Core Web Vitals 2026: How to Improve Your INP Score
Core Web Vitals 2026: what INP is, how it's measured, and how to optimize it on WordPress sites. A practical guide.
What Are Core Web Vitals?
Core Web Vitals consist of three core metrics Google defined to measure the quality of a page's user experience: LCP for loading performance, INP for interaction responsiveness and CLS for visual stability. These metrics form the measurable core of Google's page experience signals.
LCP: Loading Performance
Largest Contentful Paint (LCP) measures the time until the largest content element in the viewport (usually a hero image or heading text) is rendered on screen. A good LCP value is under 2.5 seconds.
To improve LCP, reduce server response time, cut render-blocking resources, preload critical images and optimize images in modern formats. A slow server or unoptimized large images are the most common LCP problems.
INP: Interaction Responsiveness
Interaction to Next Paint (INP) measures how quickly the page provides a visual response to user interactions (clicks, taps, keyboard input). In March 2024 it replaced the FID metric as an official Core Web Vital. A good INP value is under 200 milliseconds.
Break up long tasks - Split JavaScript tasks that occupy the main thread for long stretches into smaller chunks.
Reduce unnecessary JS - Remove unused code and limit the impact of third-party scripts.
Defer rendering - Defer the render cost of off-screen content with techniques like content-visibility.
CLS: Visual Stability
Cumulative Layout Shift (CLS) measures the total impact of elements shifting unexpectedly while the page loads. A good CLS value is under 0.1. Setting size attributes on images and iframes, reserving space for ad slots and loading fonts stably all reduce CLS.
Field Data and Measurement
Core Web Vitals are measured with two kinds of data: lab data (a controlled environment like Lighthouse) and field data (real-user measurements). Google uses Chrome User Experience Report (CrUX) field data for ranking assessment. So base your optimization decisions on the field data in PageSpeed Insights and Search Console.