Important Computer File Extensions | Home Academy Notes
1. Document File Extensions
.doc / .docx → Microsoft Word document
.pdf → Portable Document Format (Adobe PDF)
.txt → Plain text file
.rtf → Rich Text Format
.odt → OpenDocument Text (used in LibreOffice/ OpenOffice)
.wps → Microsoft Works Word Processor file
Exam Highlight: Word files → .doc/.docx, PDFs → .pdf, plain text → .txt
2. Spreadsheet File Extensions
.xls / .xlsx → Microsoft Excel spreadsheet
.csv → Comma Separated Values
.ods → OpenDocument Spreadsheet (LibreOffice/ OpenOffice)
.xlt / .xltx → Excel Template file
Exam Highlight: Excel → .xls/.xlsx, CSV → .csv
3. Presentation File Extensions
.ppt / .pptx → Microsoft PowerPoint presentation
.odp → OpenDocument Presentation
.pot / .potx → PowerPoint Template
.pps / .ppsx → PowerPoint Slide Show
Exam Highlight: PowerPoint → .ppt/.pptx, Template → .pot/.potx
4. Audio/Sound File Extensions
.mp3 → MPEG Audio Layer 3 (most common compressed audio)
.wav → Waveform Audio File
.wma → Windows Media Audio
.aac → Advanced Audio Coding
.flac → Free Lossless Audio Codec
.m4a → Audio-only file from Apple devices
Exam Highlight: MP3 → compressed audio, WAV → uncompressed audio
5. Video File Extensions
.mp4 → MPEG-4 Video File
.avi → Audio Video Interleave (Microsoft)
.mov → QuickTime Video File
.mkv → Matroska Video File
.wmv → Windows Media Video
Exam Highlight: MP4 → widely used, AVI → older format, MKV → high-quality video
6. Image File Extensions
.jpg / .jpeg → Joint Photographic Experts Group (compressed image)
.png → Portable Network Graphics (supports transparency)
.gif → Graphics Interchange Format (animated images)
.bmp → Bitmap Image File
.tiff / .tif → Tagged Image File Format
Exam Highlight: JPEG → compressed, PNG → transparency, GIF → animation
7. Compressed/Archive File Extensions
.zip → Compressed archive
.rar → WinRAR archive
.7z → 7-Zip archive
.tar / .gz → Linux archive formats
Exam Highlight: ZIP → widely used, RAR → requires WinRAR
.html / .htm → HyperText Markup Language
.css → Cascading Style Sheets
.js → JavaScript file
.php → PHP script
.xml → Extensible Markup Language
Exam Highlight: HTML → web pages, CSS → styling, JS → scripting
9. Database File Extensions
.mdb / .accdb → Microsoft Access database
.sql → SQL database script file
.db / .dbf → Generic database file
Exam Highlight: Access → .mdb/.accdb, SQL script → .sql
10. Miscellaneous / System File Extensions
.exe → Executable file (Windows program)
.bat → Batch file
.dll → Dynamic Link Library
.iso → Disk image file
.apk → Android Package file
Exam Highlight: .exe → runs programs, .dll → library, .iso → disk image