Coding is one of the most important aspects of web development because you need to remember that your website is “read” by users as well as web crawlers. Whenever Google bots scan or indexes a site, it tries to understand the primary content of each page so that it can rank it appropriately. If there are multiple pages on the same site, and those pages appear identical, then the web crawler chooses the page that it thinks is the most complete and marks it as canonical. Since canonical pages play an integral role in indexing and ranking you need to understand how Google designates a canonical page and what can be done to help search engines mark canonical pages.

What is a Canonical Tag?

Web crawlers “read” your content based on the code you write for your website. A canonical tag, also known as "rel canonical," is basically a part of HTML code that helps search engines understand the main version of the website and check for duplicate or near-duplicate content. In short, the canonical tags help search engines like Google identify specific URLs that represent the master copy of a page.

Canonical tags are usually added in the section of a web page's HTML source code. To give you a general idea, here’s how a canonical tag appears in HTML code:

Why are Canonical Tags Important?

Duplicate content or identical pages on your website are a serious problem and can cause Google to devalue your website when determining rankings. If your website has a lot of duplicate content then web crawlers may find it difficult to index the webpage and may skip some of your unique content.

The biggest benefit of using canonical tags is that it helps resolve issues that arise because of identical or “duplicate” content. It serves a partial purpose because it lets search engines know which version of a URL to index so that it appears in search results.

In addition, if search engines cannot rank your webpage because of duplicate or near-duplicate content, then the algorithm may pick the wrong URL as the "original" and may select a version of your page that you don’t really want to show in the results page. Adding canonical tags to your website will tell Google and other search engines which version of a page they should index and rank.

Tips to use canonical tags

Canonical URLs are important because they help you deal with issues related to duplicate content that will affect the performance and ranking of your site in the long run. Here’s a look at some of the best practices you can follow while using canonical tags:

1. Use absolute URLs: Google web developers suggest that the best practice for canonical tags is not to use relative paths with the rel=“canonical” link element. Evidence suggests that when you use absolute URLs as opposed to relative paths it increases your chances of being interpreted correctly. For example:

Absolute URL:

Relative URL:

Always remember, when coding your website canonical tags should be referenced using absolute URLs.

2. Use lowercase URLs: Google web crawlers sometimes treat uppercase and lowercase URLs as two different URLs. When this happens, it is possible that the wrong version of your webpage will get indexed. To avoid this error you need to make sure to force lowercase URLs on your server. Once that is done you can go ahead and use lowercase URLs for your canonical tags.

3. Canonicalize your home-page: The most common duplicate issue occurs with homepage content since people may link to your homepage in many ways. Since you cannot control the path users follow to reach your home page the best way to resolve the issue of duplicate pages is to put a self-referential canonical tag on your homepage template.

4. Use the correct domain version: Effective use of canonical tags depends a lot on whether you use the correct domain name, whether it is HTTPS or HTTP. The mistake many developers make is that even though they switch to SSL, the normal use a non-SSL URL in the canonical tag. An incorrect domain version can confuse web crawlers and will affect the web results. Whenever you use a secure domain, make sure you use “href=“https://example.com” instead of simply “href=http://example.com.”

5. Avoid Setting Multiple Canonical URLs: Do not make the mistake of thinking that the more canonical tags you use the better. Using multiple canonical tags can cause confusion, especially if the tags are irrelevant. When you are writing the code for your webpage you need to make sure you sue a single canonical tag for each page otherwise Google may ignore pages with multiple irrelevant tags. You should take special care to ensure you do not include two canonical tags within your page's , even if you feel it will help to override defaults in some content management systems.

Conclusion:

Google clearly states that the canonical pages act as the main sources to evaluate the content and quality of a webpage. Since Google chooses the canonical page based on a number of factors, you need to explicitly designate a canonical page so that it becomes easier for the search engine to index your page.

Using canonical tags will not only help specify which URL you want people to see in the search engine results page but it will also help you get consolidated metrics for a specific piece of content on your website. It is important to note that even after you include canonical tags in your HTML code, Google might choose a different canonical page based on performance or content. You should consult an SEO expert or get in touch with the best web development company in your area to learn how to use canonical tags correctly so they you can get the most out of your site.