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.DOCX
Microsoft Word Open XML Document
Document
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7-Zip Archive
Archive
.AUTOCAD (DWG, DXF)
Drawing File
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.PDF
Portable Document Format
Document
.TXT
Plain Text File
Document
.OBJ (.OBJ)
Wavefront OBJ File
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.JSON
JavaScript Object Notation
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.CSV
Comma Separated Values
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.MDB
Microsoft Access Database
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PHP HTML
Programming
.STEP (.STP, .STEP)
Standard for the Exchange of Product Data
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.PSB
Photoshop Big
Image
File Guide
How to identify and open unknown file types
File extensions help your operating system and applications understand what kind of data a file contains. With FileTypes, you can search an extension, learn what it is used for, and find compatible software before opening the file.
Explore extensions
Search the extension
Enter a file extension such as PDF, DOCX, JPG, ZIP, or MP4.
Check compatible software
Find programs that can open, view, edit, or convert the file type.
Open files safely
Be careful with unknown files and scan suspicious downloads before opening them.
What You Can Do
File Extension Tools
Tools to identify file types, check compatibility, and find alternatives
Find Any File Type
Identify file extensions, learn what they are, and how to open them.
Explore extensionsSoftware Compatibility
Check which programs can open specific file types across platforms.
Check compatibilityFind Alternatives
Discover similar file formats with better compatibility and support.
View alternatives
FAQ
Frequently Asked Questions
Everything you need to know about file extensions
Common Questions
Everything you need to know about file extensions
A file extension is the suffix at the end of a file name (such as .pdf or .jpg) that identifies the file type and determines which programs can open it.
To open an unknown file, first identify its file extension. Once identified, you can use compatible software or convert the file to a supported format if necessary.
On Windows and macOS, file extensions are generally not case sensitive. However, on many Linux systems and web servers, file extensions can be case sensitive.
If a file won't open, make sure you are using the correct program for its file type. Updating the software, checking for file corruption, or converting the file may help.
Changing a file extension does not convert the file format and may cause the file to stop working. To properly change formats, use a file conversion tool designed for that file type.