Updated 9 September 2026 · 3 min read
Quick answer: Improve Core Web Vitals by identifying what delays the main content, slows interactions or moves the layout unexpectedly. In a Webflow project, review large images, third-party scripts and components that change size while loading. Measure before and after each change, and use real-user data where it is available.
What are the Core Web Vitals targets?
Google’s web.dev documentation defines three good-experience thresholds: Largest Contentful Paint (LCP) at 2.5 seconds or less, Interaction to Next Paint (INP) at 200 milliseconds or less and Cumulative Layout Shift (CLS) at 0.1 or less. Assessment uses the 75th percentile of visits, considered separately for mobile and desktop. See the official Web Vitals guide.
LCP concerns the main visible content loading, INP concerns responsiveness to interaction and CLS concerns visual stability. A single overall score can hide which of those experiences needs attention.
How should you start a performance review?
Select representative pages: the homepage, a service page, an article and any page with substantial interactive features. Record the date, device category, URL and reported issue. Include the business task affected, such as waiting for a service image or trying to open the menu.
Real-user measurements and controlled tests answer different questions. The Web Vitals guide distinguishes field data from lab diagnostics; Lighthouse cannot directly measure INP during a normal page-load test. Use lab findings to investigate and field data to understand the experience across actual visits.
What should you investigate for slow loading?
- The main image: inspect its dimensions, file weight and how soon it is requested. Do not assume the largest file is always the LCP element; check the report.
- Competing resources: list videos, fonts and scripts requested early in the page.
- Repeated assets: check whether oversized images are used where a smaller responsive version would be sufficient.
Make one targeted change and retest. A good investigation names the element and the reason it is slow. “Compress everything” is less useful when the real delay comes from how the main content is discovered or displayed.
What should you investigate for slow interactions or layout shifts?
For interaction delays, reproduce the slow action and inspect the work happening at that time. Review optional embeds, chat tools and custom scripts with the person responsible for implementation. Remove a feature only after checking its business purpose and dependencies.
For layout shifts, watch the page load and note which element moves. Check whether images, videos and embedded content reserve appropriate space. Also inspect late notices or content inserted above material that visitors are already reading. The goal is a stable task flow, not simply a better screenshot.
Frequently asked questions
Does using Webflow guarantee good performance?
No. The finished page depends on its assets, content, interactions and external services as well as its platform. Evaluate the published implementation.
Should every page receive a perfect lab score?
A score is a diagnostic aid. Prioritize the issues that affect visitors, validate fixes and document trade-offs. An isolated perfect test does not establish that every visitor has a good experience.
Use the redesign launch checklist to include performance in a release plan, or discuss your website with Stefano Marketing Agency.
