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Outbyte Driver Updater FREEScan for outdated or missing drivers - takes under a minuteDriver Scan →Outbyte PC Repair FREEClear out junk files and repair common Windows errorsFree Scan →First Contentful Paint (FCP) measures how long a page takes to show its first eligible content after navigation begins. A good FCP is 1.8 seconds or less at the 75th percentile, assessed separately for mobile and desktop. It is an early signal that something appeared—not proof that the page’s main content is ready.
What is FCP?
First Contentful Paint is the elapsed time from the start of a navigation until the browser paints its first content. Eligible content includes text, images (including CSS background images), SVG elements, and non-white canvas; MDN also lists video. Text can count while its webfont is still loading. Content inside an iframe is excluded from the parent page’s FCP measurement. web.dev’s FCP guide and MDN’s definition describe the metric and its boundaries.
FCP answers whether anything has appeared, not whether the whole page has loaded. A small header, for example, can paint quickly while the main article or product image remains delayed. Largest Contentful Paint (LCP) measures when the largest visible content element is rendered, so it helps answer a different question about the page’s main content. web.dev’s LCP guide explains that metric.
FCP timing can include more than browser rendering: previous-page unload time, connection setup, redirects, and server time to first byte (TTFB) can all affect the result. That is one reason measurements can vary across visits and differ between field data and lab runs.
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What is a good FCP score?
web.dev’s FCP guidance, updated October 19, 2022, classifies an FCP of 1.8 seconds or less as good and a value greater than 3.0 seconds as poor. Results between those thresholds need improvement. These are field-performance thresholds; do not substitute Lighthouse’s lab-specific score bands for them. See web.dev’s FCP thresholds and guidance.
Assess the 75th percentile of page loads, and separate mobile from desktop. A single run or overall average can hide the slower experiences a substantial share of visitors encounter. When reporting a number, identify whether it is field or lab data, whether it is page-level or origin-level, which device segment it represents, and whether it is a percentile or a single test result.
How to measure FCP
Use field data to understand what real visitors experience and lab tools to investigate likely causes. The two views answer different questions: field measurements include real devices and networks, while lab runs provide more controlled, repeatable diagnostics. Chrome’s Lighthouse documentation describes lab measurement and diagnostics; the current PageSpeed Insights product combines CrUX field data with Lighthouse lab data. The available PageSpeed Insights API v4 documentation is deprecated, so it should not be used as a guide to current API parameters or interface behavior.
Check field performance
Open PageSpeed Insights for the page you want to evaluate and review the available real-user data. Chrome User Experience Report (CrUX) data reflects visitors’ actual environments, including their devices and networks; it may not be available for every page or site. Where page-level data is unavailable, origin-level data describes the site origin rather than that specific URL. Keep that distinction in mind when diagnosing one page.
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Run a lab audit
Use Lighthouse in Chrome DevTools or through PageSpeed Insights to run a controlled test and inspect FCP alongside the audit’s diagnostics and opportunities. Keep test conditions consistent when comparing runs, especially device and network settings. A lab result can help locate a likely bottleneck, but it does not establish that field performance improved; check field data again after the change.
Measure in code
The Paint Timing API exposes a first-contentful-paint entry that can be observed with PerformanceObserver. For production monitoring, the web-vitals JavaScript library handles several edge cases where possible. A raw API entry is not automatically a valid page-visit FCP: measurements need to account for background-tab visits, back-forward cache restores, and prerender activation timing. Cross-origin iframe paint timing may not be available to the parent page, and the web-vitals library does not resolve that limitation. See web.dev’s FCP measurement guidance.
How to improve FCP
Start with the specific page’s Lighthouse opportunities and diagnostics rather than applying every optimization indiscriminately. FCP can be delayed by server response and navigation overhead as well as rendering work, so first identify which part of the path is responsible.
Reduce delays before the first render
- Address slow server response: Investigate TTFB and the work required to produce the page. Avoid unnecessary redirects, which add navigation time before the browser can render content.
- Remove render-blocking work: Review CSS and JavaScript that must be fetched or processed before the browser can paint. Defer nonessential JavaScript and reduce render-blocking resources where the page’s requirements allow.
- Trim CSS and JavaScript: Minify CSS, remove unused CSS, and remove or defer unused JavaScript that contributes to early loading.
Prioritize the resources needed early
- Preload only key requests: Preload resources that are genuinely needed early in rendering; indiscriminate preloading can compete with other important downloads.
- Reduce network work: Where diagnostics point to it, reduce large payloads, request counts, and critical request depth. Use efficient caching for static assets so repeat visits can reuse them.
- Keep text visible during font loading: Configure font behavior so text does not remain invisible while a webfont is pending.
Use the audit evidence and verify the result
If the audit indicates that the browser is spending time on a large DOM or failing to prioritize visible content, inspect the page structure and what is delivered above the fold. Make a targeted change, rerun the lab test under comparable conditions, and then check field performance over time. These techniques are diagnostic directions, not guaranteed fixes; the useful change depends on the bottleneck on that page.
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