X
| Ext. | Description | Used by | |
|---|---|---|---|
| X | Archive | X1.EXE | |
| X | AVS X image file | SDSC Image Tool | |
| X | DirectX 3D object | ||
| X | LEX source code file | ||
| X | XBasic Source code file | Xbasic | |
| X3D | x3d and xdart Formats | ||
| XA | XA audio file | used in SimCity 3000 by Maxis, also by Sony PlayStation | |
| XAR | Xara graphics file | Files created by Xara Photo & Graphic Designer (formerly Xara Xtreme and Xara Studio); early versions used the extension ART | |
| XBE | Xbox Executable | Xbox | |
| XBM | X11 Bitmap graphics file | ||
| XLBL | extensible Business Reporting Language | Business Reporting | |
| XCF | Gimp image file | The Gimp | |
| XCK | Extended crack file (usually text) | ||
| XCL | Xtree for Windows Script file | Xtree for Win | |
| XDF | OS/2 extended disk format image | XDFCOPY.EXE | |
| XDM | Directory Manipulator for 32-bit Protected Mode | Xenotech Research Labs | |
| XE | Xenon - for Associative 3D Modeling | Ashlar-Vellum | |
| XEX | Xbox 360 Executable File | ||
| XFN | Printer font | Xerox 4045 - Ventura Publisher | |
| XFR | Ventura Publisher Bitmap Editor Font file | ||
| XFT | 24 pin printer font | ChiWriter | |
| XI | Fast Tracker 2 instrument file | AWAVE | |
| XI | Fastracker 2.0 Instrument File | Fastracker 2.0 | |
| XIF | Xerox Image Format | Pagis Pro 2.0 and 3.0 | |
| XLA | Add-in macro sheet | Microsoft Excel | |
| XLA | XLib Archive | xlibpas2.zip | |
| XLB | Microsoft Excel Toolbar | Microsoft Excel | |
| XLC | Microsoft Excel Chart | Microsoft Excel | |
| XLD | Microsoft Excel Dialog | Microsoft Excel | |
| XLF | Extensible LADAR Format | LadarSIM | |
| XLK | Microsoft Excel Archive | Microsoft Excel | |
| XLL | Microsoft Excel Dynamic Link Library | Microsoft Excel | |
| XLM | Microsoft Excel Macro File | Microsoft Excel | |
| XLS | Microsoft Excel Spreadsheet | Microsoft Excel | |
| XLSB | Microsoft Excel 2007 Binary Workbook (BIFF12)(Spreadsheets) | Microsoft Excel 2007 (see Microsoft Office 2007 file extensions) | |
| XLSM | Microsoft Excel 2007 Macro-Enabled Workbook (Spreadsheets) | Microsoft Excel 2007 (see Microsoft Office 2007 file extensions) | |
| XLSX | Office Open XML Workbook (Spreadsheets) | Microsoft Excel 2007 (see Microsoft Office 2007 file extensions) | |
| XLT | Microsoft Excel Template | Microsoft Excel | |
| XLT | Translation table | Lotus 1-2-3 - Symphony - Procomm Plus | |
| XLV | Microsoft Excel Module | Microsoft Excel | |
| XLW | Microsoft Excel Workbook | Microsoft Excel | |
| XM | Fast Tracker 2 extended module | AWAVE, Mod4Win, FastTracker, ImpulseTracker | |
| XM | Music format | FastTracker - Cubic Player | |
| XMC | Assisted contact lists file format, based on xml and used in kindergartens and schools | Classmates iPhone app | |
| XMOD | Monarch Model | Monarch Professional | |
| XMI | Compressed eXtended MIdi music | ||
| XML | eXtensible Markup Language file | ||
| XMF | eXtensible Music Format | ||
| XMPZ | XML Miradi Project Zipfile | Miradi | |
| XMV | video | Xbox | |
| XNF | Standard Network File form | ||
| Xnn | Secondary indexes | Borland Paradox | |
| XOF | RenderMorphics | ||
| XP | eXtended Pattern | FastTracker 2.0 | |
| XPL | X-Plane system file | Laminar research | |
| XPM | X11 Pixel Map graphics file | ||
| XPO | Microsoft Dynamics AX Export file | ||
| XPS | Open XML Paper Specification / OpenXPS | open standard document format initially created by Microsoft and similar in concept to Adobe PDF files | |
| XQT | Executable file | Waffle | |
| XQT | Macro sheet | SuperCalc | |
| XRF | Cross-reference file | ||
| XSF | data | Microsoft InfoPath file | |
| XSPF | XML Sharable Playlist Format | ||
| XTB | External translation table | LocoScript | |
| XTP | XTreeGold overlay | XTreeGold | |
| XVF | Xyngo Video File | Xyngo Video Board | |
| XWD | X Window System window dump image graphics file | SDSC Image Tool | |
| XWK | Keyboard mapping | Crosstalk | |
| XWP | Session | Crosstalk | |
| XWP | Text file | Xerox Writer | |
| XX | Encoded file (ASCII) | XXENCODE | |
| XXE | Encoded file (ASCII) | XXENCODE | |
| XY | Text file | XY Write | |
| XY3 | Text file | XYWrite III | |
| XYW | Text file | XyWrite III | |
| XYZ | Molecular coordinates | XMol, RasMol |
Read more about this topic: List Of File Formats (alphabetical)