What is the Difference Between HTM and HTML?


We come across many types of files while building webpages. The only way to differentiate between these files is their file name extensions. Web pages are the most common types of files found on web servers. The webpage’s standard file extensions are .htm and .html. Both these extensions are related to HTML, the basic language used for writing webpages. These extensions are usually used for webpages with static content.

Technically speaking, apart from the letter L, there is no difference between .htm and .html. .htm is sometimes used as a short form extension of an HTML file. For example, a file can be defined as “htmltemplate.htm instead of “htmltemplate.html”. The main advantage here is that Window 3 X and DOS based computers that prefer three character suffixes (.htm) over four characters (.html) may recognise this file name. But, the disadvantage is that the latest operating systems might have difficulty is recognising it as an html file. However, the existing servers give you the freedom to setup your default file name. Hence, the use of .htm over .html or vice versa, depends on user preference.

.htm files serve the same purpose as .html files. .html file extension was the original file extension for HTML pages running on Unix web servers. HTML files commonly seen with .html extensions can be created with WYSIWYG html editors, such as Adobe Dreamweaver, Adobe GoLive and Adobe ColdFusion Builder and are supported by all web browsers. While .htm file extension was created for Windows 3X and DOS based computers that do not understand extensions with more than three characters. This less common extension arose with the use of WYSIWYG html editors, like Expression Web, FrontPage and SharePoint and Mac html editors like Adobe Dreamweaver CS5, Adobe GoLive and Adobe ColdFusion.

File extensions help the operating system to identify the kind of data file it is dealing with and in identifying an appropriate program to read and edit it. At times, the computer is unable to open “unknown” file extensions that may not have the associated program installed to be able to open it. In such cases, html converter is required to convert .html/.htm extension files into other formats and vice versa.

Concisely, .htm and .html are both recognised as HTML files. The only difference between the two is that .htm is used as an alternate to .html by few servers that do not accept four character extensions. However, operating systems have advanced over years and now, they support long name too.

The following links will shed more light on the difference between .htm and .html file extensions.

  • .htm vs. .html: Detailed analysis the difference between the two extensions.
  • Htm and Html: Brief information on these extensions
  • File extensions: Details of all the file extensions including htm and html and how they work.