Core Web Vitals 2025: The Complete Guide to Interaction to Next Paint (INP)

Understanding Google’s newest Core Web Vital and how it impacts your website’s performance and search rankings

At SEO Design Chicago, a top rated marketing agency located in Chicago, we understand that staying ahead of Google’s evolving performance standards is crucial for maintaining competitive search rankings. In March 2024, Google introduced Interaction to Next Paint (INP) as the newest Core Web Vital, replacing First Input Delay (FID) to provide a more comprehensive measure of user interaction responsiveness.

This guide provides you with the essential information needed to understand, measure, and optimize for INP to ensure your website delivers the user experience Google rewards with higher search rankings.

What is Interaction to Next Paint (INP)?

Interaction to Next Paint (INP) is a Core Web Vital metric that assesses a page’s overall responsiveness to user interactions throughout the entire duration of a user’s visit. Unlike its predecessor First Input Delay (FID), which only measured the delay of the first interaction, INP observes the latency of all click, tap, and keyboard interactions that occur during a user’s session.

INP measures the time from when a user initiates an interaction (such as clicking a button or tapping a link) to when the browser is able to paint the next frame showing the visual result of that interaction. The metric captures the single longest duration from all interactions on a page, providing insight into your website’s worst-case responsiveness scenario.

How INP Calculation Works

For most websites, INP reports the interaction with the worst latency as the final score. However, Google has implemented a more nuanced approach for pages with high interaction volumes:

• For pages with 50 or fewer interactions: The worst interaction determines the INP score
• For pages with more than 50 interactions: The highest interaction is excluded for every 50 interactions to account for random outliers
• The 75th percentile of all page views is used for the final measurement

This approach ensures that occasional technical hiccups don’t unfairly penalize otherwise responsive websites while still capturing genuine performance issues.

INP Performance Thresholds

Google has established clear performance benchmarks for INP measurement:

Good Performance (Green): INP at or below 200 milliseconds

• Indicates excellent responsiveness that meets user expectations
• Provides a smooth, engaging user experience
• Contributes positively to search engine rankings

Needs Improvement (Yellow): INP between 200-500 milliseconds

• Suggests noticeable delays that may impact user satisfaction
• Requires optimization to meet Google’s performance standards
• May negatively affect search performance over time

Poor Performance (Red): INP above 500 milliseconds

• Indicates significant responsiveness issues
• Creates frustrating user experiences that increase bounce rates
• Likely to impact search rankings and conversion rates

To achieve optimal performance, your website should maintain an INP score below 200 milliseconds for at least 75% of page loads across both mobile and desktop devices.

Key Differences Between INP and First Input Delay (FID)

Understanding the evolution from FID to INP helps clarify why this change represents a significant improvement in user experience measurement:

First Input Delay (FID) Limitations:

• Measured only the input delay of the first interaction on a page
• Focused primarily on the initial loading experience
• Provided limited insight into ongoing user experience
• Did not account for the complete interaction lifecycle

Interaction to Next Paint (INP) Improvements:

• Monitors all interactions throughout the entire page session
• Measures the complete interaction process from initiation to visual feedback
• Provides a comprehensive view of overall page responsiveness
• Better reflects real-world user experience patterns

This transition represents Google’s commitment to capturing more accurate user experience data that reflects how people actually interact with websites beyond the initial page load.

Which Interactions Does INP Monitor?

INP focuses on the most common and impactful user interactions:

Tracked Interactions:

• Mouse clicks on buttons, links, and interactive elements
• Touch screen taps on mobile devices
• Keyboard input in forms, search fields, and text areas
• Complex interactions like dropdown menus, accordion expansions, and modal openings

Excluded Interactions:

• Scrolling behavior (vertical and horizontal)
• Hover effects and mouse-over events
• Pinch-to-zoom gestures
• Drag and drop actions

This focused approach ensures INP measurement concentrates on interactions that directly impact user task completion and satisfaction.

Essential Tools for Measuring INP

Google PageSpeed Insights

PageSpeed Insights provides the most accessible method for checking your current INP performance:

1. Navigate to PageSpeed Insights
2. Enter your website URL
3. Review the Core Web Vitals section for INP scores
4. Analyze both mobile and desktop performance data
5. Examine the diagnostic section for specific optimization opportunities

The tool displays real-world user data from the past 28 days, making it essential to allow sufficient time after implementing optimizations to see results reflected in your scores.

Google Search Console

Search Console’s Core Web Vitals report offers site-wide INP analysis:

• Access comprehensive performance data across all indexed pages
• Identify pages with poor INP performance requiring immediate attention
• Monitor performance trends over time
• Group similar pages to identify systematic issues
• Track improvement progress following optimization efforts

Chrome DevTools Performance Analysis

For detailed technical analysis, Chrome DevTools provides real-time interaction monitoring:

1. Open Chrome DevTools and navigate to the Performance tab
2. Record user interactions during typical browsing sessions
3. Analyze interaction timelines to identify bottlenecks
4. Examine JavaScript execution patterns affecting responsiveness
5. Debug specific elements causing performance issues

Proven Strategies for INP Optimization

1. Optimize JavaScript Execution

Minimize Long Tasks Break down JavaScript operations exceeding 50 milliseconds into smaller, manageable tasks. Long-running scripts block the main thread and prevent timely interaction responses.

Implementation Approach:

• Audit existing JavaScript for extended execution times
• Implement task scheduling using the Scheduler API
• Use setTimeout() or requestIdleCallback() for non-critical operations
• Prioritize user-facing interactions over background processes

Remove Unused Code Eliminate unnecessary JavaScript that contributes to processing overhead without providing user value.

Optimization Steps:

• Conduct code coverage analysis using Chrome DevTools
• Remove deprecated functions and unused libraries
• Implement code splitting to load only required scripts
• Regularly audit third-party integrations for necessity and performance impact

2. Improve DOM Management

Optimize DOM Size Large DOM structures require more processing power for interaction handling and visual updates.

Best Practices:

• Maintain DOM size under 1,400 nodes when possible
• Avoid deeply nested HTML structures
• Use CSS containment properties for off-screen content
• Implement virtual scrolling for large data sets

Minimize Layout Thrashing Reduce unnecessary DOM manipulations that trigger expensive layout recalculations.

Technical Implementation:

• Batch DOM reads and writes to minimize reflow operations
• Use CSS transforms instead of properties that affect layout
• Implement efficient event delegation patterns
• Cache DOM queries to avoid repeated element selection

3. Enhance User Feedback Systems

Provide Immediate Visual Response Users need immediate acknowledgment that their interactions have been registered, even when processing takes time.

User Experience Improvements:

• Display loading indicators for form submissions
• Show progress bars for multi-step processes
• Implement button state changes (pressed, loading, completed)
• Use skeleton screens during content loading

Optimize Perceived Performance Create the impression of faster responsiveness through strategic user interface design.

Implementation Techniques:

• Pre-load critical interaction states
• Use CSS transitions to smooth state changes
• Implement optimistic UI updates where appropriate
• Provide contextual feedback throughout user workflows

4. Third-Party Script Management

Audit External Dependencies Third-party scripts often contribute significantly to interaction delays without providing proportional value.

Evaluation Process:

• Inventory all external scripts and their performance impact
• Assess the business value of each third-party integration
• Implement asynchronous loading for non-critical scripts
• Consider lightweight alternatives for heavy integrations

Optimize Loading Strategies Control how and when third-party scripts execute to minimize interaction interference.

Technical Approaches:

• Use async and defer attributes appropriately
• Implement script loading prioritization
• Load non-essential scripts after user interactions
• Monitor third-party performance regularly

5. Advanced Caching Implementation

Leverage Browser Caching Effective caching strategies reduce server response times and improve interaction responsiveness.

Caching Optimization:

• Implement appropriate Cache-Control headers
• Optimize back/forward cache (bfcache) eligibility
• Use service workers for advanced caching strategies
• Configure CDN settings for optimal performance

Back/Forward Cache Optimization Ensure your pages can benefit from instant back/forward navigation.

Technical Requirements:

• Avoid unload event handlers that prevent bfcache eligibility
• Implement proper cleanup for ongoing connections
• Use pagehide events instead of unload for necessary cleanup
• Test bfcache compatibility using Chrome DevTools

Industry-Specific INP Considerations

E-commerce Optimization

Online retail websites require particular attention to checkout processes, product interactions, and search functionality:

• Optimize shopping cart updates and product variation selections
• Minimize delays in checkout form processing
• Improve search autocomplete and filtering responsiveness
• Enhance product image gallery interactions

Content Publishing

News sites, blogs, and content platforms should focus on reading experience optimization:

• Optimize comment system interactions
• Improve social sharing button responsiveness
• Enhance navigation menu performance
• Streamline subscription and newsletter signup processes

Service-Based Businesses

Professional service websites require optimal contact form and scheduling system performance:

• Minimize contact form submission delays
• Optimize appointment booking system interactions
• Improve quote request form responsiveness
• Enhance consultation scheduling interfaces

Common INP Optimization Pitfalls

Over-Engineering Solutions

Implementing complex optimization strategies that actually worsen performance through increased overhead.

Prevention Strategies:

• Test performance impact of each optimization
• Implement changes incrementally with measurement
• Prioritize simple, effective solutions over complex implementations
• Monitor for unintended performance regressions

Neglecting Mobile Performance

Focusing exclusively on desktop optimization while ignoring mobile interaction patterns.

Mobile-First Approach:

• Test on actual mobile devices, not just emulators
• Consider touch interaction patterns and timing
• Account for varying network conditions and device capabilities
• Optimize for thumb-friendly interaction zones

Ignoring Real-World Usage Patterns

Optimizing for synthetic tests without considering actual user behavior.

User-Centric Testing:

• Implement Real User Monitoring (RUM) for actual performance data
• Analyze heat maps and user session recordings
• Test with realistic user scenarios and interaction patterns
• Consider accessibility requirements for diverse user needs

Measuring Success and Ongoing Optimization

Establishing Baseline Metrics

Before implementing optimizations, document current performance across key pages and user flows.

Documentation Process:

• Record INP scores for primary landing pages
• Document performance for critical user interactions
• Note device and connection type variations
• Establish improvement targets based on business goals

Continuous Monitoring

INP optimization requires ongoing attention as website content and functionality evolve.

Monitoring Strategy:

• Implement automated performance monitoring
• Set up alerts for performance threshold violations
• Schedule regular performance audits
• Track correlation between INP improvements and business metrics

Performance Budget Management

Establish performance budgets that prevent future regressions while allowing for necessary feature additions.

Budget Implementation:

• Define maximum acceptable INP thresholds for different page types
• Include performance testing in development workflows
• Implement performance gates in deployment processes
• Regular team training on performance-conscious development practices

Future-Proofing Your INP Strategy

Google continues to refine Core Web Vitals based on real-world usage patterns and technological advances. Staying ahead requires understanding emerging trends and preparing for future changes.

Emerging Technologies

• Progressive Web App (PWA) optimization techniques
• Edge computing for reduced latency
• Advanced preloading and prefetching strategies
• AI-powered performance optimization tools

Development Best Practices

• Performance-first development methodologies
• Automated performance testing integration
• Cross-functional collaboration between design and development teams
• User experience research integration with technical optimization

Implementation Roadmap

Phase 1: Assessment and Planning (Week 1-2)

• Conduct comprehensive INP audit across key pages
• Identify highest-impact optimization opportunities
• Establish performance baselines and improvement targets
• Develop implementation timeline and resource allocation

Phase 2: Quick Wins Implementation (Week 3-4)

• Remove unused JavaScript and CSS
• Implement basic user feedback mechanisms
• Optimize third-party script loading
• Address obvious performance bottlenecks

Phase 3: Advanced Optimization (Week 5-8)

• Implement JavaScript task scheduling and optimization
• Optimize DOM structure and manipulation patterns
• Enhance caching strategies and browser optimization
• Conduct thorough testing across devices and conditions

Phase 4: Monitoring and Refinement (Ongoing)

• Establish continuous performance monitoring
• Regular performance audits and optimization cycles
• Team training and best practice documentation
• Integration with business metrics and goal tracking

Conclusion

Interaction to Next Paint represents a significant evolution in how Google measures and rewards user experience quality. By understanding INP’s comprehensive approach to interaction responsiveness and implementing the optimization strategies outlined in this guide, you can ensure your website delivers the performance that both users and search engines expect.

Success with INP requires a holistic approach that combines technical optimization with user experience design and ongoing performance monitoring. The websites that prioritize INP optimization now will maintain competitive advantages as Google continues to emphasize user experience quality in search rankings.

For businesses seeking professional assistance with INP optimization and comprehensive Core Web Vitals improvement, SEO Design Chicago, a top rated marketing agency located in Chicago, provides customized solutions that deliver measurable results. Contact us to discuss how we can help optimize your website’s performance and search engine visibility.