File extensions start with character 'H'
| File Type | Category | File Format | |
|---|---|---|---|
| .h | Development Files | C/C++ Header File | |
| .h264 | Digital Video Files | H.264 Encoded Video File | |
| .h2o | Archive Files | Battle Realms Game Data File | |
| .h3m | Game Files | Heroes 3 Map File | |
| .ha | Compressed Files | HA Compressed Archive | |
| .hal | Development Files | HansaWorld Application Language File | |
| .hbc | Compressed Files | HyperBac Compressed Archive | |
| .hbc2 | Compressed Files | HyperBac Compressed File Archive | |
| .hbe | Compressed Files | HyperBac Compressed and Encrypted Archive | |
| .hbx | Encrypted Files | BinHex Encoded File | |
| .hcc | Data Files | HydroCAD Prefab Chamber Data File | |
| .hce | Data Files | HydroCAD Hydrograph Data File | |
| .hci | Data Files | HydroCAD IDF Data File | |
| .hcl | Data Files | HotDocs Clause Archive | |
| .hcr | Data Files | HydroCAD Rainfall Curve Data File | |
| .hcu | Data Files | Hydrograph Units Definitons File | |
| .hcx | Data Files | ChartXL Chart | |
| .hda | Data Files | HotDocs Auto-Assemble File | |
| .hdb | Database Files | HansaWorld Database File | |
| .hdf | Data Files | Hierarchical Data Format File | |
| .hdi | Disk Image Files | Hard Disk Image | |
| .hdl | Data Files | HotDocs Library File | |
| .hdpmx | Data Files | HotDocs Publisher Mapping XML File | |
| .hdr | Raster Graphics Files | High Dynamic Range Image File | |
| .hds | Windows Files | Microsoft PlayReady Data File | |
| .hdumx | Data Files | HotDocs User Mapping XML File | |
| .hdz | 3D Graphics Files | Compressed Poser Hand Pose File | |
| .hex | Multiple Use Files | Hexadecimal Source File | |
| .hht | Text Files | Help and Support Center HHT File | |
| .hif | Data Files | Quicken Online File | |
| .hip | 3D Graphics Files | Houdini Project File | |
| .hkdb | Data Files | Apple iTunes Library File | |
| .hki | Compressed Files | WinHKI Archive | |
| .hki1 | Compressed Files | WinHKI HKI1 Archive | |
| .hki2 | Compressed Files | WinHKI HKI2 Archive | |
| .hki3 | Compressed Files | WinHKI HKI3 Archive | |
| .hl | Data Files | HeuristicLab Storage File | |
| .hlb | Multiple Use Files | VMS / VAX Help Library | |
| .hm | Backup Files | HostMonitor File | |
| .hm3 | Data Files | Help & Manual 3 Project | |
| .hma | Audio Files | Sony HI-MD Audio File | |
| .hml | Data Files | HostMonitor TestList File | |
| .hmt | Data Files | HighMAT File | |
| .hmxp | Data Files | Help & Manual XML Project | |
| .hmxz | Data Files | Help & Manual Compressed Project | |
| .hog | Game Files | Descent Mission File | |
| .hpf | Development Files | High Performance Fortran File | |
| .hpi | Raster Graphics Files | Hemera Photo Objects Image File | |
| .hpk | Game Files | Tropico Game Archive | |
| .hpk | Compressed Files | HPack Compressed Archive | |
| .hpp | Development Files | C++ Header File | |
| .hqx | Encrypted Files | BinHex 4.0 Encoded File | |
| .hs | Development Files | Haskell Script | |
| .hs2 | Data Files | HyperRESEARCH 2 Study File | |
| .hst | Data Files | History File | |
| .ht | Configuration Files | HyperTerminal Session File | |
| .htb | Data Files | Audacity Help File | |
| .htg | Data Files | HackTheGame Mission Pack | |
| .htm | HTML Files | Hypertext Markup Language File | |
| .html | HTML Files | Hypertext Markup Language File | |
| .htmlz | HTML Files | Zipped HTML eBook | |
| .huh | Data Files | HydroCAD Unit Hydrograph Definitions File | |
| .hvc | Data Files | HotDocs Variable Collection File | |
| .hwp | Text Files | Hanword Document | |
| .hy1 | Data Files | Ventura Publisher Hyphenation File | |
| .hyp | Partially Downloaded Files | Dictionary Information File | |
| .hyv | Data Files | Team Manager Meet Event File | |
| .hz | Text Files | Chinese (Hanzi) Text |