What is INP in Core Web Vitals | What is Interaction To Next Paint | How to Optimize INP

Website performance is a crucial factor in search rankings, user experience, and overall digital success. Google has long used Core Web Vitals to measure a page’s performance, focusing on three key metrics:

1. Largest Contentful Paint (LCP) – Measures loading performance.
2. First Input Delay (FID) – Measures interactivity.
3. Cumulative Layout Shift (CLS) – Measures visual stability.

However, a major update is coming in March 2024. Google is introducing Interaction to Next Paint (INP), which will replace FID. But what is INP, and why does it matter?

What is INP?

INP stands for Interaction to Next Paint. It measures the time between when a user interacts with a page (click, tap, or keypress) and when the browser responds visually to that interaction.

We’ve all encountered situations where we click a button, but nothing happens immediately. We click again, and suddenly, everything responds at once—sometimes in an unexpected way. This delay creates a poor user experience, and INP helps quantify this issue.

How is INP Measured?

• If your INP is under 200 milliseconds, your site is performing well.
• If INP is between 200–400 milliseconds, you receive a warning.
• If INP exceeds 400 milliseconds, your site fails this Core Web Vitals metric.

How Does INP Affect Your Website?

Google calculates the INP score by looking at the slowest interactive element on your page. If one button loads in 100ms, another in 200ms, a tab in 300ms, but a menu icon takes 600ms, then your page’s INP is 600ms—not the average, but the worst-performing element.

For highly interactive pages, Google may consider the second or third longest interaction instead of just the worst, but the goal remains the same: reduce delays in all interactive elements.

How to Improve INP on Your Website

Optimizing INP requires fine-tuning multiple aspects of web development. Here are some strategies:

1. Optimize JavaScript and CSS Execution

• Reduce heavy JavaScript execution that blocks the browser’s response.
• Defer unnecessary scripts and prioritize essential interactions.

2. Remove Unused CSS and JavaScript

• Even if unused, the browser downloads and processes all code, slowing interactions.
• Use tools to remove unnecessary styles and scripts to speed up processing.

3. Minimize JavaScript and CSS Files

• Compress and minify files to reduce load times and improve INP.
• Every millisecond counts—saving even 1 second in execution can drastically improve performance.

4. Use Caching Plugins

• Cache frequently used scripts and assets to reduce execution load.
• This frees up browser processing power, improving interactivity.

Why This Matters for SEO & User Experience

With Google making INP a Core Web Vital metric in 2024, failing to optimize could impact search rankings. A slow, unresponsive site leads to higher bounce rates and lost conversions.

By implementing the above strategies, businesses can ensure smooth, fast interactions—keeping users engaged and search rankings intact.

Are you ready for Google’s INP update? Start optimizing today!