Sum of all time periods between FCP and Time to Interactive, when task length exceeded 50ms, expressed in milliseconds

Optimized images load faster and consume less cellular data

Some third-party scripts may contain known security vulnerabilities that are easily identified and exploited by attackers

Cumulative Layout Shift measures the movement of visible elements within the viewport

Lists the longest tasks on the main thread, useful for identifying worst contributors to input delay

Reduce unused rules from stylesheets and defer CSS not used for above-the-fold content to decrease bytes consumed by network activity

Text-based resources should be served with compression (gzip, deflate or brotli) to minimize total network bytes

Third-party code can significantly impact load performance. Limit the number of redundant third-party providers and try to load third-party code after your page has primarily finished loading

A large DOM will increase memory usage, cause longer [style calculations](https://developers.google.com/web/fundamentals/performance/rendering/reduce-the-scope-and-complexity-of-style-calculations), and produce costly [layout reflows](https://developers.google.com/speed/articles/reflow)

A long cache lifetime can speed up repeat visits to your page

To set budgets for the quantity and size of page resources, add a budget.json file

Large network payloads cost users real money and are highly correlated with long load times

Server latencies can impact web performance. If the server latency of an origin is high, it's an indication the server is overloaded or has poor backend performance

Largest Contentful Paint marks the time at which the largest text or image is painted

Reduce unused JavaScript and defer loading scripts until they are required to decrease bytes consumed by network activity

The Critical Request Chains below show you what resources are loaded with a high priority. Consider reducing the length of chains, reducing the download size of resources, or deferring the download of unnecessary resources to improve page load

These DOM elements contribute most to the CLS of the page.

The maximum potential First Input Delay that your users could experience is the duration of the longest task

This is the largest contentful element painted within the viewport

Serve images that are appropriately-sized to save cellular data and improve load time

First Meaningful Paint measures when the primary content of a page is visible

Network round trip times (RTT) have a large impact on performance. If the RTT to an origin is high, it's an indication that servers closer to the user could improve performance

Speed Index shows how quickly the contents of a page are visibly populated

Time to interactive is the amount of time it takes for the page to become fully interactive

Consider reducing the time spent parsing, compiling, and executing JS. You may find delivering smaller JS payloads helps with this

First Contentful Paint marks the time at which the first text or image is painted

Consider reducing the time spent parsing, compiling and executing JS. You may find delivering smaller JS payloads helps with this

Resources are blocking the first paint of your page. Consider delivering critical JS/CSS inline and deferring all non-critical JS/styles

Image formats like WebP and AVIF often provide better compression than PNG or JPEG, which means faster downloads and less data consumption

Keep the server response time for the main document short because all other requests depend on it

Large network payloads cost users real money and are highly correlated with long load times

The Critical Request Chains below show you what resources are loaded with a high priority. Consider reducing the length of chains, reducing the download size of resources, or deferring the download of unnecessary resources to improve page load

The maximum potential First Input Delay that your users could experience is the duration of the longest task

Largest Contentful Paint marks the time at which the largest text or image is painted

Reduce unused rules from stylesheets and defer CSS not used for above-the-fold content to decrease bytes consumed by network activity

Consider reducing the time spent parsing, compiling and executing JS. You may find delivering smaller JS payloads helps with this

Network round trip times (RTT) have a large impact on performance. If the RTT to an origin is high, it's an indication that servers closer to the user could improve performance

Sum of all time periods between FCP and Time to Interactive, when task length exceeded 50ms, expressed in milliseconds

First Meaningful Paint measures when the primary content of a page is visible

Resources are blocking the first paint of your page. Consider delivering critical JS/CSS inline and deferring all non-critical JS/styles

Text-based resources should be served with compression (gzip, deflate or brotli) to minimize total network bytes

Time to interactive is the amount of time it takes for the page to become fully interactive

Interactive elements like buttons and links should be large enough (48x48px), and have enough space around them, to be easy enough to tap without overlapping onto other elements

These DOM elements contribute most to the CLS of the page.

First Contentful Paint marks the time at which the first text or image is painted

Reduce unused JavaScript and defer loading scripts until they are required to decrease bytes consumed by network activity

Consider reducing the time spent parsing, compiling, and executing JS. You may find delivering smaller JS payloads helps with this

A large DOM will increase memory usage, cause longer [style calculations](https://developers.google.com/web/fundamentals/performance/rendering/reduce-the-scope-and-complexity-of-style-calculations), and produce costly [layout reflows](https://developers.google.com/speed/articles/reflow)

First Contentful Paint 3G marks the time at which the first text or image is painted while on a 3G network

Keep the server response time for the main document short because all other requests depend on it

A long cache lifetime can speed up repeat visits to your page

Consider lazy-loading offscreen and hidden images after all critical resources have finished loading to lower time to interactive

To set budgets for the quantity and size of page resources, add a budget.json file

Some third-party scripts may contain known security vulnerabilities that are easily identified and exploited by attackers

Serve images that are appropriately-sized to save cellular data and improve load time

Third-party code can significantly impact load performance. Limit the number of redundant third-party providers and try to load third-party code after your page has primarily finished loading

Lists the longest tasks on the main thread, useful for identifying worst contributors to input delay

Cumulative Layout Shift measures the movement of visible elements within the viewport

Server latencies can impact web performance. If the server latency of an origin is high, it's an indication the server is overloaded or has poor backend performance

Speed Index shows how quickly the contents of a page are visibly populated

Image formats like WebP and AVIF often provide better compression than PNG or JPEG, which means faster downloads and less data consumption

This is the largest contentful element painted within the viewport

Font sizes less than 12px are too small to be legible and require mobile visitors to “pinch to zoom” in order to read. Strive to have >60% of page text ≥12px