How design affects each metric
| Metric | Design choices that hurt it | Design choices that help it |
|---|---|---|
| LCP, loading | Video heroes, sliders and huge photos | One optimized image or a strong text headline |
| INP, responsiveness | Chat widgets, animations and heavy builders | Few scripts and simple interactions |
| CLS, stability | Late banners, ads and images without set sizes | Reserved space for every image and notice |
Google's targets come from real visits. LCP should be 2.5 seconds or less, INP 200 milliseconds or less and CLS 0.1 or less.
Design decisions that cost the most
- Sliders and carousels. Several big images load for content few people see.
- Video backgrounds. Megabytes of video before the headline appears.
- Cookie and promo bars. They push content down when they appear late.
- Too many fonts. Each family and weight is another download.
- Animation on scroll. It can make taps feel slow on phones.
Design for speed from the first sketch
Speed is cheapest to get right at the design stage. A designer who knows the metrics plans a fast first screen and reserves space for every element. Third-party widgets stay to a minimum. Fixing a finished design costs much more.
Good example. A designer gives a clinic's homepage a bold headline over one compressed photo. The cookie notice has reserved space, and the slider is gone.
Bad example. A designer delivers a homepage with a full-screen video, a five-slide carousel and a pop-up. The developer can only make it slightly less slow.
Check before and after launch
Test design templates in PageSpeed Insights before launch, then watch the Core Web Vitals report in Search Console once real visits arrive.
Rathly.com passes all three metrics on mobile, and we design client sites to the same targets. See why websites load slowly, or ask our web design team for a speed review.