| Extension |
File Type |
File Description |
| .b |
Developer |
BASIC Source File |
| .b5i | Disk | BlindWrite 5 Disk Image |
| .b5t | Disk | BlindWrite 5 Disk Track Information |
| .b64 | Compressed | Base64 MIME-Encoded File |
| .ba | Compressed | Scifer External Header Archive |
| .bac | Backup | Backup File |
| .bad | Text | Exchange Badmail File |
| .bafl | Data | BurnAware File List |
| .bak | Backup | Backup File (Most common) |
| .band | Audio | GarageBand Project File |
| .bap | Audio | Blaze Audio Wave Information File |
| .bas | Developer | BASIC Source Code File |
| .bat | Executable | DOS Batch File |
| .bav | Plugin | AVG Anti-Virus The Bat! Plugin File |
| .bb | Developer | Blitz Source Code File |
| .bbc | Developer | BBC BASIC Data File |
| .bbs | Text | Bulletin Board System Text |
| .bc | Misc | BitComet Partially Downloaded File |
| .bc! | Misc | BitComet Incomplete File |
| .bcf | Page Layout | Business Card Designer Pro File |
| .bci | Data | Belarc Advisor Report File |
| .bck | Backup | VMX Backup File |
| .bckp | Backup | Ad-Aware Quarantined File |
| .bcm | Backup | Microsoft Works Communications Script Backup (Most common) |
| .bcmx | Settings | Business Contact Manager Customization |
| .bcp | Developer | Borland C++ Makefile (Most common) |
| .bdb | Backup | Microsoft Works Database Backup File |
| .bdd | Audio | CARA Sound Radiation Data File |
| .bdf | Font | Glyph Bitmap Distribution Format (Most common) |
| .bdic | Data | Chrome Dictionary File |
| .bdp | Text | Exchange Diagnostic Message |
| .bdr | Misc | Publisher Borders File (Most common) |
| .bean | Text | Bean Rich Text Document |
| .bet | Developer | BETA Source File |
| .bfa | Encoded | Blowfish Encrypted File |
| .bfc | Misc | Windows Briefcase File |
| .bgi | Settings | BgInfo Configuration File |
| .bgl | Data | Babylon Glossary File |
| .bgt | Data | Graphics Accounts Data File |
| .bh | Compressed | BlakHole Archive |
| .bhx | Encoded | BinHex Encoded File |
| .bib | Text | BibTeX Bibliography Database (Most common) |
| .bic | Game | Civilization 3 Scenario |
| .bif | Disk | Boot Information File |
| .big | Game | Electronic Arts Game Data File |
| .bik | Video | BINK Video File (Most common) |
| .bin | Encoded | Macbinary II Encoded File (Most common) |
| .bip | Image | Character Studio Biped File |
| .biq | Game | Civilization 3 Scenario |
| .bix | Game | Civilization 3 Scenario (Most common) |
| .biz | Page Layout | Broderbund Business Card File |
| .bk | Data | FrameMaker Book File |
| .bkc | Backup | Backup4all Backup Catalog |
| .bkf | Backup | Windows Backup Utility File |
| .bkk | Data | BookBuddi eBook File |
| .bkp | Backup | Backup File |
| .bks | Backup | Microsoft Works Spreadsheet Backup File |
| .blb | Data | Blob Data File |
| .blend | Image | Blender 3D Data File |
| .blkrt | Raster Image | Block Artist Image File |
| .blob | Settings | Valve Steam Archive |
| .blp | Game | Blizzard Texture File |
| .bls | Game | Blockland Saved Game File |
| .blt | Settings | AIM Buddy List |
| .blu | Plugin | FileMaker Pro Runtime Extension |
| .blz | Image | Compressed Bitmap Graphic |
| .bmc | Image | Embroidery Image File (Most common) |
| .bmd | Game | GameCube 3D Model File |
| .bme | Game | BeatMania 7-Key Song File |
| .bmf | Raster Image | Binary Material File (Most common) |
| .bmk | System | Help Bookmarks |
| .bml | Web | Bean Markup Language File |
| .bmp | Raster Image | Bitmap Image File |
| .bms | Game | BeatMania Song File |
| .bna | Text | Barna Word Processor Document |
| .bnd | Misc | DB2 CLI Bind File |
| .boc | Text | EasyWord Big Document |
| .bok | Data | TestGen Testbank File (Most common) |
| .boo | Compressed | Booasm Compressed Archive |
| .bootskin | Misc | Stardock Bootskin File |
| .box | Data | E-mail Mailbox (Most common) |
| .bp2 | Misc | AutoCAD Batch Plot File |
| .bp3 | Misc | AutoCAD Batch Plot File |
| .bpa | Backup | StorageSync Backup Archive |
| .bpb | Backup | PowerDesigner Business Process Backup File |
| .bpg | Developer | Borland Project Group |
| .bpm | Backup | PowerDesigner Business Process Model |
| .bps | Backup | Microsoft Works Document Backup |
| .br3 | Image | Bryce 3 Scene File |
| .br4 | Image | Bryce 4 Scene File |
| .br5 | Image | Bryce 3D Scene File |
| .brd | Data | EAGLE Circuit Board File |
| .bro | Page Layout | CreataCard Brochure Project (Most common) |
| .bs2 | Developer | BASIC Stamp 2 Code File |
| .bsa | Game | Bethesda Softworks Archive |
| .bsf | Video | Blu-ray AVC Video File |
| .bsp | Game | Valve Game Map File |
| .bst | Misc | BibTeX Style Document |
| .btf | Data | NationsBank Check Images |
| .btif | Data | NationsBank Check Image File |
| .btm | Data | BizTalk Map File |
| .btw | Page Layout | BarTender Label |
| .buf | Misc | Buffer File |
| .bundle | Plugin | Mac OS X Application Plug-in |
| .bup | Backup | Backup File (Most common) |
| .bvh | Image | Biovision Hierarchy Animation File |
| .bwa | Disk | BlindWrite Disk Information File |
| .bwf | Audio | Broadcast Wave File |
| .bwi | Disk | BlindWrite CD/DVD Disc Image |
| .bws | Disk | BlindWrite Sub Code File |
| .bwt | Disk | BlindWrite 4 Disk Image |
| .byu | Video | Brigham Young University Movie |
| .bz | Compressed | Bzip Compressed File |
| .bz2 | Compressed | Bzip2 Compressed File |
| .bzip | Compressed | Bzip Compressed Archive |
| .bzip2 | Compressed | Bzip2 Compressed Archive |
