Do HTML Comments Affect Performance

HTML comments provide information about the code, such as why a certain part of the code was written or what it does. However, they can also affect the performance of a website.

The most common reason HTML comments affect performance is because these comments are not removed from the code before it’s published. While this may seem like a minor issue, these comments can negatively impact your website’s performance by adding unnecessary weight to your site’s load time.

Read on to learn more about whether HTML comments substantially impact your website and what you can do about it.

Web Developers Use HTML Comments for Documentation

Web developers use HTML comments because they want their code to be easily readable by others. When you look at a piece of code, and it’s all in one big block of text with no breaks or spaces, it can be hard to figure out what each part does. That’s where HTML comments come in—they let you break up the code into smaller chunks, making it easier for others (or even you) to understand each part.

HTML comments also allow you to add notes about why certain things are done in certain ways. This isn’t just helpful for other people who might be reading your code—it can also help you remember why you did something if your memory gets fuzzy later on down the road!

Other reasons why developers use HTML comments are:

  • To provide information about the document, such as the creation date or author.
  • To provide additional information about the document’s structure, such as the purpose of each heading.
  • To provide information about how to use the document, such as navigating through it or printing it.

The website browser will disregard any HTML comments. No user will see it in their browser, and it won’t alter the appearance of your site in any way.

html comments to show sections of HTML code
HTML comments can be very useful in larger HTML files. With them, you can easily visually split different sections of HTML code, so you can find them faster.

How HTML Comments Affect the Performance of Your Website

The most obvious negative effect of HTML comments is that they make your site slower. This is because web browsers look at HTML comments and think, “hmm… maybe this site is trying to tell me something.” So they must spend time processing them and deciding whether or not they’re important before they can get down to business with the rest of your page.

When you consider how long it takes for even a single second of delay on a website (let alone several seconds), this can mean the difference between people staying on your site long enough to read your content and click through to other pages or leaving immediately because their eyes glaze over from waiting too long for something to load.

Here are the adverse effects of using HTML comments:

  • They can slow down website loading times. It takes longer for browsers to load pages with HTML comments than without them because they need to parse through more information before displaying the page.
  • These comments can confuse search engines, which may not index them correctly. This can lead to lower search engine rankings for your website and fewer visitors who might otherwise find your site through organic search results.
  • They take up space on your site. Even if you don’t see them, they’re there and taking up bandwidth. This is also why it affects your site’s responsiveness and quickness. More bytes lead to more traffic, so if you’re running an eCommerce site or any other site with high traffic, this can be a big problem.
This is an example of a comment that shouldn’t be deployed. The only difference between the comment and the IMG tag below is the SRC of the image and doesn’t help anyone that will be editing the HTML after.

Minimizing the Impact of HTML Comments

Suppose you’re using HTML comments on your website. In that case, you may wonder how to minimize its impact on your website’s responsiveness.

The short answer is: Don’t use them at all. But if you must use them, you can do a few things to ensure they don’t slow down your site’s performance.

  • Get rid of any comments that aren’t necessary for running your code or debugging purposes. If you have no reason to keep them around, get rid of them!
  • Make sure they’re concise and relevant. If you absolutely must keep some comments in your code, try making them as small as possible so they don’t take up too much space or slow down loading times too much.
  • Keep HTML comments on your local machine and/or your development environment. Instead of using HTML comments on your site’s staging and production versions, just keep them on your local or dev station.

Another common practice for keeping your HTML files light is to avoid in-line styling. Other than performance, separating HTML and CSS has multiple benefits, which I’ve discussed in a complete guide.

Enhancing Your Website’s Responsiveness

The responsiveness of your website will be significantly enhanced by eliminating or minimizing the use of HTML comments. However, you can also perform the following to help your website respond faster:

  • Optimize the page for mobile devices by removing unnecessary content and optimizing images. If a user is on a mobile device, they won’t want to scroll through a bunch of text or look at big photos—they’ll want to get straight to what they need.
  • Make sure that your pages load quickly. If you’re using images in your content, ensure their size is manageable and appropriate for their placement.
  • Check to see that all of the links are functioning correctly. Ensure that the primary navigation bar at the top of the site provides access to all of the site’s pages.
  • Make sure that each button can be clicked with ease. In this regard, you must remember to add padding around them.
  • Use CSS media queries, so the site will automatically change how it looks based on what type of device is being used. This is especially important for tablets because they require different layouts than phones due to their larger screens.

Writing efficient code is a highly sought after skill that many beginner developers lack. And it directly affects their ability to compete in the market and command high salaries. I’ve written about the reasons web developers don’t make enough money in a complete guide. Read it to learn how you can increase your income as a web developer.

Sometimes it is useful to show what certain scripts mean. Don’t worry to leave such comments in the HTML code. Optimizing the size of a single image has a much larger effect on the speed of loading your website than removing all the useful comments in HTML code.


HTML comments are perfectly acceptable to use in almost all circumstances. On the other hand, too much of something can have unintended and undesirable effects. Similarly, an excessive amount of HTML comments might slow down a website’s performance. It may slow down the loading speed and may have a significant effect on your SEO ranking.

Therefore, if you want your website to operate and rank better, it is strongly advised that you eliminate all unnecessary comments, particularly those that are redundant.