Free SEO tool
Page Speed Budget Calculator
Set a total page weight budget and allocate it across resource types. See estimated load times, Core Web Vitals targets, and warnings when categories exceed recommended limits.
Budget Presets
Budget Allocation
Visual Breakdown
Estimated Load Times
Core Web Vitals Estimate
Performance Budget Best Practices
Why Performance Budgets Matter
A performance budget sets hard limits on page weight and resource counts. Without one, pages gradually bloat from third-party scripts, uncompressed images, and framework upgrades. Google uses Core Web Vitals as a ranking signal, and every 100ms of added load time reduces conversions by roughly 1%.
JavaScript Is the Most Expensive Resource
Byte-for-byte, JavaScript costs more than any other resource type because the browser must download, parse, compile, and execute it. Aim for under 100KB of JS total (compressed). Every KB of JS delays interactivity far more than 1KB of images or CSS.
Core Web Vitals Thresholds
LCP (Largest Contentful Paint): under 2.5s for "good." CLS (Cumulative Layout Shift): under 0.1 for "good." INP (Interaction to Next Paint): under 200ms for "good." These are the 75th percentile field values Google uses in ranking.
Image Optimization Has the Highest ROI
Images typically account for 50-70% of total page weight. Converting to WebP or AVIF, serving responsive sizes via srcset, and lazy-loading below-the-fold images can cut total transfer size by 40-60% with no visual quality loss.
Font Loading Strategy
Self-host fonts in WOFF2 format, preload the critical font file, and use font-display: swap to prevent invisible text. Subset fonts to only the characters you need. A full Google Fonts family can be 80KB+; subsetting can reduce it to 15-20KB.