How do I improve INP scores on a WordPress site?

Key improvements are: reduce JavaScript bundle size by auditing and removing unused scripts, defer non-critical JavaScript so the main thread is available sooner, break up long tasks into smaller chunks using web workers or scheduler API, switch from heavy page builders (Divi, WPBakery) to lighter alternatives (Bricks, Gutenberg), and improve TTFB through better hosting so JavaScript is delivered faster. Server-side: Brotli compression, HTTP/3, and edge caching all reduce JavaScript delivery time.

INP (Interaction to Next Paint) in 2026 -- WP Pro Host

Q: What is Interaction to Next Paint (INP)?

Interaction to Next Paint (INP) is a Core Web Vital that measures the latency of every user interaction on a page — clicks, taps, and key presses — throughout the entire page lifecycle, reporting the worst-performing one. It replaced First Input Delay (FID) as a Core Web Vital in March 2024. Google's threshold for 'good' INP is under 150ms in 2026 (down from 200ms). Unlike FID, which only measured the delay before processing began, INP measures the full time from interaction to the next visual update.

Q: What is the difference between FID and INP?

First Input Delay (FID) measured only the delay before the browser started processing the very first user interaction after page load. Interaction to Next Paint (INP) measures the full visual response latency of every interaction throughout the entire page lifecycle and reports the worst one. INP is a much stricter and more representative metric — sites that passed FID comfortably can fail INP because INP captures slow interactions that occur after the page has fully loaded, such as opening a dropdown menu or submitting a form.

Interaction to Next Paint (INP) replaced First Input Delay (FID) as a Core Web Vital in March 2024. While FID only measured the delay before the browser started processing the first interaction, INP measures the full latency of every interaction throughout the page lifecycle — clicks, taps, and key presses — and reports the worst one.

The result: sites that passed FID comfortably are failing INP. Google’s data shows that roughly 65% of UK WordPress sites currently fail INP thresholds (above 200ms). The most common culprits are heavy JavaScript from page builders (Elementor, Divi, WPBakery), analytics scripts, and third-party embeds that block the main thread.

Hosting affects INP more than most site owners realise. A fast server response time gives the browser more time budget for JavaScript execution. If your TTFB is 800ms on shared hosting, the browser has far less headroom for processing interactions within the 200ms INP threshold. Cutting TTFB to 100ms with managed hosting gives JavaScript an extra 700ms of breathing room.

Server-level interventions that improve INP: HTTP/2 push for critical JavaScript, efficient compression (Brotli over Gzip) that reduces transfer size by 15-20%, edge-cached pages that eliminate origin round trips, and server-side rendering where possible to reduce client-side work. These are hosting decisions, not theme decisions.

WP Pro Host infrastructure

Optimised for INP performance: sub-100ms TTFB across all plans, Brotli compression on all responses, HTTP/2 with server push for critical resources, and CDN edge caching that eliminates origin latency. Combined with our built-in performance monitoring that flags INP regressions, your site stays within Google’s thresholds. Compare hosting options.

Frequently Asked Questions

What is Interaction to Next Paint (INP)?

INP is a Core Web Vital measuring the latency of every user interaction on a page — clicks, taps, and key presses — throughout the entire page lifecycle, reporting the worst-performing one. It replaced FID as a Core Web Vital in March 2024. Google’s threshold for ‘good’ INP is under 150ms in 2026. Unlike FID, which measured delay before processing began, INP measures the full time from interaction to the next visual update.

Why do WordPress sites fail INP?

The most common causes are heavy JavaScript from page builders (Elementor, Divi, WPBakery), third-party analytics and marketing scripts competing for CPU time, and insufficient server response time that delays JavaScript delivery. Roughly 65% of UK WordPress sites currently fail INP thresholds, primarily due to page builder JavaScript overhead combined with shared hosting that increases TTFB.

How does hosting affect INP scores?

Hosting affects INP indirectly through TTFB. A fast server response delivers JavaScript sooner, giving the browser more time budget within the 150ms threshold. If TTFB is 800ms on shared hosting, the browser has significantly less headroom for JavaScript execution. Server improvements that help INP include HTTP/3 connection multiplexing, Brotli compression reducing JavaScript payload size by 15–20%, and edge-cached pages eliminating origin round trips.

What is the difference between FID and INP?

FID measured only the delay before the browser started processing the first user interaction after page load. INP measures the full visual response latency of every interaction throughout the entire page lifecycle and reports the worst one. INP is a much stricter metric — sites that passed FID comfortably can fail INP because it captures slow interactions that occur after the page has fully loaded.

How do I improve INP on a WordPress site?

Key improvements: reduce JavaScript bundle size by auditing and removing unused scripts, defer non-critical JavaScript, switch from heavy page builders to lighter alternatives (Bricks, Gutenberg), and improve TTFB through better hosting. Server-side: Brotli compression, HTTP/3, and edge caching all reduce JavaScript delivery time.