If your web team has mentioned “Core Web Vitals” to you before, you probably nodded along and filed it under “technical stuff I trust them to handle.” That’s fair — but there’s a specific piece of this worth understanding in plain language, because it changed relatively recently and it affects both your search visibility and, more importantly, whether visitors stick around long enough to become customers.
The piece in question is called INP, and it’s the newest addition to Google’s Core Web Vitals.
What Core Web Vitals are, briefly
Core Web Vitals are a set of metrics Google uses to measure real-world user experience on a webpage — not just “does it load,” but “does it feel fast and responsive to an actual person using it.” They factor into search ranking, and more practically, they correlate strongly with whether visitors stay, browse, and convert, or bounce back to the search results in frustration.
For years, the three Core Web Vitals were Largest Contentful Paint (how fast the main content loads), Cumulative Layout Shift (whether things jump around annoyingly as the page loads), and First Input Delay (how quickly the page responds to your very first click or tap).
What changed: INP replaced First Input Delay
In March 2024, Google officially replaced First Input Delay with a new metric called Interaction to Next Paint (INP), and it’s a meaningfully better — and stricter — way of measuring responsiveness.
Here’s the difference in plain terms: First Input Delay only measured your site’s response to the very first interaction a visitor made. INP measures responsiveness across every interaction throughout the entire visit — every click, every tap, every keystroke — and reports the worst (or close to worst) one.
Why does that matter? Because a site can respond snappily to that first click and then get sluggish once more scripts load, more content renders, or a visitor starts actually using the page — filling out a form, opening a menu, adding something to a cart. First Input Delay would’ve missed that entirely. INP catches it.
Why this matters for your business, not just your rankings
It’s easy to file this under “SEO technicality,” but the ranking impact is really the secondary concern. The primary one is this: a slow, unresponsive interaction is one of the most direct ways to lose a customer who was already interested.
Think about the moments INP is actually measuring — someone trying to open your booking calendar, filter your product catalog, or submit a contact form. If the page hesitates, stutters, or feels laggy in that exact moment, you’re not just risking a ranking ding. You’re risking the sale, right as someone was reaching for their wallet.
What causes poor INP scores
A few common culprits, especially on small business sites:
- Heavy, unoptimized JavaScript. Plugins, widgets, chat tools, and tracking scripts piling up over time, each adding a little more processing weight to every interaction.
- Too many third-party embeds. Booking widgets, review plugins, social feeds — each one is a small tax on responsiveness, and they add up.
- Poorly optimized e-commerce or filtering features. Product filters, cart updates, and search-as-you-type features are common INP trouble spots because they’re interaction-heavy by nature.
- Outdated themes or bloated page builders that were never built with this kind of performance discipline in mind.
How to check where you stand
You don’t need to become a performance engineer to get a read on this:
- Google’s PageSpeed Insights will show you your site’s real-world INP score (assuming you have enough traffic for Google to have field data) alongside the other Core Web Vitals.
- Google Search Console’s Core Web Vitals report shows you this at the site-wide level, flagging which pages are in “poor,” “needs improvement,” or “good” territory.
- Pay attention to your most interaction-heavy pages specifically — checkout flows, contact forms, filterable product or service pages — since that’s where a poor INP score will cost you the most in actual lost conversions, independent of any ranking effect.
What to do if your score is poor
This is genuinely a “have a professional look at it” situation more than a DIY fix, because the causes are usually buried in code, not settings. But the productive first conversation to have with whoever manages your site is specific: not “is our site fast,” but “what does our INP score look like, and what’s causing it.”
The bottom line
INP isn’t a new hoop to jump through for its own sake — it’s Google getting better at measuring something that was always true: a site that feels sluggish the moment someone tries to actually do something on it is a site that loses customers, quietly, one frustrated click at a time. Worth knowing the term, and worth asking the question.
Curious what your site’s INP score actually looks like? That’s a quick, concrete thing we can check.
