Suggest an editImprove this articleRefine the answer for “What is a performance budget?”. Your changes go to moderation before they’re published.Approval requiredContentWhat you’re changing🇺🇸EN🇺🇦UAPreviewTitle (EN)Short answer (EN)**Performance budget** is a pre-set limit on the "weight" and load time of a site's key resources, meant to prevent performance from degrading. **Key point:** a performance budget is like a diet for a site: strict, measurable limits that keep it from becoming slow, heavy, and sluggish.Shown above the full answer for quick recall.Answer (EN)Image**Performance budget** is a pre-set limit on the "weight" and load time of a site's key resources, meant to prevent performance from degrading. --- ## What a performance budget can limit - the total page weight (for example, ≤ 170 KB for mobile) - the JS/CSS size (for example, JS ≤ 150 KB, CSS ≤ 50 KB) - the number of HTTP requests - load time (for example, TTI ≤ 3 s, LCP ≤ 2.5 s) - Web Vitals (LCP, FID, CLS) - the number of fonts, images, third-party scripts --- ## Example The team is told: - no more than 100 KB of JS - LCP no longer than 2.5 seconds - FID < 100 ms If these limits are exceeded, the build fails or is produced with a warning. --- ## Why this is needed - keeps the site from "bloating" as it grows - makes performance part of CI/CD - keeps UX fast through any changes - simplifies communication between designers, frontend, and managers: everyone works from the same numbers --- ## Conclusion A performance budget is like a diet for a site: strict, measurable limits that keep it from becoming slow, heavy, and sluggish.For the reviewerNote to the moderator (optional)Visible only to the moderator. Helps review go faster.