INP is a Core Web Vitals metric that measures how quickly a page responds to user interactions: clicks, taps, and keyboard input. INP captures the delay between the interaction and the next visual update of the interface. In March 2024, Google officially replaced the previous FID metric with INP, and since fall 2024, INP has been used to assess page quality across all Google tools.

For website owners and SEO specialists in Moscow and the region, understanding INP is critical: it's not just a technical characteristic but a factor influencing search rankings and behavioral metrics. If the interface regularly freezes when users click buttons, open filters, or add items to the cart, they leave for competitors, and search engines register worsening behavioral signals. Learn more about modern promotion methods in the article on new search trends.

What INP Measures and How It's Calculated

INP analyzes all user interactions with the page during a session and records the slowest one. This is a fundamental difference from its predecessor FID, which only considered the first interaction.

The metric evaluates the full response cycle of the interface, which consists of three stages:

• Input delay: the time between the user's action and the browser starting to process the event.
• Processing time: the period during which JavaScript code runs in event handlers.
• Presentation delay: the time the browser needs to render the next frame after processing completes.

The final INP value is the worst delay among all user interactions, measured at the 75th percentile of all sessions. For highly interactive pages, the system ignores the single longest interaction per 50 to exclude random outliers and assess real responsiveness.

INP Thresholds in 2026

Google has set clear thresholds for INP that are important to consider during optimization:

• Up to 200 milliseconds — excellent, the page is considered responsive.
• From 200 to 500 milliseconds — optimization needed; users may feel delays.
• Over 500 milliseconds — poor responsiveness, high risk of traffic loss and conversion drops.

In 2025, Google tightened the thresholds, and now to hit the "green zone," it's recommended to aim for 150 milliseconds on mobile devices. This is especially relevant for Moscow audiences with high expectations for interface speed.

Why INP Matters for Search Engine Rankings

INP is officially part of Core Web Vitals and serves as a signal for Google's search algorithm when assessing page quality. While a poor INP alone rarely causes a sharp drop in rankings, it affects the overall user experience picture that search engines consider during ranking.

According to 2025 research, sites that consistently fail Core Web Vitals lose to competitors with fast, responsive pages in organic traffic volume. Slow response to user actions worsens behavioral factors: bounce rates rise, and depth of view and time on site decline.

In the context of AI-driven search, INP gains additional significance: poorly responding sites receive worse behavioral signals, reducing trust in the source and decreasing the likelihood of content being used in AI answers. A comprehensive SEO audit helps identify interface responsiveness issues early.

Main Causes of Poor INP

Most often, INP issues arise from unoptimized JavaScript. While the browser's main thread is busy executing heavy scripts, it can't respond quickly to user actions.

Here's what typically worsens INP:

• Heavy and blocking JavaScript: large volumes of unoptimized code that loads and executes unnecessarily.
• Long tasks: code fragments running longer than 50 milliseconds that block the main thread.
• Third-party scripts: numerous widgets, analytics counters, and ad modules that load the network and slow down the interface.
• Frequent DOM manipulations: constant changes to the page structure and style recalculations during interactions.
• Complex page structure: an overly large DOM tree slows down interface repainting.

INP issues are especially common with online chat and callback widgets, which are widely used on Moscow companies' websites. Professional page speed optimization includes analyzing and optimizing these elements.

How to Check Your Site's INP

For INP diagnostics, use several tools to get an objective picture:

• Google Search Console: the Core Web Vitals report shows which pages have INP issues based on real user data.
• PageSpeed Insights: analyzes a specific page and provides recommendations for improvement, including INP data.
• Chrome DevTools (Performance tab): lets you record interactions with the site and see the duration of each INP phase in lab conditions.
• Yandex.Metrica: the "Load Speed" report helps assess how quickly the site responds to real users from Moscow and the region.

Remember: INP relies on field data, so for low-traffic sites, the metric may not appear. In such cases, use TBT as a proxy metric and employ real-user monitoring systems.

How to Improve INP: Practical Recommendations

Optimizing INP requires systematic work on interface performance. The main goal is to free up the browser's main thread so it can respond quickly to user actions.

JavaScript Optimization

Reduce unused code through code splitting and lazy loading. Use async and defer attributes for non-critical scripts. Minimize the use of heavy libraries—sometimes a few lines of vanilla JavaScript work faster than loading a framework.

Breaking Up Long Tasks

Code fragments running longer than 50 milliseconds block the main thread. Break them into smaller pieces using setTimeout so the browser can process user input between tasks.

Optimizing Third-Party Scripts

Analyze which external services are truly necessary on the page. Load third-party scripts with deferred priority so they don't interfere with key user scenarios. Effective SEO promotion in Yandex requires a balance between functionality and performance.

Reducing DOM Load

Simplify the page structure: reduce the number of elements and nesting depth. Avoid frequent DOM manipulations in loops—group changes and apply them at once. Use simpler CSS selectors to speed up style recalculations.

Controlling Forced Reflows

Don't mix reading and writing styles in the same loop—this causes forced reflows. For example, don't request offsetHeight immediately after changing an element's class.

Conclusion

INP is a metric that evaluates a site's real responsiveness to user actions throughout the entire visit. In 2026, it has become an integral part of Core Web Vitals and an important signal for Google's search ranking. For businesses in Moscow and the region, where competition is high and audiences are demanding, a poor INP means direct losses: users won't wait for the interface to respond and will switch to faster competitors. Systematic JavaScript optimization, breaking up long tasks, and simplifying the DOM structure will help keep INP in the green zone and maintain search positions. To learn which methods no longer work, read the article on what no longer works in SEO.

FAQ on the INP Metric

How is INP different from FID?
FID measured only the delay of the first interaction and only the input phase. INP considers all user interactions during a session and measures the full cycle: from click to rendering the next frame.

Does INP affect Yandex rankings?
Yandex doesn't directly use INP, but it evaluates behavioral factors and interface response speed through its Site Quality Index. Responsiveness metrics influence how users perceive the site, which indirectly affects rankings.

Why is there sometimes no INP data in reports?
INP requires real user interactions. If visitors only view the page without clicks or input, the metric isn't generated. Data may also be missing for low-traffic sites.

Where to start if INP is in the red zone?
Start with an audit of third-party scripts and check for long tasks in Chrome DevTools. Often, disabling or deferring unnecessary widgets and breaking up heavy JavaScript operations is enough to improve the metric.