First Input Delay (FID) Explained

Learn How To Improve FID Scores & Ace Core Web Vitals Metrics

By
Rick Bucich

First Input Delay (FID) is a performance indicator that measures the time between a user’s input and the screen responding to that input. It is one of the key metrics in Google’s Core Web Vitals update and affects your search engine rankings.

It’s also known as First Input Latency or First User Vision. While it might sound like an obscure technical measurement, FID is an important indicator of how responsive and helpful your web pages will be for users.

Current mobile device usage patterns, the need for a fast-loading website, and the increasing attention to performance indicators have prompted Google to introduce and make FID a vital metric to track and optimize.  

This blog post will give you everything you need to know about FID, what it means for your web pages, and how you can optimize your web pages for fast response times.

What Is First Input Delay (FID)?

First input delay, also called first input latency, refers to the amount of time between when a user takes an action and when that action is reflected on the screen.

A higher first input delay can have a big impact on usability because it can make users feel like the website is unresponsive.

A user might make an input expecting something to happen, but if the web page takes too long to respond, that user might become frustrated and abandon the website. First Input Delay is the amount of time between the user’s first tap and when the web page responds to that tap. If a user taps the web page and waits 2 seconds for something to happen, the first input delay is 2 seconds.

FID is one of the Core Web Vitals metrics. Make sure you optimize your web pages for Largest Content Paint (LCP) and Cumulative Layout Shifts (CLS) as well.

How is First Input Delay (FID) different from Time to Interactive?

The Time To Interactive (TTI) metric measures how long it takes for a web page to become fully interactive after a user launches it. This is an important metric because it shows whether the web page is easy to navigate and if users can get to the content they want quickly.

The FID metric, on the other hand, measures how quickly a web page responds to a user’s first click or tap. This is a different kind of responsiveness, but it’s still important because a slow response time can lead to a poor user experience.

However, it’s important to remember that the FID metric is mostly related to the time it takes for a page to load, while the Time to Interactive metric is related to how long it takes for the page to fully load and become interactive.

How is First Input Delay (FID) different from Interaction to Next Paint (INP)?

FID measures how quickly a page responds to a user’s input whereas Interaction to Next Paint (INP) measures how quickly the next screen in a user’s flow loads after an action.

FID measures interactiveness while INP focuses on responsiveness. Google has announced that INP will replace FID as a Core Web Vitals metric. While INP is still being tested, it was introduced to fill in the gaps that FID presented.

First Input Delay (FID) only accounts for the first interaction. It measures only input delay, not the processing time of event handlers or the delay in displaying the next frame. In contrast, INP considers all page interactions.

This update means that while it is essential to measure and optimize your web pages for FID, you should slowly shift and start measuring INP as a Core Web Vitals metric as well. Read our article on how to optimize your web pages for INP.

First Input Delay v/s Total Blocking Time (TBT)

Total Blocking Time (TBT) is the amount of time a computer system is unavailable for service. It is the sum of the blocking time of all the nodes in the system. This is an important metric because it shows how much time the system is unavailable for users.


First Input Delay (FID) is the time it takes for the first input to be received by the server.


FID is important for web applications as it measures the responsiveness of the application. TBT is more important for systems that are composed of multiple nodes as it measures the amount of time the system is unavailable for service.

How Does First Input Delay (FID) Impact SEO?

First Input Delay (FID) is an important factor for SEO because it can impact the user experience on a website. If a website has a high FID, it can cause the user to wait a long time for the website to load. This can cause the user to leave the website before they have a chance to see the content. This can impact the website's ranking in search engine results pages.


If your web pages have good FID scores then your pages will generally load faster, leading to a better user experience and improved engagement. You will also be rewarded with better search engine rankings as faster-loading pages are favored by Google and other search engines.

First Input Delay (FID) Advantages

1. First Input Delay is much more actionable than Time to Interactive as it can be used to identify and diagnose issues with your app’s performance.

2. FID is also easier for developers to implement than other performance indicators like UI Response Time or Frame Rate.

First Input Delay (FID) Disadvantages

1. It doesn’t account for network conditions.

First input delay measures the time between a user tap and when the web page responds on screen, it doesn’t take into account any time that might have elapsed while waiting for data from a remote server.

If your web page requires a round trip from your server before displaying content to users, it could significantly increase the time they have to wait before seeing their response appear on the screen.

This could result in an increase in first input delay that isn’t representative of how responsive your web page really is under normal network conditions.

2. It doesn’t account for pre-loading content.

If your web page is retrieving data from a remote server, it may display some content while waiting for the full response to be retrieved. This could result in an increase in first input delay and give false results.

How to Measure First Input Delay (FID)?

FID measures how quickly a page responds to a user’s input. Google’s official documentation recommends sites should strive to have a First Input Delay of 100 milliseconds or less.

If you would like to ensure that most of your users are hitting this target, a good threshold to measure would be the 75th percentile of mobile and desktop page loads.

First Input Delay metrics
First Input Delay Metrics

FID is often associated with the “loading” page of a website. A “loading” page is a page that is currently being loaded by a user’s browser, either through a click or automatically by the browser.

A low FID score will show that your content is easy to reach and quick to load. This can help you retain users and improve your ranking in the Google SERPs.

Tools to Help Measure First Input Delay

1. Google Developer Tools: Google’s Chrome browser has a built-in developer tool that can be used to measure FID. This allows you to see how long it takes for a web page to load and become interactive. The developer tool also allows you to see how many resources are being loaded by the web page and whether they are blocked or not.

2. Google Analytics is a free service that can be used to collect data about website traffic, including FID data. As of this writing, the latest version of Google Analytics is v4 and it can be used on any website that uses HTML5, CSS3, and JavaScript.

3. Google’s Core Web Vitals Metric is an analytics platform developed by Google for developers (or anyone else) who want a simple way to gather data about their page performance without having to write code or learn complex analytics tools like Google Analytics or Flurry. It has some limitations compared with other analytics platforms but it’s free and easy to set up, so it might be worth giving it a try if you need something simple but effective. You can see your Core Web Vitals score in your Google Search Console reports under the ‘Performance’ section.

How to Fix First Input Delay & Optimize your Web Pages for FID?

1. Reduce the size of your images: Small images, as well as images that aren’t necessary for the content, can add unnecessary weight to your page. Images account for about 60% of the data transferred, so if you can reduce the size of your images without losing quality, you can reduce your page size and speed up your page.

2. Use a Content Delivery Network (CDN): A CDN is a server that stores your website’s content and distributes it across the globe. A CDN allows your website’s content to be delivered quickly because it’s being hosted across the world, not just in your region.

3. Optimize your code: Code that isn’t optimized can slow down your website. You can use tools that analyze your code and tell you where you can make improvements.

4. Leverage browser caching: Browser caching allows your browser to download and “remember” the content of your website. It saves a lot of bandwidth and time.

5. Use asynchronous loading: Asynchronous loading allows you to load your content asynchronously. This means that users will see something on their screen while the rest of the page loads.

Track Site-Wide FID Scores & Automate Optimization With Quattr

The current process of optimizing web pages for FID only allows you to optimize the scores for one web page at a time. This can be a challenge if you have a website with thousands of web pages. Existing tools do not allow you to optimize and track your FID across your entire website.

The Quattr platform addresses the shortcomings of the current process and helps you optimize your site to improve overall page experience and FID Scores. You can use the Quattr platform to view FID scores for each page of your website all at once. You can also filter pages based on whether the FID score is Good, Needs Improvement, or Poor. Quattr also lets you compare FID, and other Core Web Vital scores against your competitors in one view.

Check First Input Delay (FID), LCP, and CLS scores for competitors and evaluate the overall Page Experience.
Compare Core Web Vitals against your competitors in Quattr

If you are looking to optimize your FID scores and improve the page experience of your entire website then Quattr’s Usability Recommendations is here to help. The performance dashboard within usability recommendations gives you a list of prioritized recommendations and performance improvements you can make across your entire site.

Usability Recommendations by the Quattr Platform
Usability Recommendations by the Quattr Platform

This list is ranked based on what key pages you should focus on and aligns optimization efforts with business metrics like clicks and conversions so that you can measure the benefits of your efforts.

Continue to Optimize First Input Delay

First Input Delay is an important metric that measures how quickly your pages respond to a user's input. While Google may be phasing out this metric in the future, currently it is key to your Core Web Vital scores.

It is important to understand how it's calculated and what impacts it has on your users. In order to improve your FID, it's important to optimize your website's images, use a content delivery network, optimize your code, and use asynchronous loading to ensure your pages load quickly.

While the current optimization tools only allow you to track and optimize FID scores per web page, Quattr can help scale and automate your optimization efforts.

About The Author

Rick Bucich

Rick is the Customer Success Manager at Quattr and got involved in SEO by accident 20 years ago while working at a small startup. At Quattr, Rick brings his years of experience in SEO and translates it into actionable recommendations that ensure sustained organic growth for our customers. Rick writes about how to optimize and enhance websites for search engines.

About Quattr

Quattr is an innovative and fast-growing venture-backed company based in Palo Alto, California USA. We are a Delaware corporation that has raised over $7M in venture capital. Quattr's AI-first platform evaluates like search engines to find opportunities across content, experience, and discoverability. A team of growth concierge analyze your data and recommends the top improvements to make for faster organic traffic growth. Growth-driven brands trust Quattr and are seeing sustained traffic growth.

Optimize your FID Scores with Quattr today!

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