The Core Web Vital for responsiveness — measuring the delay from a user interaction (tap, click, key) to the next visual update, reported near the worst across a visit; good is 200ms or less at the 75th percentile.

How do you improve INP?

Break up long JavaScript tasks, reduce synchronous work in event handlers, trim and defer third-party scripts, and minimize the DOM and layout work each interaction triggers — main-thread discipline is the core fix.

Growth Marketing Glossary

Interaction to Next Paint (INP)

in·ter·ac·tion to next paintnoun

From tap to visible response, measured across the whole visit - the responsiveness metric Google made a Core Web Vital.

Schematic — interaction to the next paint

Term: Interaction to Next Paint
Measures: Tap/click → next visual response
Good: ≤200ms at the 75th percentile
Replaced FID: March 12, 2024 (Core Web Vital)

Forms & parts of speech

INP · noun

The responsiveness vital.

"INP caught what FID missed - the page felt fine on the first tap and froze on every one after."

Definition in plain terms

Interaction to Next Paint (INP) is the CORE-WEB-VITALS metric for responsiveness: it measures the time from a user interaction — a tap, click, or key press — to the next visual update the browser paints in response, and reports (roughly) the worst such delay across the whole visit. It replaced First Input Delay (FID) as a Core Web Vital on March 12, 2024, because FID measured only the FIRST interaction's input delay, while INP measures all interactions and the full response, catching the sluggishness real users actually feel.

The mechanics

Why the swap mattered: FID was easy to pass and easy to mislead — it timed only the delay before processing began, only on the first interaction, so a page could score a perfect FID and still feel broken on every subsequent tap (the menu that lags, the filter that freezes, the form that stalls). INP fixes both blind spots: it covers all interactions across the visit (reporting near the worst), and it measures the FULL interaction lifecycle — input delay (waiting for the main thread), processing time (your event handlers running), and presentation delay (rendering the visual response) — so it indicts heavy JavaScript wherever it lives. The thresholds (field data, 75th percentile of real users): good is 200 milliseconds or less, 'needs improvement' to 500ms, poor above 500ms — and because it's a 75th-percentile field metric, it reflects real devices and real conditions, not a fast laptop in a lab. What actually moves it (the optimization work): breaking up long JavaScript tasks (the main-thread monopolizers that block response), reducing the work event handlers do synchronously (defer the non-urgent, yield to the main thread), trimming third-party scripts (the tag-manager and chat-widget weight the PAGE-EXPERIENCE budget pays for), and minimizing the DOM and layout work a single interaction triggers. The honest marketing framing this glossary keeps: Core Web Vitals are a real but modest ranking input (a tiebreaker among relevant results, not a magic lever — the HELPFUL-CONTENT-grade caveat), and INP's bigger payoff is usually conversion, not rank — a page that responds in 150ms keeps users a frustrating one doesn't, so INP is UX-and-CRO work that happens to also be an SEO signal.

When it matters

INP matters most on interactive, JavaScript-heavy experiences — e-commerce filters and carts, configurators, single-page apps, anything where users tap repeatedly and the main thread is busy — and as the responsiveness half of the page-experience signal Google measures from real field data. It matters as a conversion lever first (sluggish interactions cost completions) and a ranking tiebreaker second. The discipline is field-data measurement at the 75th percentile (real users, not lab scores), JavaScript-execution discipline as the primary fix (long tasks broken up, third-party weight controlled), and INP treated as the UX-and-CRO investment it mostly is, with the SEO benefit as the bonus.

Worked example. A retailer's product-listing pages pass the old FID metric perfectly yet feel awful in use, and the March 2024 switch to INP finally measures the problem the team's customers had been reporting: filtering by size or color takes 600-900ms to visibly respond (poor INP) because each tap fires a heavy synchronous handler that re-runs layout across a huge DOM while third-party scripts hog the main thread. The fix is JavaScript-execution discipline, not a new framework: the filter handlers get broken into smaller tasks that yield to the main thread, non-urgent work (analytics beacons, recommendation refresh) is deferred off the interaction path, two heavy third-party tags are loaded lazily, and the DOM the filter touches is trimmed. Field INP drops to 180ms at the 75th percentile (good), and the payoff shows up where it matters most - not in a ranking jump (Core Web Vitals are a modest tiebreaker) but in conversion: filter-to-product-view rate rises and listing-page bounce falls, because the page now answers taps in the time a frustrated thumb expects. FID had certified a page that froze on every interaction after the first; INP measured the experience the customers actually had.

Failure modes to watch. Optimizing for lab scores when INP is a 75th-percentile field metric on real devices; treating it as a big ranking lever rather than a modest tiebreaker and a real conversion lever; passing FID and assuming responsiveness was fine (FID measured only the first interaction's delay); third-party script weight left unbudgeted on the main thread; and heavy synchronous event handlers freezing every interaction after the first.

Synonyms & antonyms

Synonyms

interaction to next paintINPresponsiveness vital

Antonyms

First Input Delay (the metric it replaced)unresponsive UI

Origin & history

Google introduced INP as an experimental metric in 2022, gave a long migration runway, and promoted it to a Core Web Vital on March 12, 2024, retiring First Input Delay - the upgrade from 'how fast did the first tap start processing' to 'how responsive is the whole page', measured from real-user field data.

Etymology: source.

Usage trends

Search interest for this term over the last five years:

View interest-over-time on Google Trends →

Common questions

What is INP?: The Core Web Vital for responsiveness — measuring the delay from a user interaction (tap, click, key) to the next visual update, reported near the worst across a visit; good is 200ms or less at the 75th percentile.
When did INP replace FID?: March 12, 2024 — INP became a Core Web Vital replacing First Input Delay, because FID measured only the first interaction's input delay while INP covers all interactions and the full response lifecycle.
How do you improve INP?: Break up long JavaScript tasks, reduce synchronous work in event handlers, trim and defer third-party scripts, and minimize the DOM and layout work each interaction triggers — main-thread discipline is the core fix.

Related tools & calculators

toolSEO audit tool
toolKeyword-prominence checker

Resources & people to follow

referenceweb.dev — INP becomes a Core Web Vital (March 12)
referenceChrome UX Report field-data thresholds
referenceRGM analysis — field data at p75, JavaScript discipline as the fix; INP is CRO that doubles as an SEO signal

Curated, non-competitor resources verified per term.

Related training

modulePerformance marketing

Disciplines

Areas of marketing where interaction to next paint (inp) is a core concern:

Performance marketingGrowth strategy

Sources

trendsGoogle Trends — "interaction to next paint"