| Extension |
File Description |
|
Popularity |
| .$er | GroupWise Database | | Average |
| .123 | Lotus 1-2-3 Spreadsheet | | Very Common |
| .123 | PCB123 Circuit Board Design | | Average |
| .1pe | TurboTax Form File | | Average |
| .1ph | TurboTax File | | Average |
| .3dt | 3D Topicscape File | | Average |
| .4dl | 4th Dimension Database Log File | | Uncommon |
| .4dv | 4D View Ultrasound File | | Average |
| .a3l | Authorware 3 Library | | Average |
| .a3m | Authorware 3 Macintosh File | | Average |
| .a3w | Authorware 3 Windows File | | Average |
| .a4l | Authorware 4 Library | | Average |
| .a4m | Authorware 4 Macintosh File | | Average |
| .a4w | Authorware 4 Windows File | | Average |
| .a5l | Authorware 5 Library | | Average |
| .a5w | Authorware 5 Windows File | | Average |
| .a65 | Authorware 6.5 File | | Average |
| .ab | DNA Sequence File | | Average |
| .ab1 | DNA Electropherogram File | | Average |
| .ab3 | PhotoImpact 3 Album File | | Average |
| .abcd | AudioVisual Book Data File | | Average |
| .abi | DNA Chromatogram File | | Average |
| .abp | AVS Barcode Profile | | Average |
| .aca | Agent Character Animation File | | Uncommon |
| .acc | Graphics Accounts Data File | | Average |
| .accdb | Access 2007 Database File | | Very Common |
| .acf | Agent Character Data File | | Uncommon |
| .acg | Agent Preview File | | Uncommon |
| .ade | Access Project Extension | | Average |
| .adp | Access Project | | Average |
| .adt | ACT! Document Template | | Average |
| .adx | Approach Index File | | Average |
| .aft | Ancestry.com Family Tree Database | | Average |
| .aifb | AIF Builder Project File | | Average |
| .alc | Dynamics AX Label Description File | | Average |
| .ald | Dynamics AX Application Label Data File | | Average |
| .ali | Dynamics AX Label Index File | | Average |
| .amb | AIMMS Model File | | Average |
| .an1 | Street Atlas USA Draw File | | Uncommon |
| .anme | Anime Studio Project | | Common |
| .apr | ArcView Project File | | Average |
| .ask | askSam Database | | Average |
| .asm | Solid Edge Assembly Document | | Average |
| .ast | ClarisWorks Assistant File | | Uncommon |
| .awg | Activeworlds Object Group File | | Average |
| .azw | Amazon Kindle eBook File | | Average |
| .bafl | BurnAware File List | | Uncommon |
| .bci | Belarc Advisor Report File | | Average |
| .bcm | Business Contact Manager File | | Average |
| .bdf | Binary Data File | | Uncommon |
| .bdic | Chrome Dictionary File | | Average |
| .bgl | Babylon Glossary File | | Average |
| .bgt | Graphics Accounts Data File | | Average |
| .bin | Generic Binary File | | Average |
| .bk | FrameMaker Book File | | Average |
| .bkk | BookBuddi eBook File | | Average |
| .blb | Blob Data File | | Average |
| .bok | TestGen Testbank File | | Average |
| .box | E-mail Mailbox | | Average |
| .brd | EAGLE Circuit Board File | | Average |
| .btf | NationsBank Check Images | | Uncommon |
| .btif | NationsBank Check Image File | | Rare |
| .btm | BizTalk Map File | | Average |
| .cap | Packet Capture File | | Average |
| .cat | Advanced Disk Catalog Database | | Average |
| .cbg | CyberGauge Data File | | Average |
| .cch | Corel Chart File | | Average |
| .ccr | ASTM Continuity of Care Record | | Average |
| .cct | Director Protected Cast Resource | | Uncommon |
| .cdf | Common Data Format | | Uncommon |
| .cdf | Content Definition File | | Common |
| .cdr | Crash Data Retrieval Data File | | Uncommon |
| .cdx | Compound Index File | | Average |
| .celtx | Celtx Project File | | Average |
| .chg | Quicken Online Data File | | Average |
| .chk | InterCheck Checksum Database | | Uncommon |
| .chn | Ethnograph Data | | Average |
| .ckd | Kubotek Design Container | | Uncommon |
| .ckt | CircuitMaker File | | Average |
| .clix | CLIX Command File | | Uncommon |
| .clp | Windows Clipboard File | | Average |
| .cna | Catena Project File | | Average |
| .crd | Windows Cardfile | | Average |
| .csa | PNA Code Calset File | | Average |
| .csv | Comma Separated Values File | | Very Common |
| .ctf | WhereIsIt Catalog | | Average |
| .ctt | Messenger Contact List | | Average |
| .cvn | CineVision Encoding Session | | Average |
| .cwk | ClarisWorks Document | | Average |
| .cws | Claris Works Template | | Average |
| .cwz | Circuit Wizard File | | Uncommon |
| .cxt | Director Protected Cast File | | Rare |
| .cyo | Clustify Output File | | Average |
| .cys | Clustify Summary File | | Average |
| .daf | Digital Anchor File | | Uncommon |
| .dal | DVD-lab Project File | | Average |
| .dam | DeltaMaster Analysis Model | | Average |
| .das | DeltaMaster Analysis Session | | Average |
| .dat | Data File | | Very Common |
| .db | Database File | | Very Common |
| .db2 | dBASE II Database | | Average |
| .dbc | FoxPro Database | | Average |
| .dbd | DemoShield Project | | Average |
| .dbf | Database File | | Average |
| .dbf | FoxPro Table | | Average |
| .dbx | Visual FoxPro Table | | Average |
| .dcf | Document Computation Format | | Common |
| .dcl | DumpSec Report File | | Average |
| .dcm | DiskCatalogMaker Catalog File | | Average |
| .dcmd | DiskCatalogMaker Thumbnail-Enabled Catalog | | Average |
| .ddc | DivX Descriptor File | | Average |
| .ddcx | DivX Descriptor 2 File | | Average |
| .dem | Digital Elevation Model | | Average |
| .des | QuickBooks Forms Template | | Average |
| .dex | DEXIS Digital X-ray File | | Average |
| .dex | Excel Spreadsheet | | Average |
| .dfm | Midas ViewPoint Display Form | | Average |
| .dfproj | DVD Flick Project | | Average |
| .dft | Solid Edge Draft Document | | Average |
| .dgb | FlashCAD Drawing Database | | Average |
| .dif | Data Interchange Format | | Common |
| .dii | Summation Batch Load File | | Average |
| .dlg | Digital Line Graph | | Average |
| .dll | Dynamic Link Library | | Very Common |
| .dm2 | Toad Data Modeler 2 File | | Average |
| .dmo | Derive Demo | | Average |
| .dmo | Movienizer Database File | | Average |
| .dockzip | ObjectDock File | | Average |
| .dp1 | DataPower Database File | | Average |
| .dpn | Depiction Data File | | Average |
| .drl | Gerber Drill Rack File | | Average |
| .dsb | Orchida Embroidery File | | Average |
| .dsd | Diet Studio Data File | | Uncommon |
| .dsk | Simple IDs Database | | Average |
| .dsy | Directory Synchronizer Project File | | Average |
| .dsz | Orchida (OES) Embroidery File | | Average |
| .dtr | DATroniC Data Recording | | Average |
| .dvdproj | iDVD Project File | | Average |
| .dwi | Dance With Intensity Song File | | Average |
| .e00 | ArcInfo Coverage Export File | | Uncommon |
| .eap | Enterprise Architect Project | | Average |
| .ebuild | Portage eBuild Script | | Average |
| .eco | ECCO Database File | | Average |
| .ecx | ECCO Corrupted Database File | | Average |
| .edb | Exchange Information Store Database | | Average |
| .edf | Estimator Data File | | Average |
| .eep | EEPROM Data File | | Rare |
| .emb | Embroidery Design File | | Average |
| .emb | Everest Embedded Bank File | | Average |
| .emd | ChessBase Tablebase | | Average |
| .emlxpart | Mail Message Attachment | | Average |
| .enc | Electronic Navigation Chart File | | Uncommon |
| .epp | TalaPhoto Project | | Average |
| .epp | Efficient PPC Project File | | Average |
| .epub | Open eBook File | | Average |
| .epw | EnergyPlus Weather Data File | | Common |
| .er1 | ERWin Entity Relationship Diagram | | Average |
| .esp | ACD/Labs Dataset | | Average |
| .ess | EasySpreadsheet Spreadsheet | | Average |
| .est | Streets & Trips Map File | | Average |
| .ev | Echoview File | | Average |
| .evy | Envoy File | | Average |
| .exp | Export File | | Common |
| .exp | Aurora Expert Trace File | | Average |
| .exx | IBM Linkway MsgPut File | | Average |
| .fa | FASTA Formatted Sequence File | | Average |
| .fasta | FASTA Sequence File | | Average |
| .fcd | First Choice Database | | Average |
| .fcs | First Choice Spreadsheet | | Average |
| .fdb | Portfolio Catalog | | Common |
| .fdb | Art Explosion Catalog | | Average |
| .fdb | Microsoft Dynamics NAV Database File | | Average |
| .ffd | Flat File Description | | Average |
| .ffwp | FormsForWeb Packet | | Average |
| .fhc | FHC Data File | | Average |
| .fid | File Expander Engine Descriptions Database | | Uncommon |
| .fil | Files List Object File | | Average |
| .flame | Fractal Flame File | | Average |
| .fll | FoxPro Dynamic-Link Library | | Average |
| .flo | iGrafx FlowCharter File | | Average |
| .flo | RFFlow Flowchart File | | Average |
| .flp | Activprimary Flipchart File | | Average |
| .flt | Flight Simulator Saved Flight | | Average |
| .fm | FileMaker Spreadsheet | | Average |
| .fm5 | FileMaker 5 Database | | Average |
| .fmp | FileMaker Pro Database | | Average |
| .fo | XSL-FO Form | | Average |
| .fob | Dynamics NAV Object Container File | | Average |
| .fop | InfoZoom Protected Data File | | Average |
| .fox | InfoZoom Data File | | Average |
| .fp | FileMaker Pro Spreadsheet | | Average |
| .fp3 | FileMaker Pro 3 Database | | Average |
| .fp4 | FileMaker Pro 4 Database | | Average |
| .fp5 | FileMaker Pro 5 Database | | Average |
| .fp7 | FileMaker Pro 7+ Database | | Average |
| .frl | Electronic Form Loader | | Average |
| .frm | ADL Form | | Average |
| .frm | MySQL Database Format File | | Average |
| .fro | dBASE IV Compiled Report | | Average |
| .frx | FoxPro Report | | Average |
| .fsb | FMOD Sample Bank File | | Average |
| .fsc | Practical Scriptwriter File | | Average |
| .ftm | Family Tree Maker for DOS File | | Average |
| .ftw | Family Tree Maker File | | Average |
| .gan | GanttProject Project File | | Average |
| .gbr | Gerber File | | Average |
| .gc | GraphClick File | | Average |
| .gcx | Grapher Graph File | | Average |
| .gdb | InterBase Database File | | Uncommon |
| .ged | GEDCOM Genealogy Data File | | Average |
| .gedcom | GEDCOM Genealogy File | | Average |
| .gen | ArcView ARC/INFO UnGenerate file | | Uncommon |
| .ggb | GeoGebra Document | | Average |
| .gml | Geography Markup Language File | | Average |
| .gms | Gesture and Motion Signal File | | Average |
| .gnp | GNPeak Output File | | Rare |
| .gp3 | Guitar Pro 3 File | | Average |
| .gpx | GPS Exchange File | | Common |
| .gra | Microsoft Graph File | | Average |
| .grade | GradeStat Document | | Average |
| .grf | Generic Graph File | | Average |
| .grf | DPlot Graph File | | Average |
| .grib | Gridded Binary File | | Average |
| .grk | Gradekeeper Class Gradebook File | | Average |
| .grr | Gradekeeper Class Roster File | | Average |
| .gs | GemStone Document | | Average |
| .gst | MapInfo Geoset File | | Average |
| .gtp | Guitar Pro File | | Average |
| .gwk | GraphiCode PCB Job File | | Average |
| .gxl | Graph Exchange Language File | | Average |
| .hda | HotDocs Auto-Assemble File | | Average |
| .hdf | Hierarchical Data Format File | | Common |
| .hdi | HotDocs Auto-Install File | | Average |
| .hdl | HotDocs Library | | Average |
| .hif | Quicken Online File | | Average |
| .hl | HeuristicLab Storage File | | Average |
| .hml | HostMonitor TestList File | | Average |
| .hs2 | HyperRESEARCH 2 Study File | | Average |
| .hsk | Huskey Truss & Building Supply Import File | | Rare |
| .hst | History File | | Average |
| .i5z | IUCLID 5 Import/Export File | | Average |
| .ib | InterBase Database | | Average |
| .ics | iCalendar File | | Average |
| .idx | HMI Historical Log Index File | | Average |
| .idx | Navigation POI File | | Average |
| .igc | Anime List Builder Input File | | Average |
| .ihx | IN-HEH Timeline Database | | Average |
| .iif | Intuit Interchange Format File | | Average |
| .ink | Mimio Ink Data File | | Uncommon |
| .inp | ABAQUS Input File | | Average |
| .ins | Inspiration File | | Common |
| .ip | IconPackager Theme File | | Average |
| .irock | intelliRock Sensor Data File | | Average |
| .irr | Brewer Lamp File | | Uncommon |
| .irx | Brewer Irradiation File | | Rare |
| .isf | Inspiration Flowchart Document | | Average |
| .itdb | iTunes Database File | | Average |
| .itl | iTunes Library File | | Average |
| .itm | iThink Model File | | Average |
| .itn | TomTom Navigator Itinerary File | | Average |
| .itw | InTouch With Database File | | Average |
| .itx | ITX Form Template | | Average |
| .ivt | Beyond 20/20 Table | | Average |
| .jef | Janome Embroidery Format | | Average |
| .jnt | Windows Journal File | | Common |
| .jph | JProbe Memory Snapshot | | Average |
| .jude | JUDE Project File | | Average |
| .kdb | Keypass Database File | | Average |
| .kid | Kidspiration Document | | Average |
| .kmz | Google Earth Placemark File | | Common |
| .kpf | Komodo Project File | | Average |
| .kpp | Kid Pix Presentation | | Average |
| .kpr | KPresenter Presentation | | Average |
| .kpx | Kid Pix Picture | | Average |
| .kpz | Komodo Template File | | Average |
| .l | Game of Life File | | Average |
| .l6t | Line 6 Tone File | | Average |
| .lbx | FoxPro Label File | | Uncommon |
| .lcd | ABBYY Language File | | Average |
| .lcf | ArchiCAD Library Container File | | Average |
| .lcm | Lipikar Custom Map File | | Average |
| .ldif | LDAP Data Interchange Format File | | Average |
| .lgc | SimpleK Database File | | Average |
| .lgf | PMSCAN Log File | | Uncommon |
| .lgh | HMI Historical Log File | | Average |
| .lgi | Multimedia Logic File | | Average |
| .lgl | Large Graph Layout Edge File | | Rare |
| .lib | Generic Data Library | | Common |
| .lif | TurboTax Information Archive | | Average |
| .lix | Logos Library System File | | Average |
| .lix | ExtendSim Simulation Software Library | | Average |
| .llb | LabVIEW Library File | | Average |
| .lms | LenMus Score File | | Average |
| .lnt | LiveNote Case File | | Uncommon |
| .loc | GPS Location File | | Average |
| .lp7 | LP7 Digitally Signed File | | Average |
| .lsf | Logos Library System File | | Average |
| .lsl | LightScribe Label | | Average |
| .lsp | LANsurveyor Poll List | | Average |
| .lsr | LANsurveyor Report | | Average |
| .lst | LightScribe Label Template | | Uncommon |
| .lsu | LANsurveyor Map | | Average |
| .lw4 | Lightwright File | | Average |
| .m | Mathematica Input File | | Common |
| .mag | Magic Circuit Layout | | Average |
| .mai | Microsoft Mail File | | Average |
| .map | Weather Defender Map | | Average |
| .mat | MATLAB Variables Binary File | | Average |
| .mbg | Mailbag Assistant Mailbox File | | Average |
| .mbg | Microsoft Mailbag | | Average |
| .mbl | Logger Pro Data File | | Average |
| .mbp | Mobipocket Notes File | | Average |
| .mbx | Outlook Express Mailbox | | Average |
| .mc1 | MedCalc Data File | | Average |
| .mc9 | Mastercam 9 Geometry File | | Average |
| .mcd | Mathcad Document | | Average |
| .md | Moneydance Financial Data File | | Average |
| .mdb | Microsoft Access Database | | Very Common |
| .mdc | Multi Dimension Cube File | | Average |
| .mdf | Measurement Data Format File | | Average |
| .mdf | SQL Server Database File | | Average |
| .mdl | Simulink Model File | | Average |
| .mdl | Rational Rose Model File | | Average |
| .mdn | Blank Access Database Template | | Average |
| .mdt | Access Database Template | | Average |
| .mdx | Multiple Index File | | Average |
| .mdx | Rational XDE Model File | | Average |
| .mdz | Access Wizard Template | | Average |
| .mem | Mnemosyne Card Collection | | Uncommon |
| .mex | Macro Express File | | Average |
| .mfo | Perl ModInfo Descriptor File | | Average |
| .mfp | Macromedia FlashPaper Document | | Average |
| .mgc | MGCSoft Equation Illustrator File | | Average |
| .mls | Milestones Simplicity File | | Average |
| .mm | FreeMind Mind Map | | Average |
| .mmap | MindManager Map File | | Average |
| .mmc | Microsoft Media Catalog | | Average |
| .mmf | Microsoft Message File | | Uncommon |
| .mmp | MindManager Mind Map | | Average |
| .mmp | Master Album Maker Project | | Average |
| .mnc | My Notes Center Notebook | | Average |
| .mng | Yamaha PSR Disk Manager File | | Rare |
| .mnk | My Notes Keeper Notebook | | Average |
| .mno | Macromedia Design Note | | Average |
| .mny | Microsoft Money File | | Average |
| .mobi | Mobipocket eBook | | Average |
| .moho | Anime Studio Animation Project | | Average |
| .mosaic | MacOSaiX Mosaic File | | Average |
| .mox | ExtendSim Simulation Software Model | | Average |
| .mpp | Microsoft Project File | | Common |
| .mpt | Microsoft Project Template | | Average |
| .mpx | Microsoft Project Exchange File | | Average |
| .mq4 | MetaTrader Custom Indicator | | Average |
| .ms10 | Multisim Circuit Design | | Uncommon |
| .mth | Derive Math File | | Average |
| .mud | Textease Multi User Database | | Average |
| .mw | Maple Worksheet | | Common |
| .mws | Maple Classic Worksheet | | Average |
| .mxd | ArcGIS Map Document | | Average |
| .myd | MySQL Database Data File | | Average |
| .myi | MySQL MyISAM Index File | | Average |
| .nb | Mathematica Notebook | | Average |
| .ndf | SQL Server Secondary Database File | | Average |
| .ndk | Lotus Notes Design Elements File | | Average |
| .ndx | dBASE Index File | | Common |
| .net | netViz Project File | | Average |
| .neta | Netica Binary File | | Average |
| .nitf | National Imagery Transmission Format File | | Average |
| .nmind | NovaMind Mind Map File | | Average |
| .not | Notation File | | Common |
| .notebook | SMART Notebook File | | Average |
| .np | Portfolio NetPublish File | | Average |
| .npl | Nokia Playlist File | | Average |
| .npt | Portfolio NetPublish Template | | Average |
| .ns2 | Lotus Notes 2 Database | | Average |
| .ns3 | Lotus Notes 3 Database | | Average |
| .ns4 | Lotus Notes 4 Database | | Average |
| .nsf | Lotus Notes Database | | Average |
| .nsf | Lotus Domino Database | | Average |
| .ntx | Clipper Index File | | Uncommon |
| .numbers | Numbers Spreadsheet File | | Common |
| .nvl | UniChem Results File | | Average |
| .nyf | myBase Database File | | Average |
| .oab | Offline Address Book | | Average |
| .obj | Relocatable Object Code | | Average |
| .odb | ABAQUS Database | | Average |
| .odf | Open Document File | | Average |
| .odp | OpenDocument Presentation | | Average |
| .ods | OpenDocument Spreadsheet | | Common |
| .odx | BizTalk Server Orchestration File | | Average |
| .ofc | Open Financial Connectivity File | | Average |
| .ofm | OmniForm Form | | Average |
| .oft | Outlook File Template | | Average |
| .ofx | Open Financial Exchange File | | Average |
| .omcs | Office Manager Access File | | Uncommon |
| .omp | Office Manager Document Archive | | Average |
| .ond | Lotus Notes Encapsulated Memo File | | Average |
| .one | OneNote Document | | Average |
| .oo3 | OmniOutliner 3 File | | Average |
| .opf | FlipViewer FlipBook File | | Average |
| .opx | OrgPlus Org Chart | | Average |
| .opx | FlipAlbum Photo Album File | | Average |
| .or2 | Lotus Organizer 2 File | | Rare |
| .or3 | IBM Lotus Organizer 97 File | | Rare |
| .or4 | IBM Lotus Organizer 97 GS File | | Uncommon |
| .or5 | Lotus Organizer 5 File | | Uncommon |
| .or6 | Lotus Organizer 6 File | | Average |
| .org | Lotus Organizer File | | Average |
| .orx | RadiantOne VDS Database Schema | | Uncommon |
| .otf | OpenTuft Tufting Design File | | Average |
| .otl | NoteTab Outline File | | Average |
| .otln | Opal Outline File | | Average |
| .ots | OpenDocument Spreadsheet Template | | Average |
| .ov2 | TomTom Points of Interest Database | | Common |
| .ova | Octava Musical Score | | Average |
| .ova | Open Virtual Appliance | | Average |
| .ovf | Open Virtualization File | | Common |
| .p96 | Win96 Database File | | Average |
| .p97 | Win97 Database File | | Average |
| .pab | Personal Address Book | | Average |
| .pan | Panorama Database File | | Average |
| .pbd | ProBID+ Data File | | Uncommon |
| .pc | Personal Composer File | | Average |
| .pcap | Packet Capture Data | | Average |
| .pcb | Printed Circuit Board Design File | | Average |
| .pdas | PDAStore Data Store File | | Average |
| .pdb | Program Database | | Average |
| .pdb | Palm Desktop Database File | | Average |
| .pdb | PowerDesigner Database Backup File | | Average |
| .pdb | Protein Data Bank File | | Average |
| .pdd | Medtronic Programmer Data File | | Average |
| .pdm | PowerDesigner Database File | | Average |
| .pds | Planetary Data System File | | Average |
| .peb | ProEST+ Buildings File | | Uncommon |
| .pex | Merak Peep Data File | | Average |
| .pfc | AOL Personal File Cabinet | | Common |
| .pfl | Family Lawyer Document | | Average |
| .phm | Pro Home Manager Data File | | Average |
| .pi | Pi Calculation Data File | | Average |
| .pis | PS2DIS Project File | | Uncommon |
| .pjx | FoxPro Project | | Average |
| .pka | Packet Tracer Activity File | | Average |
| .pkb | Oracle Package Body File | | Average |
| .pkh | Oracle Package File | | Average |
| .pks | Oracle Package Spec File | | Average |
| .pkt | Packet Tracer Network Simulation Model | | Average |
| .pln | Spaceman Planogram File | | Uncommon |
| .plw | PicoLog Data File | | Average |
| .pmd | PageMaker Document | | Average |
| .pmr | Performance Monitor Report | | Average |
| .pnproj | Programmer's Notepad Project File | | Average |
| .pnpt | Programmer's Notepad Project Template | | Uncommon |
| .pod | OpenProj Project File | | Average |
| .postal | TomTom Postal Code File | | Uncommon |
| .pot | PowerPoint Template | | Average |
| .potx | PowerPoint Open XML Presentation Template | | Average |
| .pp2 | PingPlotter Data File | | Average |
| .ppf | Publisher Project File | | Average |
| .pps | PowerPoint Slide Show | | Very Common |
| .ppsx | PowerPoint Open XML Slide Show | | Common |
| .ppt | PowerPoint Presentation | | Very Common |
| .pptm | PowerPoint 2007 Macro-Enabled Presentation | | Average |
| .pptx | Microsoft PowerPoint Open XML Document | | Very Common |
| .prc | Mobipocket eBook File | | Average |
| .prf | Plot Station Plot Request File | | Rare |
| .prj | Project File | | Average |
| .prj | AIMMS Project File | | Average |
| .prm | Route 66 Map File | | Average |
| .prs | Harvard Graphics Presentation | | Average |
| .psa | Photoshop Album Catalog | | Common |
| .psf | SPI Proxy Output File | | Rare |
| .psf | PID Script File | | Rare |
| .psm | Prism Document | | Average |
| .pst | Personal Information Store File | | Average |
| .ptb | Power Tab File | | Average |
| .ptf | Scrapbook Flair Template | | Average |
| .ptk | Quicken Online Financial Data File | | Average |
| .ptm | MapPoint Map File | | Average |
| .ptt | MapPoint Map Template | | Average |
| .pub | Publisher Document | | Average |
| .pvl | Instalit Library | | Average |
| .pwd | Solid Edge Weldment Document | | Average |
| .pxj | RecordNow Project | | Average |
| .qbw | QuickBooks Data File | | Average |
| .qdf | Snapform File | | Uncommon |
| .qdf | Quicken Data File | | Common |
| .qdfm | Quicken Data File (Macintosh) | | Average |
| .qel | Quicken Electronic Library | | Average |
| .qfx | Quicken Financial Exchange File | | Common |
| .qif | Quicken Interchange Format File | | Average |
| .qpb | Quicken Payroll File | | Average |
| .qpf | Quartus II Project File | | Average |
| .qpf | Quest3D Project | | Uncommon |
| .qph | Quicken Price History File | | Average |
| .qpm | Quick Pallet Maker Input Data | | Average |
| .qpw | Quattro Pro Spreadsheet | | Average |
| .ral | WinRail Track Design File | | Average |
| .rbt | Lego MINDSTORMS NXT Program | | Average |
| .rcd | Arcade File | | Rare |
| .rcg | Recog Character Recognition Set | | Average |
| .rdb | N64 ROM Database | | Average |
| .rdf | Report Definition | | Average |
| .rdx | Reflex Data File | | Rare |
| .ret | BusinessObjects Template | | Average |
| .rf1 | Retirement Forecast File | | Average |
| .rfa | Revit Family File | | Average |
| .rge | Entourage File Archive | | Average |
| .rgn | Garmin Regional Map File | | Average |
| .rgo | RepliGo File | | Average |
| .rnq | Renque Model File | | Average |
| .rod | Actuate Report Object Design File | | Average |
| .rog | Roger 2 Input Data File | | Average |
| .roi | Report Object Instance | | Common |
| .roi | Shark Sales System Data File | | Average |
| .rou | Gerber Route File | | Average |
| .rpt | Crystal Reports File | | Average |
| .rrt | Rhapzode Resource Template | | Average |
| .rsd | RealSQLDatabase File | | Average |
| .rsw | R&R SQL Report Writer Report File | | Average |
| .rte | Navigation Route | | Average |
| .rte | Revit Project Template | | Average |
| .rvt | Revit Project File | | Common |
| .rzb | Red Zion Book File | | Average |
| .s85 | Sabre Airline Solutions Chart | | Average |
| .saf | Street Atlas USA Map File | | Common |
| .sar | Sibelius Arrange Style | | Average |
| .sav | SPSS Data File | | Average |
| .sbf | SmartBroker Data | | Average |
| .sca | Norton AntiVirus Scan File | | Average |
| .scf | DNA Sequence Chromatogram File | | Average |
| .sch | EAGLE Schematics File | | Average |
| .sdb | OpenOffice.org Base Database File | | Very Common |
| .sdb | ServerBoss Database File | | Average |
| .sdb | MonKey Office SQLite Database File | | Average |
| .sdc | OpenOffice.org Calc Spreadsheet | | Common |
| .sdf | Standard Data File | | Very Common |
| .sdf | SQL Server Compact Database File | | Average |
| .sdf | Spatial Data Format File | | Common |
| .sdp | Session Description Protocol File | | Average |
| .sdq | SAS Data File | | Average |
| .sds | OpenOffice.org Chart | | Average |
| .sds | SDS Apps Data File | | Uncommon |
| .seo | SEO Note File | | Average |
| .seq | DNA Sequence Text File | | Average |
| .ser | GeneMapper Project File | | Uncommon |
| .sgml | Standard Generalized Markup Language File | | Average |
| .shp | ESRI Shapefile | | Average |
| .shx | Shapefile Index File | | Average |
| .skc | SideKick Card File | | Rare |
| .skv | Semicolon Separated Values File | | Average |
| .skv | XLANG Schedule Drawing File | | Average |
| .skx | XLANG Schedule File | | Average |
| .sle | Sisulizer Package File | | Average |
| .slp | Sisulizer Project File | | Average |
| .soundpack | SoundPackager Sound Package | | Uncommon |
| .spo | SPSS Statistical Data Output File | | Uncommon |
| .sps | SPSS Program File | | Average |
| .spub | Disc Cover File | | Average |
| .spv | SPSS Output File | | Average |
| .sq | Sysquake Program | | Average |
| .sqd | SQ Data File | | Average |
| .sql | Structured Query Language Data | | Very Common |
| .sqlite | SQLite Database File | | Average |
| .sqr | SQL Program File | | Average |
| .sta | ABAQUS Status File | | Average |
| .stc | StarOffice Calc Spreadsheet Template | | Average |
| .stk | Stickfigure Animator File | | Average |
| .stl | Fireworks Style Library | | Uncommon |
| .stm | Exchange Streaming Media File | | Common |
| .str | dBASE Structure List Object File | | Average |
| .stt | Streets & Trips Map Template | | Average |
| .stw | STATISTICA Workbook | | Average |
| .styk | Stykz Stick Figure | | Average |
| .stykz | Stykz Animation | | Average |
| .swk | StudyWorks Save File | | Average |
| .sxc | StarOffice Calc Spreadsheet | | Average |
| .sxi | StarOffice Impress Presentation | | Average |
| .t01 | TaxCut 2001 File | | Average |
| .t02 | TaxCut 2002 File | | Average |
| .t03 | TaxCut 2003 File | | Average |
| .t04 | TaxCut 2004 File | | Average |
| .t05 | TaxCut 2005 Tax Return | | Average |
| .t06 | TaxCut 2006 Tax Return | | Average |
| .t07 | TaxCut 2007 Tax Return | | Average |
| .t2 | Textease 2000 File | | Uncommon |
| .t3001 | TARGET 3001! Circuit Design Project File | | Average |
| .tax2008 | TurboTax 2008 Tax Return | | Average |
| .tb | Tabbery Tab File | | Average |
| .tbk | ToolBook File | | Average |
| .tcx | Training Center Database File | | Average |
| .tda | Palm To-Do File | | Average |
| .tda | Java Application Thread Dump | | Average |
| .tdl | Tab Delineated Format File | | Average |
| .te | Textease CT Database File | | Common |
| .te3 | WinTrack Object File | | Average |
| .tef | TablEdit Tablature | | Average |
| .tet | Textease CT Template | | Average |
| .tfa | TreeSoft CashFlow Analysis Data File | | Average |
| .tfd | Tape Format Requirements Document | | Average |
| .tfrd | Tape Image Format Requirements Document | | Average |
| .thmx | Office 2007 Theme File | | Average |
| .tjp | TaskJuggler Project File | | Average |
| .tk3 | TK3 Multimedia eBook | | Average |
| .tkfl | TKLinks Saver Favorite Links File | | Average |
| .tmw | Translation Memory Data File | | Uncommon |
| .tol | AOL Tool File | | Rare |
| .topc | TopicCrunch Project File | | Average |
| .tpb | GROMACS Binary Input File | | Average |
| .tps | Multi Channel Measurement File | | Average |
| .tr3 | TomeRaider eBook File | | Average |
| .tra | WinTrack Railroad Track File | | Average |
| .trd | TrID Definitions Package | | Average |
| .trs | Rosetta Stone Language Data | | Common |
| .trs | WinTrack Railroad Track Text File | | Average |
| .tst | TestPoint Test File | | Average |
| .tsv | Tab Separated Values File | | Common |
| .ttk | Catalyst Translation Toolkit | | Average |
| .txa | Midas ViewPoint Text Array List | | Average |
| .txd | Game Texture Dictionary | | Average |
| .txf | Tax Exchange Format | | Average |
| .udb | Dynamics AX User Database File | | Average |
| .ulf | Universal List File | | Average |
| .ulz | USBlyzer Data Capture File | | Average |
| .upoi | iGO Points of Interest File | | Average |
| .uvf | Uncertain Value Format | | Average |
| .val | Values List | | Average |
| .val | Valodas Dictionary File | | Uncommon |
| .vcd | Value Change Dump File | | Average |
| .vce | Visual CertExam Exam File | | Average |
| .vcf | vCard File | | Very Common |
| .vcs | vCalendar Event File | | Average |
| .vdx | Visio Drawing XML File | | Average |
| .vi | LabVIEW Virtual Instrument File | | Average |
| .vmt | Valve Material File | | Average |
| .voi | VOI Group File | | Average |
| .vok | PocketVok Vocabulary File | | Average |
| .vrd | Visio Report Definition File | | Average |
| .vscontent | Visual Studio Content File | | Average |
| .vsx | Visio Stencil XML File | | Average |
| .vtx | Visio Template XML File | | Average |
| .vxml | VoiceXML File | | Common |
| .wab | Windows Address Book | | Common |
| .wdb | Microsoft Works Database | | Average |
| .wdq | Offline Explorer Queue File | | Uncommon |
| .wea | Ecotect Weather File | | Average |
| .wfm | dBASE Form | | Uncommon |
| .wgp | Web Gallery Project | | Average |
| .wgt | XNBC Synaptic Weights File | | Average |
| .wgt | IMPS Data File | | Average |
| .wjr | ReGet Deluxe Data File | | Average |
| .wk1 | Lotus Worksheet | | Average |
| .wk2 | Lotus 2 Worksheet | | Average |
| .wk3 | Lotus 3 Worksheet | | Average |
| .wk4 | Lotus 4 Worksheet | | Average |
| .wk5 | Lotus 5 Worksheet | | Average |
| .wki | Lotus 2 Worksheet | | Average |
| .wks | Microsoft Works Spreadsheet | | Very Common |
| .wks | Lotus 1-2-3 Spreadsheet | | Average |
| .wku | Lotus 1-2-3 Spreadsheet | | Average |
| .wmdb | Windows Media Database File | | Average |
| .wor | MapInfo Workspace File | | Average |
| .wpf | WordPerfect Form | | Average |
| .wtb | Win-Test Binary Log File | | Average |
| .wtr | Encarta File | | Rare |
| .xdb | PowerDesigner Database Definition File | | Average |
| .xdp | XML Data Package | | Average |
| .xef | eManager Form Data | | Average |
| .xem | PowerDesigner Model definition File | | Average |
| .xfo | XSL-FO Formatted Form | | Average |
| .xft | Adobe Form Designer 5.0 File | | Average |
| .xl | Excel Spreadsheet | | Average |
| .xlc | Excel Chart | | Average |
| .xlgc | ExpressK Database File | | Uncommon |
| .xlr | Microsoft Works Spreadsheet | | Average |
| .xls | Microsoft Excel Spreadsheet | | Very Common |
| .xlsb | Excel Binary Workbook | | Average |
| .xlsm | Excel 2007 Macro-Enabled Spreadsheet | | Average |
| .xlsx | Microsoft Excel Open XML Document | | Very Common |
| .xlt | Microsoft Excel Template | | Average |
| .xltm | Excel 2007 Macro-Enabled Spreadsheet Template | | Average |
| .xltx | Excel 2007 Spreadsheet Template | | Average |
| .xlw | Microsoft Excel Workbook | | Average |
| .xmcd | Mathcad Worksheet File | | Average |
| .xml | XML File | | Very Common |
| .xmlper | LeCroy Binary Waveform File | | Average |
| .xpg | Autoplay Media Studio Exported Page | | Average |
| .xpj | Micro Planner X-Pert Project File | | Average |
| .xpm | Micro Planner Manager File | | Average |
| .xpt | SAS Transport File | | Average |
| .xrp | RationalPlan Project File | | Average |
| .xsl | XML Style Sheet | | Common |
| .xslt | XSL Transformation | | Average |
| .xsn | InfoPath Form Template File | | Uncommon |
| .xtp | XTree Data File | | Rare |
| .xxd | Brixx Planner Calendar | | Rare |
| .yam | Yahoo! Auctions Data | | Average |
| .zap | Zone Alarm Pro Data File | | Average |
| .zdb | Quicken Online File | | Average |
| .zdb | EPSQ Database | | Average |
| .zdc | CD Catalog Expert Database File | | Average |
| .zix | Quicken Online File | | Average |
| .zpl | Zoom Player Play List | | Average |
| .^^^ | Pervasive SQL Database File | | Average |
| .~hm | HostMonitor Backup TestList File | | Average |
