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INP: the Core Web Vital quietly killing WordPress sites

In March 2024, Google replaced First Input Delay with Interaction to Next Paint. 43% of websites fail it. WordPress sites are the biggest casualties.

April 18, 2026·5 min read·By Carey Davis

In March 2024, Google replaced First Input Delay with a new Core Web Vital called Interaction to Next Paint (INP). Most business owners in Orange County never heard. Their developers did not mention it. But it is a ranking signal now, and it is rougher than the metric it replaced.

200ms
The 'good' threshold for INP
43%
Of sites currently failing it
38%
WordPress sites passing CWV
58%
Next.js / framework sites passing

INP measures how long your site takes to respond after someone clicks, taps, or types — across the whole session, not just the first interaction. Under 200ms is good. Over 500ms is poor. And unlike the old First Input Delay metric, INP does not let you off the hook after the first click.

Why INP is harder than what it replaced

First Input Delay measured the wait between a user's first interaction and the browser starting to handle it. It was lenient. Most sites passed it without trying. INP measures every interaction across an entire visit and reports the worst of them.

That changes the math entirely. A site can feel fast on the homepage and fail INP because the contact form, the menu, or the gallery is sluggish on mobile.

Nearly half the sites on the public web are currently failing the new bar.
Chrome User Experience Report, early 2026

The platform problem

This is where Orange County small businesses get hit hardest. WordPress sites with heavy page builders (Elementor, Divi), bloated plugin stacks, and unoptimized third-party scripts are the biggest casualties.

Core Web Vitals pass rate by platform, 2026
Next.js / Astro / framework sites58%
Squarespace52%
Webflow49%
Shopify44%
WordPress38%
Wix33%

Source: Aggregated from 2026 Chrome User Experience Report public data

WordPress is at the bottom not because the platform is bad — WordPress can be fast — but because the average WordPress installation collects plugins like a winter coat collects lint. Each plugin adds JavaScript. Each script blocks the main thread. Each blocked thread degrades INP.

What 100ms actually costs

Performance research from Akamai and Google has consistently found that a 100ms delay in load time costs roughly 1% in conversions. For a business doing 100 leads a month, that is one less lead. For a business doing 10,000 visits, it scales up fast.

1%
Drop in conversions per 100ms of added load delay (industry-aggregated A/B data)
Akamai, Google, multiple e-commerce studies

INP failures usually live in the 300-800ms range, which means most failing sites are bleeding 3-7% of their conversions to delays the owner cannot see and the developer never measured.

How to check your INP today

Free, takes about 60 seconds.

  1. 1
    Run PageSpeed Insights

    Visit pagespeed.web.dev and paste your homepage URL. Make sure you check both Mobile and Desktop tabs.

  2. 2
    Look for the INP metric

    It is in the "Core Web Vitals Assessment" section near the top. Green means under 200ms. Yellow is 200-500ms. Red is over 500ms.

  3. 3
    Check field data, not just lab data

    Field data (real Chrome users) is more reliable than lab data (a single test run). If you do not have enough field data yet, run the test on a few key pages — homepage, contact page, services page — and look at lab numbers.

If your INP is red on mobile, you are in the failing 43%, and you are losing measurable conversions to it.

What actually fixes it

The fix is not always a rebuild. Sometimes it is auditing third-party scripts and killing the dead weight. Sometimes it is the platform choice itself.

If you are on WordPress

Audit your plugins ruthlessly. Most sites are running 30+ plugins where 8 are doing 90% of the work. Remove anything you have not consciously used in the last 6 months. Replace heavy page builders with native block themes if the rebuild is small enough to justify. Move analytics and tag managers to load asynchronously or via server-side tagging.

If you are on a custom or framework site

You probably do not have a platform problem — you have an asset problem. Oversized images, unoptimized fonts, blocking JavaScript. PageSpeed will tell you exactly which assets to fix.

If you are on Wix or Squarespace

You have less to optimize because the platform controls the rendering stack. Your fix is mostly content choices: fewer animations, smaller hero images, lighter embeds.

The bigger picture

Core Web Vitals are no longer a nice-to-have for SEO. They are a measurable lever on conversion rate, search ranking, and AI visibility. Sites that pass them get a small but real boost. Sites that fail get a small but real penalty. Compounded over 12-18 months of visits, that is not nothing.

If you have not checked your INP since March 2024, check it this week. The fix is usually smaller than you think — and the cost of ignoring it is bigger than you think.