| pi | iPi Calculation Data |
| pib | Platform Independent Binary |
| picd | ProfiCAD Integrated Circuit Document |
| picon | Dreambox Picon File |
| pidb | MonoDevelop Parser Information Database |
| pigm | Indigo Packed Material Data |
| pigs | Indigo Renderer Packaged Scene |
| pik | Protel 99 Pick and Place Data |
| pike | Pike Source Code |
| pin | BLAST Protein Database |
| piw | PI ProcessBook Data |
| pix | SmartWare Physical Index |
| pj | Project64 Saved State File |
| pj1 | Project64 Saved State File |
| pj2 | Project64 Saved State File |
| pjb | IBM InfoSphere Information Server Manager Data |
| pjd | Portfolio Exported Categories Data |
| pjf | Photojunction File |
| pjf | iAddress Postal Job File |
| pjl | HP Printer Job Language Data |
| pjnz | Spectrum Projection Data |
| pjtf | Portable Job Ticket Format Data |
| pjv | Velocity User Selections Data |
| pk | Adobe Audition v3 Peak File |
| pka | Cisco Packet Tracer Activity File |
| pkb | Blackberry Password Keeper Encrypted Backup |
| pkb2 | Blackberry Password Keeper Encrypted Backup |
| pkc | Jython JAR Cache |
| pkcs12 | PKCS #12 Data File |
| pkcs7 | PKCS #7 Certificate Data |
| pkd | Eurotherm Encrypted Hydra History Data |
| pkf | Adobe Audition Peak File |
| pkgx | Microsoft UE-V PKGX Data |
| pki | LibVirt PKI Data |
| pkj | PokerJuice Data |