Alphabetically: B
Extension File Description File Type
.b
BASIC Source File
Developer
.b2a
Btoa Encoded File
Encoded
.b5i
BlindWrite 5 Disk Image
Disk Image
.b5t
BlindWrite 5 Disc Track Information File
Disk Image
.b64
Base64 MIME-Encoded File
Compressed
.b6i
BlindWrite 6 Disc Image
Disk Image
.b6t
BlindWrite 6 Track Information File
Disk Image
.ba
Scifer External Header Archive
Compressed
.bac
Backup File
Backup
.backupdb
Time Machine Backup Folder
Backup
.bad
Exchange Badmail File
Text
.bafl
BurnAware File List
Data
.bak
Backup File
Backup
.bak~
AbiWord Auto-Saved Document
Backup
.band
GarageBand Project File
Audio
.bap
Blaze Audio Wave Information File
Audio
.bar
Age of Empires 3 Data File
Game
.bas
BASIC Source Code File
Developer
.bashrc
Bash Non-Interactive Login Shell File
System
.bash_history
Bash History File
System
.bash_profile
Bash Interactive Login Shell File
System
.bat
DOS Batch File
Executable
.bau
OpenOffice.org AutoText File
Settings
.bav
AVG Anti-Virus The Bat! Plugin File
Plugin
.bb
Blitz Source Code File
Developer
.bbc
BBC BASIC Data File
Developer
.bbl
BibTeX Generated Bibliography File
Misc
.bbs
Bulletin Board System Text
Text
.bc
BitComet Partially Downloaded File
Misc
.bc!
BitComet Incomplete File
Misc
.bcc
Calendar Creator File
Data
.bcf
Business Card Designer Pro File
Layout
.bci
Belarc Advisor Report File
Data
.bck
VMX Backup File
Backup
.bckp
Ad-Aware Quarantined File
Backup
.bcm
Microsoft Works Communications Script Backup
Backup
.bcmx
Business Contact Manager Customization
Settings
.bcp
Borland C++ Makefile
Developer
.bct
Adobe Bridge Thumbnail Cache File
Data
.bdb
Microsoft Works Database Backup File
Backup
.bdc
Babylon Dictionary File
Data
.bdd
CARA Sound Radiation Data File
Audio
.bdf
Glyph Bitmap Distribution Format
Font
.bdic
Chrome Dictionary File
Data
.bdl
CoCreate Bundle File
CAD
.bdm
AVHCD Information File
Video
.bdmv
Blu-ray Disc Movie Information File
Video
.bdp
Exchange Diagnostic Message
Text
.bdr
Publisher Borders File
Misc
.bean
Bean Rich Text Document
Text
.bet
BETA Source File
Developer
.bfa
Blowfish Encrypted File
Encoded
.bfc
Windows Briefcase File
Misc
.bff
Backup File Format
Backup
.bfg
Big Fish Games Application File
Game
.bfs
FlatOut Game Data File
Game
.bfx
Bitware Fax Document
Data
.bgi
BgInfo Configuration File
Settings
.bgl
Babylon Glossary File
Data
.bgt
Graphics Accounts Data File
Data
.bgz
Blood Frontier Map File
Game
.bh
BlakHole Archive
Compressed
.bhx
BinHex Encoded File
Encoded
.bib
BibTeX Bibliography Database
Text
.bic
Civilization 3 Scenario
Game
.bif
Boot Information File
Disk Image
.big
Electronic Arts Game Data File
Game
.bik
BINK Video File
Video
.bim
Bytessence InstallMaker Document
Data
.bin
Macbinary Encoded File
Encoded
.bio
BIOS File
System
.bip
Character Studio Biped File
3D Image
.biq
Civilization 3 Scenario
Game
.bix
Civilization 3 Scenario
Game
.biz
Broderbund Business Card File
Layout
.bjo
TablEdit Tablature File
Data
.bk
FrameMaker Book File
Data
.bk1
Autodesk Backup File
Backup
.bkc
Backup4all Backup Catalog
Backup
.bkf
Windows Backup Utility File
Backup
.bkk
BookBuddi eBook File
Data
.bkp
Backup File
Backup
.bks
NTBackup Settings File
Settings
.blb
Blob Data File
Data
.bld
Envisioneer Building Project File
Data
.blend
Blender 3D Data File
3D Image
.blg
Windows Binary Performance Log File
Data
.blk
AutoCAD Block Template File
CAD
.blkrt
Block Artist Image File
Raster Image
.blob
Valve Steam Archive
Settings
.blp
Blizzard Texture File
Game
.bls
Blockland Saved Game File
Game
.blt
AIM Buddy List
Settings
.blu
FileMaker Pro Runtime Extension
Plugin
.blw
Adobe Photoshop Black and White Presets File
Settings
.blz
N-Gage Mobile Video Game File
Game
.bm2
Subspace Bitmap File
Raster Image
.bmc
Bitmap Cache File
Raster Image
.bmd
MU Online Game Data File
Game
.bme
BeatMania 7-Key Song File
Game
.bmf
Binary Material File
Raster Image
.bmk
PowerDVD MovieMark File
Video
.bml
Bean Markup Language File
Web
.bmp
Bitmap Image File
Raster Image
.bms
BeatMania Song File
Game
.bna
Barna Word Processor Document
Text
.bnd
DB2 CLI Bind File
Misc
.bng
The Bingo Maker Card File
Game
.bnk
Test Drive Unlimited Data Package
Game
.bnz
The Bingo Maker Card Template File
Game
.boc
EasyWord Big Document
Text
.bok
TestGen Testbank File
Data
.bom
Mac OS X Bill of Materials File
System
.boo
Booasm Compressed Archive
Compressed
.book
FrameMaker Book File
Layout
.boot
InstallShield Boot File
Settings
.bootskin
Stardock Bootskin File
Misc
.box
E-mail Mailbox
Data
.bp2
AutoCAD Batch Plot File
Misc
.bp3
AutoCAD Batch Plot File
Misc
.bpa
StorageSync Backup Archive
Backup
.bpb
PowerDesigner Business Process Backup File
Backup
.bpg
Borland Project Group
Developer
.bpk
Nero SecurDisc Public Key File
Encoded
.bpl
AutoCAD Batch Plot File
Misc
.bpm
PowerDesigner Business Process Model
Backup
.bps
BPS Virus File
Misc
.br3
Bryce 3 Scene File
3D Image
.br4
Bryce 4 Scene File
3D Image
.br5
Bryce 5 Scene File
3D Image
.br6
Bryce 6 Scene File
3D Image
.br7
Bryce 7 Scene File
3D Image
.brain
PersonalBrain Mind Map File
Data
.brd
EAGLE Circuit Board File
Data
.bri
Bryce Plug-in File
Plugin
.brk
Brooktrout Fax Document
Raster Image
.brm
Bryce Plug-in File
Plugin
.bro
CreataCard Brochure Project
Layout
.browser
ASP.NET Browser Definition File
Web
.brt
Bryce Textures File
Raster Image
.brw
Calyx Point Borrower File
Data
.brx
BREW Application Resource File
Developer
.bs2
BASIC Stamp 2 Code File
Developer
.bs4
Mikogo Session Video Recording
Video
.bsa
Bethesda Softworks Archive
Game
.bsb
BioShock Saved Game File
Game
.bsc
Visual Studio Source Browser Information File
Developer
.bsf
Blu-ray AVC Video File
Video
.bsh
BeanShell Script
Developer
.bsk
Nero SecurDisc Private Key File
Encoded
.bsp
Quake Engine Game Map File
Game
.bst
BibTeX Style Document
Misc
.btapp
uTorrent App
Web
.btf
NationsBank Check Images
Data
.btif
NationsBank Check Image File
Data
.btm
BizTalk Map File
Data
.bto
Bryce Tree File
3D Image
.btoa
Binary-to-ASCII Encoded File
Encoded
.btr
Btrieve Database File
Database
.btsearch
BitTorrent Search Engine File
Settings
.btw
BarTender Label
Layout
.buf
Buffer File
Misc
.bun
Cakewalk Bundle File
Audio
.bundle
Mac OS X Application Plug-in
Plugin
.bup
DVD IFO Backup File
Backup
.bvh
Biovision Hierarchy Animation File
3D Image
.bvp
VodaHost BlueVoda Project File
Data
.bwa
BlindWrite Disk Information File
Disk Image
.bwf
Broadcast Wave File
Audio
.bwi
BlindWrite CD/DVD Disc Image
Disk Image
.bws
BlindWrite Sub Code File
Disk Image
.bwt
BlindWrite 4 Disk Image
Disk Image
.bxx
BS Contact Parameter File
Settings
.byu
Brigham Young University Movie
Video
.bz
Bzip Compressed File
Compressed
.bz2
Bzip2 Compressed File
Compressed
.bzabw
Compressed AbiWord Document
Text
.bzip
Bzip Compressed Archive
Compressed
.bzip2
Bzip2 Compressed Archive
Compressed
.bzw
BZFlag World File
Game