What is Performance Budget?
Turkish: Performans Bütçesi
A performance budget sets measurable limits for a web page, such as file size, request count, and loading time, before regressions ship.
What is a Performance Budget?
A performance budget is a set of agreed technical limits that keeps a page fast over time. Design, content, and development decisions are checked against those limits; when a new video, third-party script, or large image is added, the team asks whether the page still stays within target.
An example budget might say “homepage JavaScript must stay under 180 KB, total image weight under 900 KB, and LCP under 2.5 seconds.” Targets are usually defined separately for device class, network condition, and page type.
How It Is Applied
- Select critical pages: homepage, product detail, checkout step, or lead form.
- Choose metrics: total page weight, request count, JavaScript size, LCP, INP, or TTFB.
- Connect measurement: Lighthouse CI, WebPageTest, real-user monitoring, or build reports.
- React to breaches: warn the team or block release until the regression is addressed.
Business Use
A performance budget is especially useful for e-commerce pages that grow during campaigns, image-heavy corporate sites, and marketing pages with third-party tracking tags. Without a budget, speed work often becomes a one-time cleanup; with a budget, new changes stay inside a defined quality line.
Core Web Vitals targets and image optimization are among the most common parts of a performance budget.
Related Terms
Core Web Vitals are Google's field metrics for web experience, measuring loading speed, responsiveness, and visual stability.
Image OptimizationImage optimization makes pages load faster through correct sizing, modern formats, compression, responsive delivery, and loading strategy.
Intersection ObserverIntersection Observer is a browser API that asynchronously detects when an element enters or leaves the viewport or a chosen container.
Web FontA web font displays brand-specific typography through font files downloaded by the browser and must be loaded carefully.