Interaction to Next Paint (INP) measures how quickly your page responds to user interactions. It replaced FID as a Core Web Vital in March 2024 and is now a Google ranking factor.

Thresholds

Google recommends 200 milliseconds or less for at least 75% of page visits.

INP vs FID

FID only measured the first interaction's input delay. INP measures all interactions throughout the page lifecycle, including processing time and rendering. Since 90% of user time is spent after page load, INP better reflects actual experience.

Why It Matters

While 93% of sites had good FID, only 74% have good INP. Users expect instant feedback - slow interactions make sites feel broken.

Common Issues

• Long-running JavaScript blocking main thread
• Heavy event handlers
• Third-party scripts (analytics, ads)
• Hydration delays in SPAs

Measure INP

• PageSpeed Insights (field data)
• Search Console Core Web Vitals report
• Web Vitals Chrome extension
• TBT as lab proxy

→ Complete INP Guide