Have you ever come across a file with a really strange extension? And there is no way that you can figure out what kind of file it is? Well, we often come across so many types of files. Sometimes, we know what those extensions define. But, more often than not, we don’t. And that’s completely natural, given that there are thousands of file formats.

Let’s say, a file has the extension doc or docx (characters following the last period in the file name), you know that you will need Microsoft Office or one of its alternative productivity suites, such as Google Doc, to view as well as edit it.

But what if the file extension is one you’ve never seen before? Or maybe one for which your computer can’t open files as the can’t find the right software? Or even worse, the files have no extensions at all?

Working on a computer

In this article we’ll guide you through how to check a file for extension online know what type of file extension you are dealing with. And of course, we’ll also talk about the numerous methods you can use to open a file with no extension, or unknown extension.

What is a file extension?

Before we begin discussing about how we can check for a file extension online, or how to identify the file extension in computer, let’s clear our basics. What is a file extension exactly?

The file extension name is a suffix that is appended to the end of a file name to indicate what type of file it is. The extensions of various file formats are very different.

Image files, for example, can have extensions such as JPG, JPEG, and PNG. Similarly, different extensions indicate the file type in other document files. The extensions are prefixed by a dot, such as .pdf, .xls, and .doc for PDF, Excel sheet, and Word Document, respectively. MP4, MKV, AVI, FLV, and other video file extensions exist.

But the file extension list does not end here. That is what makes it so much more difficult for all of us to identify the type of any file with ease.

But how do I get to know what type of file it is?

There are different types of file formats that exist, which we are barely aware of. Maybe if we had this file extension list of all these formats, we would be able to identify which is which. But that would be a vast ever-growing database.

File Formats

New file extensions are continuously being generated with the advancement of technology. At the same time if you are not tech- savvy, it might make it a lot more difficult for you to handle the database and keep track of the types of file extensions.

So, instead maybe you can do a little research on the type of file you’re handling. You would need to check the file extension name, that is, the characters succeeding the period in the file name. And you could dig up a little more on the that file extension on the internet. Maybe that would be sufficient. But again, even for that, you would have to be tech- savvy.

What if there’s a file without an extension? How do we determine what type of file it is?

What if I tell you, that you don’t worry about any of these at all anymore? You could use our File Type Checker tool which is super simple to use, and our tool will return the results right away. Sounds good, right? Let me elaborate.

File Type Checker

About our tool

Our tool is called the File Type Checker. It is absolutely free to use, and 100% online. It has a very simple user interface, and all you need to do is, upload the file you want to check the type of. It could also be a file without any extension.

This File Type Checker tool is completely platform independent. It works on all Operating systems and can be used without any downloads at all.

We place a high value on the privacy of our visitors. Your files are not uploaded because we use cloud storage. As a result, there is no risk of a data leak. Your information is by all means, safe and secure with us.

At the same time, you not only learn the file type, but you also learn about complex topics such as the MIME type and other possible extensions.

How to use the File Type Checker tool

How to open a file with no extension or unknown extension?

There are multiple methods you can adopt in order to open a file which has no extension, or an uncommon one.

1. When we don’t know what file type we are dealing with, we always try to open the file in our computers, right? But if the file is of an unidentified or uncommon type, a message is displayed which says, “How do you want to open this type of file?”.

At the same time, it gives you the options from which you can choose. But often when the pc cannot identify the type of file format, it does not give us the options. The first thing you need to do is, do not freak out, no matter what.

2. The next step you need to follow is, to conduct a little bit of research about the file type. You can use our File Type Checker to conduct research on the file, and identify the file extension. You can also surf the internet instead, and check out various websites for more details.

Download button

Now, these are the three methods you can follow-

  • When Windows asks you how you would like to open the file, select “Look for an app in the Store” from the menu. The Microsoft Store appears, displaying all of the apps that can open this particular file. Install one of them and see if that works for you.
  • The best approach to learn about a new file format is to search online, and the best location to do so is the Filext database. It’s a large database with more than 50,000 file extensions. Search the file you need more details on, and the website will provide you with it.
  • Finally, if you still can’t figure out how to access the unfamiliar file type, use a search engine like Google or Bing to search for answers. You should be able to determine what type of file your unknown file is, how it is used, and what applications can open it.


We hope that with this article, you now have the basic idea of what file extensions are. We have also explained that you don’t necessarily need to know everything about how to open various file types. Having a good, stable internet connection and a little thirst for knowledge will be enough.

But if you do want to know what the different file extensions are, you could check out our article on “What is a file type? What are common file extensions?”

You can research on the file types by yourselves on the internet, or you can use online tools like our File Type Checker to check the type of file.