This reference lists commonly used file extensions categorized by purpose — essential for file management, troubleshooting, and software usage.
| Extension |
Type |
Usage Example |
.doc/.docx |
Microsoft Word |
Text documents, reports |
.xls/.xlsx |
Microsoft Excel |
Spreadsheets, data sheets |
.ppt/.pptx |
Microsoft PowerPoint |
Presentations |
.pdf |
Portable Document |
Cross-platform document format |
.txt |
Plain Text |
Simple notes, logs |
.odt/.ods/.odp |
OpenDocument |
LibreOffice formats |
.rtf |
Rich Text Format |
Text with basic formatting |
| Extension |
Type |
Usage Example |
.jpg/.jpeg |
Compressed Image |
Photos, web images |
.png |
Lossless Image |
Transparent images, screenshots |
.gif |
Animated Image |
Simple animations |
.bmp |
Bitmap Image |
Raw, uncompressed image |
.svg |
Vector Graphic |
Scalable logos, icons |
.webp |
Modern Web Image |
Compressed, smaller web images |
| Extension |
Type |
Usage Example |
.mp3 |
Audio |
Music, voice recordings |
.wav |
Audio (raw) |
High-quality sound |
.mp4 |
Video |
Video playback, compressed |
.mkv |
Video |
High-quality video, supports subtitles |
.avi |
Video |
Older format, larger size |
.flac |
Audio |
Lossless audio format |
| Extension |
Type |
Usage Example |
.zip |
Compressed Archive |
File compression (cross-platform) |
.rar |
Compressed Archive |
Requires WinRAR or 7-Zip |
.7z |
High-ratio Archive |
Efficient compression |
.tar |
Archive (Linux) |
Bundles files before compression |
.gz |
Gzip Compression |
Often used with .tar |
.iso |
Disk Image |
OS images, bootable drives |
| Extension |
Type |
Usage Example |
.exe |
Windows Executable |
Installers, applications |
.msi |
Windows Installer |
Software package format |
.bat |
Batch Script |
Windows automation |
.sh |
Shell Script |
Linux/macOS automation |
.dll |
Dynamic Link Library |
Shared code for Windows apps |
.sys |
System Driver File |
Windows device drivers |
| Extension |
Type |
Usage Example |
.html/.htm |
Web Page |
Website content |
.css |
Stylesheet |
Website design and layout |
.js |
JavaScript |
Web interactivity |
.py |
Python Script |
Scripting, automation, dev |
.json |
Data Format |
Config files, APIs |
.xml |
Markup Data |
Config, structured data |
.conf |
Config File |
System/app configuration |
.ini |
Windows Config |
App settings |
.env |
Environment Var |
App credentials/settings |
| Extension |
Type |
Usage Example |
.pem |
Certificate |
SSL certs, key storage |
.crt |
Certificate |
Public certificate |
.key |
Private Key |
SSL/TLS private key |
.pfx/.p12 |
Encrypted Cert |
Windows cert with key included |
🧠 Tip: Knowing file extensions helps identify file types, choose correct applications, and detect misconfigured or malicious files.