How is Interaction to Next Paint measured on a website?

Interaction to Next Paint is measured by tracking the latency of all qualified user clicks, taps, and keypresses during a page visit. The browser calculates the combined input delay, script execution time, and rendering delay for each interaction. It then reports a single value representing the worst overall response time.

Why did Interaction to Next Paint replace First Input Delay?

Interaction to Next Paint replaced First Input Delay because it provides a more complete picture of page performance. While First Input Delay only measured the initial delay before processing the very first click, the updated metric evaluates the full visual response time across all interactions throughout the session.

SEO

Interaction to Next Paint

Interaction to Next Paint is a metric that measures how long a webpage takes to update visually after a user taps, clicks, or presses a key on their keyboard.

also called: INP

// definition

Much like timing how quickly a light switch turns on a lamp, this performance metric records the delay between a user action and the updated display. It measures interface responsiveness for click, tap, and keyboard inputs across a visitor's entire session on a page.

The score records the worst or near-worst overall response time. It combines input delay before processing, event handler execution time, and presentation delay required to render the new visual frame. Unlike First Input Delay, which tracked only the initial delay, it tracks all interactions until the user leaves.

// Interaction to Next Paint vs. Time to First Byte

Time to First Byte tracks how quickly a web server sends initial data after a request, while Interaction to Next Paint measures how fast the interface visually responds to user actions. For an independent bookshop's events calendar, Time to First Byte measures how fast the calendar page begins loading.

In contrast, Interaction to Next Paint measures the delay when a visitor clicks a date to view ticket details. Interaction to Next Paint evaluates client-side responsiveness across multiple clicks throughout a visit, whereas Time to First Byte measures only server response speed before page rendering starts.

// why it matters

Slow visual responses cause frustration when visitors fill out forms, open menus, or add items to a shopping cart. When a webpage delays updating its display, users often click elements multiple times. This leads to unintended duplicate actions or immediate site abandonment.

Search engines also evaluate user interface responsiveness as part of page ranking signals. Improving visual response times ensures that digital actions feel immediate. This helps businesses retain site visitors, boost user satisfaction, and prevent drop-offs during important online transactions.

Questions and Answers

How is Interaction to Next Paint measured on a website?: Interaction to Next Paint is measured by tracking the latency of all qualified user clicks, taps, and keypresses during a page visit. The browser calculates the combined input delay, script execution time, and rendering delay for each interaction. It then reports a single value representing the worst overall response time.
Why did Interaction to Next Paint replace First Input Delay?: Interaction to Next Paint replaced First Input Delay because it provides a more complete picture of page performance. While First Input Delay only measured the initial delay before processing the very first click, the updated metric evaluates the full visual response time across all interactions throughout the session.