Measures page responsiveness using interaction latency throughout a visit. A good result is 200 milliseconds or less.
Interaction to Next Paint describes how promptly a page responds visually to user interactions during a visit. It observes clicks, taps and keyboard interactions, not just the first action after loading. The measurement includes the wait before event processing, the processing itself and the delay before the browser can paint the next response.
A good INP is 200 milliseconds or less at the 75th percentile of measured visits for the relevant device group. It is not a measurement of how long an entire business transaction takes. A page can acknowledge a form submission promptly while a server continues processing the request; the immediate visual response and the completed transaction are different events.
When a page feels unresponsive, investigate the interaction that caused the delay. A menu, filter or custom form can behave differently from the rest of the site. A quick initial page load does not prove that later interactions will be responsive, especially if additional scripts or large updates run after the visitor starts using the page.
Takeaway: Test the controls customers actually use, not just the landing screen. Prioritize delayed interactions on important journeys and provide clear feedback without claiming an unfinished transaction has s\ucceeded.
Example
A florist’s bouquet page appears quickly, but selecting a delivery date freezes the interface while a large availability calculation runs. The team reproduces that date-picker interaction and investigates its work rather than replacing the page’s already-fast hero image.
What to check
Ask a developer to measure a representative interaction sequence on a realistic device. Include later steps such as changing a selection or correcting a form error. A page-load-only test may never exercise the action customers find slow.
For more detail, see Web.dev INP guide.