INP (Interaction to Next Paint) measures how fast a website responds to user actions like clicks, taps, or typing. Unlike older metrics like FID (First Input Delay), which only tracked the first interaction, INP evaluates responsiveness across all interactions during a user’s session. This makes it a key indicator of user experience and an important factor for SEO rankings.
Here’s what you need to know:
- Replaced FID in Google’s Core Web Vitals on March 12, 2024.
- Tracks the time between a user’s action and visible feedback on the screen.
- Focuses on responsiveness throughout the session, not just the initial load.
- A good INP score is 200ms or less, with anything over 500ms considered poor.
- Directly impacts SEO, as slow responsiveness can lead to lower rankings and higher bounce rates.
How INP Works:
- Measures the delay in three stages: input delay, processing time, and presentation delay.
- Calculates the 75th percentile of the longest delays across interactions to give a realistic measure of performance.
- Tools like Chrome DevTools and Lighthouse can help diagnose and improve INP scores.
Improving INP involves optimizing JavaScript, event handlers, and reducing main-thread blocking tasks. Sites with better INP scores see higher engagement, lower bounce rates, and improved SEO performance.
How INP Works and What It Measures
How INP Measurement Works
INP measures how quickly a webpage responds to user interactions by tracking clicks, taps, and key presses through the Event Timing API. Here’s how it works: when you interact with an element – like tapping a button or clicking a link – the browser starts a timer. This timer runs until the next visual update appears on your screen, capturing the time it takes for the interaction to be processed.
Each interaction’s latency is broken down into three key stages:
- Input Delay: The time it takes for the browser to begin processing your interaction.
- Processing Time: The duration required for JavaScript execution and related calculations.
- Presentation Delay: The time needed for the browser to update the screen with the visual change.
For interactions involving multiple events, the browser uses the event with the longest duration to determine latency. During a session, the browser monitors all user interactions and identifies the one with the longest delay. To minimize the impact of outliers, the system ignores the single longest interaction for every 50 interactions when a page has high activity levels.
The final INP score is calculated as the 75th percentile of the longest delays observed across all interactions on a page. This calculation is done separately for mobile and desktop devices. By focusing on the 75th percentile, the metric reflects the experience of most users, avoiding skewed results caused by rare but extreme delays. This method ensures a reliable measure of responsiveness and sets the stage for defining acceptable thresholds.
INP Score Thresholds
Google suggests that a responsive and high-quality user experience is represented by an INP score of 200 milliseconds or less. These thresholds are essential for evaluating INP alongside other Core Web Vitals metrics.
INP vs. Other Core Web Vitals
INP stands out in the Core Web Vitals framework by specifically focusing on responsiveness – how quickly a webpage reacts to user inputs and updates the screen. By comparison:
- Largest Contentful Paint (LCP): Measures how quickly the main content of a page loads.
- Cumulative Layout Shift (CLS): Tracks visual stability by measuring unexpected layout shifts during loading.
Together, these metrics provide a well-rounded view of user experience. While LCP and CLS primarily address the initial loading phase, INP covers the entire session, making it especially important for interactive and dynamic websites. Poor performance in any of these areas can lead to reduced user satisfaction and engagement. This highlights why improving INP is critical for ensuring seamless real-time interactions.
Why INP Matters for Website Performance and SEO
Impact on User Experience
When your site’s INP (Interaction to Next Paint) scores are poor, users experience delays in actions like clicking buttons, submitting forms, or navigating between pages. These slow responses make your site feel unresponsive and sluggish. On mobile devices, where people expect quick, app-like interactions, such delays are especially frustrating. They can lead users to abandon tasks like completing a checkout or filling out forms. This lack of responsiveness doesn’t just irritate visitors – it also contributes to higher bounce rates, lower engagement, and ultimately hurts how users perceive your site.
INP and SEO Rankings
INP isn’t just about how users feel – it’s also a key factor in your site’s search performance. Google has made INP a priority by replacing FID (First Input Delay) with INP in its Core Web Vitals metrics. Essentially, INP can act as a tiebreaker for pages with similar content. If your site has better interaction performance, it can gain an edge in organic search rankings.
For websites that rely heavily on interactive elements, like local businesses or e-commerce platforms, improving INP can lead to noticeable boosts in both SEO rankings and user engagement. By optimizing INP, you’re not just enhancing the user experience – you’re also increasing your site’s potential to rank higher.
Comparison Table: INP vs. Other Core Web Vitals
Here’s a breakdown of how INP stacks up against other Core Web Vitals metrics:
| Metric | What It Measures | Good Threshold | Poor Threshold | Primary Impact | SEO Weight |
|---|---|---|---|---|---|
| INP | Interaction responsiveness throughout the session | ≤ 200ms | > 500ms | User engagement and conversion rates | High |
| LCP | Loading speed of main content | ≤ 2.5s | > 4.0s | First impressions and bounce rates | High |
| CLS | Visual stability during loading | ≤ 0.1 | > 0.25 | User trust and reading experience | Medium |
| FID | First interaction delay | ≤ 100ms | > 300ms | Initial user engagement | None |
This table shows that while metrics like LCP (Largest Contentful Paint) and CLS (Cumulative Layout Shift) focus on how the page loads initially, INP measures how responsive the site is throughout the user’s entire session. This makes it a critical factor for improving conversion rates and maintaining strong search rankings.
Common Causes of Poor INP Scores
Common Technical Issues
Understanding how INP is measured helps identify several technical problems that can hurt its score.
Heavy JavaScript can block the main thread, delaying user responses. When your site runs complex JavaScript during interactions, it prevents the browser from reacting quickly. This is a common issue on sites using large frameworks, multiple third-party scripts, or inefficient code that processes data synchronously.
Unoptimized event handlers can slow down visual updates by performing excessive calculations or making multiple API calls. These handlers are triggered when users click, scroll, or interact with forms. Without proper optimization, they can stretch delays into hundreds of milliseconds.
Main-thread blocking tasks occur when the browser becomes overwhelmed with work. The main thread handles everything from running JavaScript to rendering visuals. Tasks like parsing large JSON files, running animations, or extensive DOM manipulation can pile up, causing noticeable delays.
Third-party widgets and plugins, such as chat tools or social media embeds, compete for main-thread resources. Scripts for analytics and advertising often take up processing time, leaving less room for your site’s core functionality.
Large DOM manipulations slow responsiveness by overloading the browser when adding, removing, or altering elements. This is especially common in single-page applications or e-commerce sites with dynamic content and complex filtering systems.
Together, these technical issues can significantly slow interactions, leading to frustration for users.
Signs of Poor INP Performance
Beyond the technical side, there are clear signs that indicate INP performance problems.
Delayed visual feedback is a major red flag. If users click a button and nothing happens for several hundred milliseconds, or form submissions seem to freeze momentarily, you’re likely dealing with INP issues. These delays often lead users to click multiple times, unsure if their interaction was registered.
Browser performance tools can highlight the problem. In Chrome DevTools, the Performance panel shows tasks exceeding 50 milliseconds. Google’s Lighthouse tool flags INP scores above 200 milliseconds as needing improvement, while scores over 500 milliseconds are rated as "poor."
Mobile devices often amplify INP symptoms. With less processing power than desktops, mobile devices make sluggish interactions – like expanding menus or submitting forms – more apparent. If users experience these delays on mobile, it’s likely a widespread issue.
High bounce rates on interactive pages can also signal INP problems. If analytics show users abandoning shopping carts, leaving forms incomplete, or quickly exiting interactive pages, poor responsiveness could be driving them away.
Console errors and warnings in developer tools often accompany INP issues. Look for messages about long-running scripts, blocked main-thread activities, or performance violations. These technical clues can help you identify the specific code or third-party services causing delays.
What is INP in Google’s Core Web Vitals?
How to Optimize for INP
Improving INP (Interaction to Next Paint) starts with focusing on the most important user interactions. Slow responses can frustrate users and negatively impact conversions.
Prioritizing Critical Interactions
Here’s how you can zero in on the interactions that matter most:
- Use performance monitoring tools like New Relic Browser to spot sluggish interactions. Look for patterns in clicks, form inputs, and navigation events to identify those with consistent delays.
- Optimize event handlers for these key interactions by:
- Debouncing frequent events: For example, limit how often scroll or resize events trigger to avoid overloading the system.
- Using event delegation: When managing multiple interactive elements, this approach minimizes the number of event listeners you need, improving efficiency.
- Caching and pre-calculating: Store DOM queries or compute values outside the event handlers to reduce repetitive processing.
- Avoiding blocking operations: Synchronous tasks, like API calls or file operations, can freeze the main thread. Keep these tasks asynchronous to maintain responsiveness.
- Add immediate visual feedback to keep users engaged. For instance, use loading spinners, change button states, or show progress indicators to signal that their input is being processed.
Conclusion
Since Google replaced FID with INP in March 2024, INP now evaluates the entire interactive experience by measuring responsiveness throughout a visitor’s session. This change highlights what users value most – a site that remains responsive beyond just the initial load.
The stakes for web performance have never been higher. INP directly impacts user engagement and search rankings. Slow responses frustrate users, leading to higher bounce rates, while poor scores over 500 ms can seriously hurt performance.
The business implications of INP optimization are clear. Take, for example, an e-commerce site that improved its INP from 600 ms to 180 ms by refining JavaScript and deferring non-critical scripts. This effort led to a 15% drop in bounce rates and a 10% boost in conversions. These kinds of improvements often align with better search rankings, which enhance both visibility and revenue. Such results highlight the tangible benefits of focusing on INP.
Key Takeaways
- INP is a game-changer for web performance. Unlike FID, which only measured the delay of a user’s first interaction, INP tracks responsiveness across all interactions, offering a more complete picture of site performance.
- Optimization is an ongoing process. Achieving a good INP score – ideally under 200 milliseconds – requires regular monitoring to identify and address performance issues, especially after updates or new features are introduced.
- The benefits extend across the board. Better INP scores improve user engagement, reduce bounce rates, and strengthen SEO performance. As Google continues to emphasize user experience, a responsive site gains a clear edge in search visibility and user retention.
To maintain excellent INP scores, focus on reducing JavaScript blocking, prioritizing critical interactions, and leveraging performance monitoring tools to identify problem areas. For a deeper dive into improving your site’s responsiveness, consider partnering with SearchX for a technical SEO audit. With consistent effort, delivering the fast, responsive experience users expect becomes second nature.
FAQs
How is INP different from other Core Web Vitals like LCP and CLS, and why does it provide a more complete view of website performance?
INP (Interaction to Next Paint) differs from other Core Web Vitals like LCP (Largest Contentful Paint) and CLS (Cumulative Layout Shift) by focusing on how quickly a website reacts to user actions, such as clicks or taps. While LCP measures the time it takes for the main content to load and CLS monitors visual stability during loading, INP zeroes in on the responsiveness of a webpage throughout the entire user session.
What sets INP apart is its ability to capture delays not only during the initial page load but also during ongoing interactions. This broader perspective highlights performance issues that might otherwise go unnoticed, giving a clearer picture of how a site performs in real-world use. By addressing these issues, websites can improve both user satisfaction and overall effectiveness.
How can I improve my website’s INP score to boost responsiveness?
Improving your website’s Interaction to Next Paint (INP) score is all about making your site respond faster and more smoothly to user actions. To start, focus on trimming down any long tasks on the main thread, keeping the DOM size manageable, and postponing non-critical scripts or rendering updates. These steps help your site handle user inputs more efficiently.
Another way to boost responsiveness is by tackling input delays. Use web workers to handle heavy tasks in the background, and avoid making unnecessary visual updates after users interact with your site. Keep an eye on your site’s performance with tools that measure INP metrics, and use that data to make smart, ongoing improvements for a better user experience.
What is INP, and why is it important for SEO and websites with high user interaction?
Interaction to Next Paint (INP) is one of the Core Web Vitals metrics, focusing on how quickly your website reacts to user actions like clicks, taps, or key presses. Essentially, it measures your site’s responsiveness, which is a key factor in delivering a smooth user experience.
For websites with a lot of user interaction, keeping INP performance in check is crucial. Slow response times can irritate visitors, causing them to leave your site quicker and spend less time exploring. And since Google emphasizes user experience in its search rankings, poor INP scores can hurt your SEO efforts. By fine-tuning your INP, you not only improve user engagement but also encourage longer visits and strengthen your site’s overall search visibility.
