What is Interaction to Next Paint (INP)?
Interaction to Next Paint (INP) is a Web Vital metric that quantifies how long a webpage takes to respond visually to user interactions. It measures the time between when a user interacts with a page (clicking a button, typing in a form, tapping a link) and when the browser displays the next visual update.
INP replaced First Input Delay (FID) as Google's official responsiveness metric in March 2024. Unlike FID, which only measured the first interaction, INP evaluates all interactions throughout a page's lifecycle and reports the worst one, providing a more comprehensive picture of overall responsiveness.
Why INP Matters for UK Marketers
Responsiveness directly impacts user experience and conversion rates. If a user clicks a "Buy Now" button and nothing happens for two seconds, they're likely to abandon the purchase. For UK e-commerce sites, media platforms, and lead-generation pages, poor INP scores mean lost revenue.
Google uses INP as a ranking factor in its Core Web Vitals assessment. Pages with poor INP scores may rank lower in search results, affecting organic visibility. This matters particularly for competitive UK markets where ranking position directly correlates with traffic and revenue.
How INP Works
The metric captures three components:
- Input delay: Time from interaction to the browser beginning to process it
- Processing time: Duration the browser takes to execute event handlers
- Presentation delay: Time to display visual feedback
A "good" INP score is 200 milliseconds or less. Scores between 200-500ms need improvement, whilst anything over 500ms is poor.
When INP is Used
INP applies to all interactive websites: e-commerce platforms, SaaS applications, content sites with comment sections, and any page requiring user input. It's particularly critical for:
- E-commerce checkouts where form responsiveness affects abandonment
- Media and publishing where ad interactions must feel instant
- Lead generation where form submission feedback matters
- Mobile experiences where interaction delays are more noticeable
Improving INP
Common optimisations include breaking up long JavaScript tasks, optimising event handlers, deferring non-critical code, and improving server response times. Tools like Google PageSpeed Insights and Chrome's DevTools help identify problematic interactions.
For UK agencies managing multiple client accounts, monitoring INP across campaigns helps ensure that marketing investments drive genuine user engagement rather than frustration.