36%)
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_UnUAFCNTGurRKyhNy...: 24 KB unused (85%)
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
Warning::
https://www.mcgill.ca/root/js/js_NLLXow_P0hT3RGJwt...: 24 KB unused (58%)
Consider code splitting or tree shaking to reduce unused code.
Info::
Total unused JavaScript: 117 KB
117 KB unused JavaScript

Downloaded but never executed on this page.

ScriptSizeUnusedMinifiedParty
https://www.mcgill.ca/root/js/js_G8UCeLS2V3_kmKnBUDyyePWz6JTaxtx9x2_FgJzC_Cs.js125 KB44 KB (36%)✗1st
https://www.mcgill.ca/sites/all/themes/coltrane19/dist/videoModalComponent.6edef453.js36 KB25 KB (70%)✓1st
https://www.mcgill.ca/root/js/js_UnUAFCNTGurRKyhNy7N72Mv86IdtFGAwSpI4omffLWM.js29 KB24 KB (85%)✗1st
https://www.mcgill.ca/root/js/js_NLLXow_P0hT3RGJwt-tDxP0HFx4QVqYa_W5YKdBxYuQ.js42 KB24 KB (58%)✓1st
https://www.youtube.com/s/_/ytembeds/_/js/k=ytembeds.base.en_US.I-saIP3mOa8.2021.O/am=AAAABQ/d=1/exm=base,root/ed=1/br=1/rs=AGKMywGgGTExJs4NRA0c5nPXigdlDVJxcA/m=r78Drb130 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+
JS Execution Cost
427ms total JS execution
PASS
427ms total JS execution
Info::
https://www.mcgill.ca/: 185ms CPU time
Info::
https://www.mcgill.ca/root/js/js_G8UCeLS2V3_kmKnBU...: 151ms CPU time
Info::
Unattributable: 91ms CPU time
Info::
Third-party scripts: 91ms (21% of total)

Main Thread Breakdown

Other 29% Style & Layout 25% Script Evaluation 22% Rendering 14% Parse HTML & CSS 7% Script Parsing & Compilation 3%
ScriptTotalScriptingParse/CompileParty
https://www.mcgill.ca/185ms2ms2ms1st
https://www.mcgill.ca/root/js/js_G8UCeLS2V3_kmKnBUDyyePWz6JTaxtx9x2_FgJzC_Cs.js151ms76ms3ms1st
Unattributable91ms1ms0ms3rd
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 1.0 s 2.0 s 3.0 s 4.0 s FCP 2.3 s LCP 4.1 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/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://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://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
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
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
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+
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
59 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
21% of JavaScript execution is third-party
First-party Third-party 91ms · 0KB · CA$1/mo
Unattributable
Other
Optional
Execution 91ms
Transfer 0 KB
Monthly Cost CA$1/mo

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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