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.
868 ms
Largest Contentful Paint Largest Contentful Paint — how long until the largest visible element loads. Under 2.5s is good.
2.96 s
Total Blocking Time Total Blocking Time — total time the main thread was blocked, preventing user input. Under 200ms is good.
104 ms
Cumulative Layout Shift Cumulative Layout Shift — measures visual stability. How much the page layout shifts during loading. Under 0.1 is good.
0.012
Speed Index Speed Index — how quickly content is visually displayed during load. Under 3.4s is good.
1.70 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.
2.98 s
Page Load Progression
DThird-Party ImpactAction100% third-party, 0 ms blockingFIX
DJS BundlesAction25 scripts, 321 KB unusedFIX
Downloaded but never executed on this page.
| Script | Size | Unused | Minified | Party |
|---|---|---|---|---|
| https://www.ultimate-guitar.com/static/public/build/ug_react_i18n_es6/202604/ug.e0dd23f705d9c000f4fdadaa26582812.js | 221 KB | 83 KB (38%) | ✓ | 3rd |
| https://accounts.google.com/gsi/client | 96 KB | 72 KB (75%) | ✓ | 3rd |
| https://cmp.inmobi.com/tcfv2/cmp2.js?referer=www.ultimate-guitar.com | 133 KB | 67 KB (51%) | ✓ | 3rd |
| https://cmp.inmobi.com/tcfv2/61/cmp2ui-en.js | 125 KB | 60 KB (48%) | ✓ | 3rd |
| https://www.ultimate-guitar.com/static/public/build/ug_react_i18n_es6/202604/4192.b8bbab426e89c3f5195381183ae28cf4.js | 104 KB | 39 KB (38%) | ✓ | 3rd |
| https://cmp.inmobi.com/choice/nrG7xD8rpA-hG/www.ultimate-guitar.com/choice.js?tag_version=V3 | 2 KB | — | ✓ | 3rd |
| https://www.ultimate-guitar.com/static/public/build/ug_react_i18n_es6/202604/9476.a114db79cd49187063948657c9e73343.js | 5 KB | — | ✓ | 3rd |
| https://www.ultimate-guitar.com/static/public/build/ug_react_i18n_es6/202604/9572.f11334f12aa79c35db2a5b1fc7d6ed14.js | 5 KB | — | ✓ | 3rd |
| https://www.ultimate-guitar.com/static/public/build/ug_react_i18n_es6/202604/8659.4f3b6df3bdf0d5e83bc7285f5be63992.js | 6 KB | — | ✓ | 3rd |
| https://www.ultimate-guitar.com/static/public/build/ug_react_i18n_es6/202604/9997.26324a8b9b1fc25a75200dcddb44c2dc.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
DPage Weight InventoryAction116 resources · 1.6 MB · 321 KB savings availableFIX
~321.3 KiB of savings available
| # | Resource | Type | Size | Cache | Unused | 3rd party | Issues |
|---|---|---|---|---|---|---|---|
| — | — | ||||||
| 116 resources | 1.6 MiB | ||||||
FHTTP CachingActionNo cache headersFIX
No Cache-Control header
Adding a Cache-Control header can significantly improve repeat-visit performance.
CPage Weight BudgetAction1.6 MB transferred, 116 requestsREVIEW
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
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
CImage OptimizationAction63 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
CJS Execution CostAction1605ms total JS executionREVIEW
Main Thread Breakdown
| Script | Total | Scripting | Parse/Compile | Party |
|---|---|---|---|---|
| https://www.ultimate-guitar.com/ | 569ms | 14ms | 1ms | 3rd |
| https://www.ultimate-guitar.com/static/public/build/ug_react_i18n_es6/202604/4192.b8bbab426e89c3f5195381183ae28cf4.js | 389ms | 327ms | 8ms | 3rd |
| https://www.ultimate-guitar.com/static/public/build/ug_react_i18n_es6/202604/ug.e0dd23f705d9c000f4fdadaa26582812.js | 186ms | 165ms | 13ms | 3rd |
| https://cmp.inmobi.com/tcfv2/cmp2.js?referer=www.ultimate-guitar.com | 139ms | 88ms | 10ms | 3rd |
| https://cmp.inmobi.com/tcfv2/61/cmp2ui-en.js | 117ms | 73ms | 10ms | 3rd |
| Unattributable | 115ms | 5ms | 0ms | 3rd |
| https://www.ultimate-guitar.com/static/public/build/ug_react_i18n_es6/202604/vendor.caa31f061717554bb5992e2c8a31251b.js | 92ms | 55ms | 2ms | 3rd |
A+Text CompressionAll text resources are compressedPASS
A+Font Loading4 fonts (206 KB)PASS
Web fonts
4
206 KB total
Render-blocking
0
of 4
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
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 ~57 KB and ~114 ms
A+Resource CachingAll resources properly cachedPASS
A+Critical Rendering PathNo render-blocking resourcesPASS
A+Resource HintsNo optimization neededPASS
A+Green HostingWhether the site is served from green-energy infrastructurePASS
Green Hosting
This site is hosted on green energy infrastructure
Provider: Cloudflare
Network Waterfall116 requests over 2362msINFO
Third-Party Script CostPer-script blocking time, transfer cost, and cache headersINFO
| Script | Category | Execution | Transfer | Unused | Monthly Cost | Verdict |
|---|---|---|---|---|---|---|
www.ultimate-guitar.com www.ultimate-guitar.com | Other | 569ms | 28 KB | — | $8/mo | Costly |
www.ultimate-guitar.com www.ultimate-guitar.com | Other | 389ms | 104 KB | 38% | $5/mo | Costly |
www.ultimate-guitar.com www.ultimate-guitar.com | Other | 186ms | 221 KB | 38% | $2/mo | Optional |
cmp.inmobi.com cmp.inmobi.com | Other | 139ms | 133 KB | 51% | $2/mo | Optional |
cmp.inmobi.com cmp.inmobi.com | Other | 117ms | 125 KB | 48% | $2/mo | Optional |
Unattributable Unattributable | Other | 115ms | 0 KB | — | $2/mo | Optional |
www.ultimate-guitar.com www.ultimate-guitar.com | Other | 92ms | 34 KB | — | $1/mo | Optional |
These scripts may cost more than they're worth
- www.ultimate-guitar.com adds 569ms and costs ~$8/month
- www.ultimate-guitar.com adds 389ms and costs ~$5/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.ultimate-guitar.com takes 569ms 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.ultimate-guitar.com takes 389ms 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
51% of cmp.inmobi.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