FID / INP Checker

INP (Interaction to Next Paint) measures the latency of all interactions on a page throughout its lifetime. It replaced FID as a Core Web Vital in March 2024. Good INP is under 200ms.

FID (First Input Delay) measured only the delay from the first user interaction. It was deprecated in March 2024 and replaced by INP which measures all interactions.

Break up long JavaScript tasks, minimize DOM size, reduce third-party script impact, avoid forced synchronous layouts, and use CSS transitions instead of JS animations.

Yes, the FID / INP Checker is 100% free with no registration, no hidden fees, and no usage limits. All processing happens locally in your browser, ensuring complete privacy.

Absolutely. The FID / INP Checker processes everything client-side in your browser. No data is uploaded to or stored on any server. Your content remains private on your device at all times.

Yes, the FID / INP Checker is fully responsive and works on smartphones and tablets. You can use it on any device with a modern web browser -- no app download required.

No account or registration is needed. Simply open the FID / INP Checker in your browser and start using it immediately. There are no sign-up walls or usage restrictions.

Yes, the FID / INP Checker is built following current Google Search guidelines and best practices. We regularly update the tool to reflect changes in search engine requirements.

The FID / INP Checker works in all modern browsers including Chrome, Firefox, Safari, Edge, and Opera. For the best experience, use the latest version of your preferred browser.

Google rates INP (Interaction to Next Paint) in three bands measured in milliseconds: Good is under 200 ms, Needs Improvement is 200 to 500 ms, and Poor is anything above 500 ms. To pass the Core Web Vitals assessment, the 75th percentile of your real users should fall in the Good band, meaning at least three out of four interactions respond in under 200 ms. FID used a more lenient scale because it only measured the first interaction: Good under 100 ms, Needs Improvement 100 to 300 ms, and Poor above 300 ms. Since INP captures the worst interaction across the whole page lifetime, it is harder to pass and a more honest reflection of how responsive a page feels. Paste a value from PageSpeed Insights into this checker to see exactly which band you land in.

FID (First Input Delay) only measured the delay before the browser began processing the very first interaction after load, and even then it captured input delay alone, not the time to actually update the screen. That made it easy to pass: the first tap often lands before the main thread gets busy, so many slow pages scored well. INP fixes both blind spots. It observes every click, tap, and keypress for the entire time a page is open, measures the full latency from input to the next visible paint, and reports the worst one. The result reflects sustained responsiveness a real visitor experiences, not a single lucky snapshot. Google made INP an official Core Web Vital in March 2024, retiring FID. This tool still reports FID for legacy comparison while putting INP front and centre, so you can check how a page measures up under the current standard.

The two numbers answer different questions. This tool's live measurement attaches a PerformanceObserver to your current tab and records the latency of the interactions you perform right now, on your device, network, and CPU. It reflects exactly one session, which is ideal for sanity-checking a development build or your own machine. PageSpeed Insights, by contrast, reports field data from the Chrome User Experience Report, aggregating real visits over the trailing 28 days at the 75th percentile across many devices and conditions. A fast laptop will often show a better live number than the field data, because slower phones and busy networks drag the real-world figure up. Treat the live reading as a quick diagnostic and the field score as the verdict that affects search. Use both paths in this checker: measure live, then paste the PSI value to rate it.

You do not need Chrome DevTools or the web-vitals library to get a real reading. Open this checker, click Start Measuring, then interact with the page exactly as a visitor would: click buttons, type into inputs, and scroll. Behind the scenes it attaches a PerformanceObserver to event and first-input timing entries, records the latency of each interaction, and reports the maximum INP it sees plus the first input's FID. Because it reads standard browser timing data from your own session, nothing is uploaded and the measurement is genuinely live rather than simulated. This is the quickest way to confirm a fix worked before a release reaches real users. For field data representative of all visitors, follow the built-in link to PageSpeed Insights and paste the returned value back into the tool to get an instant rating.

High INP almost always traces back to the main thread being blocked when a user interacts. The usual culprits are long JavaScript tasks over 50 ms, heavy work running directly inside click or keydown handlers, large DOM trees that make every style and layout recalculation expensive, third-party scripts, forced synchronous layouts, and JavaScript-driven animations that could run on the compositor instead. To find the offender, use this tool's live measurement and interact with each element in turn; the reported maximum INP rises on the interaction that lags, pointing you at the handler to investigate. Common fixes include breaking long tasks up with setTimeout, requestIdleCallback, or scheduler.yield(), keeping the DOM under roughly 1,500 nodes, deferring non-critical scripts, and preferring CSS transitions over JavaScript animation. Measure, apply one change, then re-measure here to confirm the interaction got faster.