File Extension Index

A file extension is the suffix after a filename (for example, .pdf or .heic) that helps your device choose the right app. This index is the crawl hub for all extension and how-to pages. Categories are alphabetized for discoverability and each list is popularity-sorted.

Total indexed extensions: 623

Categories

• Archives (58)
• Audio (73)
• CAD (4)
• Certificates (3)
• Code (16)
• Data (142)
• Documents (127)
• eBooks (2)
• Images (110)
• Subtitles (3)
• System (15)
• Video (64)
• Web (6)

Compressed and packaged files used for transfer, backup, and software distribution.

Most common file types in this category (top 5):

• .zip

  ZIP Archive

  ZIP archives bundle multiple files/folders into a compressed container for easier sharing.

  Open on Windows Open on Mac
• .rar

  RAR Archive

  RAR is a compressed archive format known for strong compression and multi-part archives.

  Open on Windows Open on Mac
• .7z

  7-Zip Archive

  7Z files are compressed archives that offer high compression rates and are commonly opened with 7-Zip.

  Open on Windows Open on Mac
• .gz

  Gzip Compressed File

  GZ files are gzip-compressed streams commonly used with TAR archives and log compression.

  Open on Windows Open on Mac
• .tar

  Tape Archive

  TAR archives bundle files without compression and are common in Unix/Linux distributions.

  Open on Windows Open on Mac

Common music and sound formats for streaming, editing, and distribution.

Most common file types in this category (top 5):

• .mp3

  MPEG Audio Layer III

  MP3 is a widely supported lossy audio format for music, podcasts, and voice recordings.

  Open on Windows Open on Mac
• .wav

  Waveform Audio File

  WAV files typically store uncompressed PCM audio and are common in recording/editing workflows.

  Open on Windows Open on Mac
• .aa3

  AA3 Audio File

  .AA3 files are used for music playback, podcast distribution, recording, and audio editing. Open with audio players, DAWs, or converters that support this format. This guide covers opening methods, troubleshooting, and security best practices. Common MIME type: audio/ATRAC3.

  Open on Windows Open on Mac
• .aac

  AAC Audio File

  .AAC files are used for music playback, podcast distribution, recording, and audio editing. Open with audio players, DAWs, or converters that support this format. This guide covers opening methods, troubleshooting, and security best practices. Common MIME type: audio/aac.

  Open on Windows Open on Mac
• .au

  AU Audio File

  .AU files are used for music playback, podcast distribution, recording, and audio editing. Open with audio players, DAWs, or converters that support this format. This guide covers opening methods, troubleshooting, and security best practices. Common MIME type: audio/basic.

  Open on Windows Open on Mac

Computer-aided design and technical drawing formats used in engineering, architecture, and manufacturing.

Most common file types in this category (top 5):

• .cdr

  CDR Image File

  .CDR files are used for technical drawings, engineering design, and manufacturing workflows. Use CAD viewers/editors that support this design format. This guide covers opening methods, troubleshooting, and security best practices. Common MIME type: image/x-coreldraw.

  Open on Windows Open on Mac
• .cgm

  CGM Image File

  .CGM files are used for technical drawings, engineering design, and manufacturing workflows. Use CAD viewers/editors that support this design format. This guide covers opening methods, troubleshooting, and security best practices. Common MIME type: image/cgm.

  Open on Windows Open on Mac
• .dwg

  DWG Image File

  .DWG files are used for technical drawings, engineering design, and manufacturing workflows. Use CAD viewers/editors that support this design format. This guide covers opening methods, troubleshooting, and security best practices. Common MIME type: image/vnd.dwg.

  Open on Windows Open on Mac
• .dxf

  DXF Image File

  .DXF files are used for technical drawings, engineering design, and manufacturing workflows. Use CAD viewers/editors that support this design format. This guide covers opening methods, troubleshooting, and security best practices. Common MIME type: image/vnd.dxf.

  Open on Windows Open on Mac

Digital certificate and cryptographic trust files used for identity, signing, and secure connections.

Most common file types in this category (top 5):

• .cer

  CER Data File

  .CER files are used for identity verification, encryption, signatures, and TLS trust chains. Open/import them with certificate managers or security tooling. This guide covers opening methods, troubleshooting, and security best practices. Common MIME type: application/pkix-cert.

  Open on Windows Open on Mac
• .crl

  CRL Data File

  .CRL files are used for identity verification, encryption, signatures, and TLS trust chains. Open/import them with certificate managers or security tooling. This guide covers opening methods, troubleshooting, and security best practices. Common MIME type: application/pkix-crl.

  Open on Windows Open on Mac
• .crt

  CRT Data File

  .CRT files are used for identity verification, encryption, signatures, and TLS trust chains. Open/import them with certificate managers or security tooling. This guide covers opening methods, troubleshooting, and security best practices. Common MIME type: application/x-x509-ca-cert.

  Open on Windows Open on Mac

Source code and script files used for software development and automation workflows.

Most common file types in this category (top 5):

• .cc

  CC Document File

  .CC files are used for software development, scripts, and automation tasks. Open with source-code editors or IDEs that support syntax highlighting and tooling. This guide covers opening methods, troubleshooting, and security best practices. Common MIME type: text/x-c++src.

  Open on Windows Open on Mac
• .hh

  HH Document File

  .HH files are used for software development, scripts, and automation tasks. Open with source-code editors or IDEs that support syntax highlighting and tooling. This guide covers opening methods, troubleshooting, and security best practices. Common MIME type: text/x-c++hdr.

  Open on Windows Open on Mac
• .js

  JS Document File

  .JS files are used for software development, scripts, and automation tasks. Open with source-code editors or IDEs that support syntax highlighting and tooling. This guide covers opening methods, troubleshooting, and security best practices. Common MIME type: text/javascript.

  Open on Windows Open on Mac
• .pl

  PL Document File

  .PL files are used for software development, scripts, and automation tasks. Open with source-code editors or IDEs that support syntax highlighting and tooling. This guide covers opening methods, troubleshooting, and security best practices. Common MIME type: text/x-perl.

  Open on Windows Open on Mac
• .py

  PY Document File

  .PY files are used for software development, scripts, and automation tasks. Open with source-code editors or IDEs that support syntax highlighting and tooling. This guide covers opening methods, troubleshooting, and security best practices. Common MIME type: text/x-python.

  Open on Windows Open on Mac

Structured machine-readable files used by apps, APIs, and automation workflows.

Most common file types in this category (top 5):

• .json

  JavaScript Object Notation

  JSON is a lightweight text format used for APIs, configuration files, and data exchange.

  Open on Windows Open on Mac
• .pkpass

  Apple Wallet Pass

  PKPASS files contain digital tickets, boarding passes, coupons, and loyalty cards for wallet apps.

  Open on Windows Open on Mac
• .ac

  AC Data File

  .AC files are used for structured application data, imports/exports, and machine-readable workflows. Open with the originating app, text editors, or specialized data tools. This guide covers opening methods, troubleshooting, and security best practices. Common MIME type: application/pkix-attr-cert.

  Open on Windows Open on Mac
• .cl

  CL Data File

  .CL files are used for structured application data, imports/exports, and machine-readable workflows. Open with the originating app, text editors, or specialized data tools. This guide covers opening methods, troubleshooting, and security best practices. Common MIME type: application/simple-filter+xml.

  Open on Windows Open on Mac
• .cu

  CU Data File

  .CU files are used for structured application data, imports/exports, and machine-readable workflows. Open with the originating app, text editors, or specialized data tools. This guide covers opening methods, troubleshooting, and security best practices. Common MIME type: application/cu-seeme.

  Open on Windows Open on Mac

Text and office document formats used for reports, slides, and spreadsheets.

Most common file types in this category (top 5):

• .pdf

  Portable Document Format

  PDF files preserve document layout across devices and are widely used for forms, reports, and ebooks.

  Open on Windows Open on Mac
• .docx

  Microsoft Word Open XML Document

  DOCX files are editable word-processing documents used by Microsoft Word and compatible office suites.

  Open on Windows Open on Mac
• .xlsx

  Microsoft Excel Open XML Spreadsheet

  XLSX files store spreadsheet data, formulas, charts, and pivot tables.

  Open on Windows Open on Mac
• .pptx

  Microsoft PowerPoint Open XML Presentation

  PPTX files store slide decks with text, images, video, transitions, and speaker notes.

  Open on Windows Open on Mac
• .txt

  Plain Text File

  TXT files contain unformatted plain text and are readable on virtually any operating system.

  Open on Windows Open on Mac

Digital book formats used by e-readers, publishing tools, and reading apps.

Most common file types in this category (top 5):

• .azw3

  AZW3 Document File

  .AZW3 files are used for digital publishing, reading apps, and e-reader distribution. Use e-reader apps or document tools that support this ebook format. This guide covers opening methods, troubleshooting, and security best practices. Common MIME type: application/vnd.amazon.mobi8-ebook.

  Open on Windows Open on Mac
• .epub

  EPUB Document File

  .EPUB files are used for digital publishing, reading apps, and e-reader distribution. Use e-reader apps or document tools that support this ebook format. This guide covers opening methods, troubleshooting, and security best practices. Common MIME type: application/epub+zip.

  Open on Windows Open on Mac

Raster and vector image formats used for photos, graphics, and design.

Most common file types in this category (top 5):

• .jpg

  JPEG Image

  JPG/JPEG is a compressed raster image format widely used for photos and web graphics.

  Open on Windows Open on Mac
• .png

  Portable Network Graphics

  PNG is a lossless image format that supports transparency and crisp text rendering.

  Open on Windows Open on Mac
• .gif

  Graphics Interchange Format

  GIF supports simple animations and indexed-color still images.

  Open on Windows Open on Mac
• .svg

  Scalable Vector Graphics

  SVG files are XML-based vector graphics that scale without losing quality.

  Open on Windows Open on Mac
• .heic

  High Efficiency Image Container

  HEIC stores high-quality photos at smaller sizes, commonly produced by modern smartphones.

  Open on Windows Open on Mac

Caption and subtitle text formats that accompany video and multimedia playback.

Most common file types in this category (top 5):

• .ass

  ASS Audio File

  .ASS files are used for captions and subtitle tracks for media playback. Open with media players, subtitle editors, or video authoring tools. This guide covers opening methods, troubleshooting, and security best practices. Common MIME type: audio/aac.

  Open on Windows Open on Mac
• .srt

  SRT Document File

  .SRT files are used for captions and subtitle tracks for media playback. Open with media players, subtitle editors, or video authoring tools. This guide covers opening methods, troubleshooting, and security best practices. Common MIME type: text/plain.

  Open on Windows Open on Mac
• .vtt

  VTT Document File

  .VTT files are used for captions and subtitle tracks for media playback. Open with media players, subtitle editors, or video authoring tools. This guide covers opening methods, troubleshooting, and security best practices. Common MIME type: text/vtt.

  Open on Windows Open on Mac

Installer, executable, and system-level package formats used by operating systems and applications.

Most common file types in this category (top 5):

• .apk

  APK Archive File

  .APK files are used for installation packages, updates, and system-level deployment workflows. Open only with trusted system utilities or package managers. This guide covers opening methods, troubleshooting, and security best practices. Common MIME type: application/vnd.android.package-archive.

  Open on Windows Open on Mac
• .cab

  CAB Archive File

  .CAB files are used for installation packages, updates, and system-level deployment workflows. Open only with trusted system utilities or package managers. This guide covers opening methods, troubleshooting, and security best practices. Common MIME type: application/vnd.ms-cab-compressed.

  Open on Windows Open on Mac
• .deb

  DEB Archive File

  .DEB files are used for installation packages, updates, and system-level deployment workflows. Open only with trusted system utilities or package managers. This guide covers opening methods, troubleshooting, and security best practices. Common MIME type: application/vnd.debian.binary-package.

  Open on Windows Open on Mac
• .dmg

  DMG Archive File

  .DMG files are used for installation packages, updates, and system-level deployment workflows. Open only with trusted system utilities or package managers. This guide covers opening methods, troubleshooting, and security best practices. Common MIME type: application/x-apple-diskimage.

  Open on Windows Open on Mac
• .iso

  ISO Archive File

  .ISO files are used for installation packages, updates, and system-level deployment workflows. Open only with trusted system utilities or package managers. This guide covers opening methods, troubleshooting, and security best practices. Common MIME type: application/x-iso9660-image.

  Open on Windows Open on Mac

Video container formats for playback, editing, and sharing.

Most common file types in this category (top 5):

• .mp4

  MPEG-4 Part 14 Video

  MP4 is a popular multimedia container for video, audio, subtitles, and metadata.

  Open on Windows Open on Mac
• .mkv

  Matroska Video

  MKV is a flexible multimedia container often used for high-quality video and multiple subtitle/audio tracks.

  Open on Windows Open on Mac
• .dv

  DV Video File

  .DV files are used for playback, editing, streaming, and distribution of video content. Use media players or editors with the required codecs and container support. This guide covers opening methods, troubleshooting, and security best practices. Common MIME type: video/dv.

  Open on Windows Open on Mac
• .gl

  GL Video File

  .GL files are used for playback, editing, streaming, and distribution of video content. Use media players or editors with the required codecs and container support. This guide covers opening methods, troubleshooting, and security best practices. Common MIME type: video/gl.

  Open on Windows Open on Mac
• .qt

  QT Video File

  .QT files are used for playback, editing, streaming, and distribution of video content. Use media players or editors with the required codecs and container support. This guide covers opening methods, troubleshooting, and security best practices. Common MIME type: video/quicktime.

  Open on Windows Open on Mac

Web markup, stylesheet, and related assets used by browsers and web platforms.

Most common file types in this category (top 5):

• .css

  CSS Document File

  .CSS files are used for web pages, browser rendering, and front-end assets. Open with web browsers, code editors, or build tools for web development. This guide covers opening methods, troubleshooting, and security best practices. Common MIME type: text/css.

  Open on Windows Open on Mac
• .htm

  HTM Document File

  .HTM files are used for web pages, browser rendering, and front-end assets. Open with web browsers, code editors, or build tools for web development. This guide covers opening methods, troubleshooting, and security best practices. Common MIME type: text/html.

  Open on Windows Open on Mac
• .svgz

  SVGZ Image File

  .SVGZ files are used for web pages, browser rendering, and front-end assets. Open with web browsers, code editors, or build tools for web development. This guide covers opening methods, troubleshooting, and security best practices. Common MIME type: image/svg+xml.

  Open on Windows Open on Mac
• .xml

  XML Document File

  .XML files are used for web pages, browser rendering, and front-end assets. Open with web browsers, code editors, or build tools for web development. This guide covers opening methods, troubleshooting, and security best practices. Common MIME type: application/xml.

  Open on Windows Open on Mac
• .xul

  XUL Document File

  .XUL files are used for web pages, browser rendering, and front-end assets. Open with web browsers, code editors, or build tools for web development. This guide covers opening methods, troubleshooting, and security best practices. Common MIME type: text/xul.

  Open on Windows Open on Mac