Web Performance Metrics Cheat Sheet

Last Updated: November 21, 2025

Metric Breakdown

Metric Goal
FCP Render first text/image (<2s)
LCP Largest element paint (<2.5s)
CLS Avoid layout shifts (<0.1)

Optimization Commands

preload fonts/images
Prioritize critical assets
compress assets
Brotli/gzip static files
use IntersectionObserver
Defer offscreen loads

Monitoring

Collect RUM data, run Lighthouse audits, and keep budgets for bundle size + TBT.

💡 Pro Tip: Monitor lab + field data, focus on LCP/CLS first, and prefer preloading for critical assets.
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