Answers · Websites & Page Speed
What is Interaction to Next Paint (INP)?
Last reviewed: · Strategic AI Architects Data Desk · reviewed by Mike Moore
Interaction to Next Paint measures how long a page takes to visually respond when a visitor clicks, taps, or presses a key — reported as approximately the slowest such interaction across the whole visit — and Google's published threshold for good is 200 milliseconds or less, assessed at the 75th percentile of real page loads (web.dev, "Interaction to Next Paint (INP)," verified live August 18, 2026).
The qualifier: "respond" means the next paint — the screen visibly changing — not the operation finishing. If a visitor taps "Get my quote" and the form takes 900 ms to submit but the button shows a pressed state within 100 ms, INP records the 100 ms. That is deliberate: the metric targets the specific failure where a page appears to ignore the visitor, which is what makes people tap twice and assume the site is broken. INP became a Core Web Vital on March 12, 2024, replacing First Input Delay (web.dev announcement, "Interaction to Next Paint is officially a Core Web Vital," March 12, 2024).
The INP bands Google publishes
| Band | INP | What a visitor experiences |
|---|---|---|
| Good | 200 ms or less | Taps feel immediate |
| Needs improvement | 200 to 500 ms | A perceptible lag on interactions |
| Poor | Over 500 ms | The page seems to ignore input; visitors tap again |
For an insurance agency site, INP is mostly a budget question: every third-party script — tag manager, chat widget, session recorder, accessibility overlay — competes for the same main thread that has to answer the visitor's tap. Our production builds pass INP the unglamorous way, by shipping near-zero JavaScript on static pages so the main thread is idle when the tap arrives; it is one reason those builds measure 99-100 on mobile PageSpeed (SAA build measurements, July-August 2026). And because INP needs real interactions, it is assessed from field data — one more way the lab score and the field verdict can diverge.
Sources
- web.dev (Google). "Interaction to Next Paint (INP)" — definition, the 200 ms / 500 ms thresholds at the 75th percentile, and next-paint semantics. Verified live 2026-08-18. web.dev.
- web.dev (Google). "Interaction to Next Paint is officially a Core Web Vital," 2024-03-12 — INP replacing First Input Delay. web.dev.
- web.dev (Google). "Optimize Interaction to Next Paint" — long tasks and main-thread work as the primary causes. Verified live 2026-08-18. web.dev.
- Strategic AI Architects. Production build measurements via PageSpeed Insights, July-August 2026.
Related questions
Why did INP replace First Input Delay?
Because FID measured too little: only the input delay — the wait before the browser could even start handling the event — and only for the first interaction of the visit. INP measures the full time from interaction to the next screen update, for interactions across the whole visit, so a page that responds instantly once and then chokes on every later tap can no longer pass. The switch was announced on web.dev and took effect March 12, 2024.
What makes INP slow in practice?
JavaScript keeping the main thread busy. Long tasks from heavy scripts — analytics, chat widgets, page builders, tag managers — mean the browser cannot process the visitor's tap until the current task finishes. web.dev's INP guidance centers on breaking up long tasks and reducing main-thread work, which in practice usually means shipping less third-party JavaScript.
Does INP show up in a Lighthouse lab test?
Not directly — INP requires real interactions, so it is primarily a field metric from the Chrome UX Report. Lighthouse reports Total Blocking Time as its lab proxy for responsiveness, which is why a page's lab score can look fine while field INP fails, and another reason the lab and field numbers on one URL can disagree.
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