Performance
· 17 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.
2.86 s
Largest Contentful Paint Largest Contentful Paint — how long until the largest visible element loads. Under 2.5s is good.
3.73 s
Total Blocking Time Total Blocking Time — total time the main thread was blocked, preventing user input. Under 200ms is good.
120 ms
Cumulative Layout Shift Cumulative Layout Shift — measures visual stability. How much the page layout shifts during loading. Under 0.1 is good.
0.030
Speed Index Speed Index — how quickly content is visually displayed during load. Under 3.4s is good.
4.19 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.
6.94 s
Page Load Progression
389 ms
777 ms 1.2 s 1.6 s 1.9 s
2.3 s
2.7 s
3.1 sDThird-Party ImpactAction100% third-party, 0 ms blockingFIX
BPage Weight Budget1.1 MB transferred, 29 requestsREVIEW
CJS Execution CostAction1107ms total JS executionREVIEW
Main Thread Breakdown
| Script | Total | Scripting | Parse/Compile | Party |
|---|---|---|---|---|
| https://www.kth.se/ | 445ms | 27ms | 8ms | 3rd |
| Unattributable | 279ms | 15ms | 0ms | 3rd |
| https://www.kth.se/js/core-82a01db45b4ca0cb6c8e8d2d67aa3f6e.js | 160ms | 117ms | 42ms | 3rd |
| https://analytics-stat.sys.kth.se/kth/matomo/js/container_vsVPCyVy.js | 151ms | 105ms | 44ms | 3rd |
| https://www.kth.se/css/kth-f6919e425a1c60964fdc47d8362288d0.css | 72ms | 0ms | 0ms | 3rd |
BJS Bundles5 scripts, 115 KB unusedREVIEW
Downloaded but never executed on this page.
| Script | Size | Unused | Minified | Party |
|---|---|---|---|---|
| https://analytics-stat.sys.kth.se/kth/matomo/js/container_vsVPCyVy.js | 307 KB | 60 KB (19%) | ✓ | 3rd |
| https://www.kth.se/js/core-82a01db45b4ca0cb6c8e8d2d67aa3f6e.js | 100 KB | 55 KB (55%) | ✓ | 3rd |
| https://app.kth.se/kpm/kpm.js | 2 KB | — | ✓ | 3rd |
| https://www.kth.se/js/block/mega-menu-style10-044b68d8039254ab9d94bd0ea99e7c94.js | 1 KB | — | ✓ | 3rd |
| https://www.kth.se/js/block/search-block-cc59975a43b71990cde4d6c84635022d.js | 1 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
BPage Weight Inventory29 resources · 1.1 MB · 115 KB savings availableREVIEW
~114.9 KiB of savings available
| # | Resource | Type | Size | Cache | Unused | 3rd party | Issues |
|---|---|---|---|---|---|---|---|
| — | — | ||||||
| 29 resources | 1.1 MiB | ||||||
CGreen HostingActionWhether the site is served from green-energy infrastructureREVIEW
Green Hosting
No green hosting detected
BHTTP Cachingno-cacheREVIEW
no-cache
| Directive | Value | Meaning |
|---|---|---|
| no-cache | — | Cache but always revalidate first |
A+Text CompressionAll text resources are compressedPASS
A+Image Optimization13 images, 0 KB saveablePASS
A+Font Loading2 fonts (55 KB)PASS
Web fonts
2
55 KB total
Render-blocking
0
of 2
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
A+Render-Blocking ResourcesNo render-blocking resources detectedPASS
A+Third-Party ResourcesNo third-party resources detectedPASS
Network Waterfall29 requests over 5297msINFO
Third-Party Script CostPer-script blocking time, transfer cost, and cache headersINFO
| Script | Category | Execution | Transfer | Unused | Monthly Cost | Verdict |
|---|---|---|---|---|---|---|
www.kth.se www.kth.se | Other | 445ms | 17 KB | — | kr48/mo | Costly |
Unattributable Unattributable | Other | 279ms | 0 KB | — | kr30/mo | Costly |
www.kth.se www.kth.se | Other | 160ms | 100 KB | 55% | kr17/mo | Optional |
analytics-stat.sys.kth.se analytics-stat.sys.kth.se | Other | 151ms | 307 KB | 19% | kr16/mo | Optional |
www.kth.se www.kth.se | Other | 72ms | 75 KB | — | kr8/mo | Optional |
These scripts may cost more than they're worth
- www.kth.se adds 445ms and costs ~kr48/month
- Unattributable adds 279ms and costs ~kr30/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.kth.se takes 445ms 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 279ms 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
55% of www.kth.se'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