A slow site equals lost revenue. Google data shows that 53% of mobile users abandon sites that take more than three seconds to load. Page speed doesn’t just impact user experience: slower sites have higher bounce rates, which means lower rankings, causing lower conversions and, ultimately, a domino effect. The best web designers know this and bake performance into every decision, from layout to asset selection.
1. Design Within a Performance Budget
High-performing sites are built with performance constraints in mind. A performance budget sets limits on page weight (in kilobytes), number of requests, and load time targets. Web designers who follow a performance budget make trade-offs early: layouts that can work with lighter images, web-safe fonts instead of external libraries, or SVGs in place of heavy PNG files.
For example, a designer working on an ecommerce homepage might cap total image weight at 500KB, enforce a two-font limit, and ensure hero content loads in under 2 seconds on 3G. Every decision during design is made with that in mind, which dramatically reduces rework in development and post-launch.
2. Use Real Performance Tools During Design
The best web designers leverage performance tools like WebPageTest and PageSpeed Insights to inform their layout and media decisions. WebPageTest allows for testing from various global locations and connection speeds, while PageSpeed Insights offers core web vitals based on real user performance data from the Chrome User Experience Report (CrUX). By regularly testing prototypes or staging environments, designers can identify and address issues such as cumulative layout shifts (CLS), first input delays (FID), or largest content paint (LCP) before development begins. For instance, a designer can significantly impact LCP by adjusting image layouts to ensure below-the-fold elements load efficiently.
3. Reduce Dependency on Large Media Files
Images are often the heaviest part of a page. The Web Almanac reports that images make up over 49% – 75% of total page weight on average. The most effective designers start with mobile-first image sets, use WebP or AVIF formats, and predefine image breakpoints with the srcset attribute to prevent oversized or jumbled delivery on small screens.
Best web designers also avoid decorative images that serve no functional purpose. Removing unnecessary banners and background textures, for example, can improve both page load and accessibility.
4. Font Loading Is a Technical Decision
Fonts are visual choices with technical consequences. They add to page load times and can cause unintended visible text. Font weight or style can add an additional 70KB, and external font loading introduces render-blocking behavior unless properly managed. Web.dev recommends using font-display: swap to avoid a flash of invisible text (FOIT) during load and preloading.
Designers who understand these trade-offs avoid using four or five font weights for a single typeface. They limit total font families to one or two, rely on system fonts for body text when branding allows, and preload headings or logos that must render immediately. This avoids layout shifts and improves First Contentful Paint (FCP).
5. Avoid Layouts That Cause Shifts or Blocking
Unstable layout harms usability and SEO. The best web designers assess the dimensions of their images, ads, embeds, fonts, and other aspects of the layout using the Cumulative Layout Shift (CLS). Designers can include placeholders or min-height rules to prevent layout jumps.
Animations should also be tested. When a designer includes scroll-based animation libraries such as Lottie or GSAP, these should be reviewed on low-end mobile hardware to determine their impact on task delays and interaction lags.
6. Collaborate Directly With Developers
Designers who collaborate with developers often catch performance issues early. For example, a Figma mockup might appear to load instantly, but the front-end version stalls because a third-party script loads before the hero image. Without hands-on coordination, fixes often come too late. Joint reviews of Lighthouse reports and pair testing on multiple devices ensure the design translates into fast, smooth experiences.
7. Validate With Real User Behavior
User-centric performance metrics matter more than theoretical load times. Tools such as Chrome UX Report (CrUX) and Real User Monitoring (RUM) help designers see how layout and content changes perform for actual users. Designers who check RUM data can identify if LCP increased after adding a background video, or if a new font caused CLS to spike.
Conclusion
Fast websites aren’t just coded well: they’re designed well from the start. Best web designers who prioritize page speed make better visual decisions, collaborate more closely with developers, and rely on measurable user data, not just aesthetic judgment. They understand that a 300ms delay can cut conversions, and that performance is part of the product.
Looking for agencies that specialize in high-performance designs? Browse our list of the best web design agencies.