What is the PRC file format?
The .prc format is used for various purposes; most commonly it is the Mobipocket eBook File format. Structurally, a .prc ebook is identical to a .mobi file - both use the Palm Database (PDB) container with the BOOKMOBI type/creator tag at byte offset 60. The .prc extension originated on Palm OS, which only supported .prc and .pdb extensions natively, so Mobipocket books were distributed as .prc on Palm devices.
The files can be saved in both unprotected and DRM-protected formats. Protected .prc files limit the file from being opened on unauthorized systems or devices. Unprotected files can be viewed without any restriction. In addition to desktops, .prc ebooks can be read on smartphones, tablets, and older Kindle devices; Amazon hardware and software supported the format until 2022, when Amazon deprecated .prc/.mobi from its Send to Kindle service.
Since 2022, EPUB is the recommended format for Kindle submissions. Older .prc collections remain accessible through Calibre - which treats .prc and .mobi as identical - and through apps such as FBReader, Cool Reader, and Moon+ Reader.
Security & safety
RISK: LOWA .prc Mobipocket ebook is document data and safe to read. The main friction is DRM: Amazon-purchased AZW/PRC books are account-locked, so generic apps refuse them and conversion is blocked - a rights restriction, not a virus. Removing DRM violates Amazon terms and may be unlawful. Download .prc files only from reputable sources (Project Gutenberg, Manybooks, Feedbooks for DRM-free); pirated ebook sites often bundle adware or fake installers.
Format details
in a nutshell- Corel Presentations Document - Corel Presentations (part of WordPerfect Office) uses .prc for its proprietary slide presentation format; unrelated to ebooks.
- PTC Creo / Pro/ENGINEER Part File - PTC Creo (formerly Pro/ENGINEER) CAD software uses .prc for 3D part files; the ISO 14739-1 PRC format is also used in PDF 3D annotations.
- Bryce Preset File - DAZ Studio / Bryce uses .prc for preset/content files; a different proprietary binary format.
Programs that open PRC files
Windows3 apps
Calibre
Open-source Add the .prc to the Calibre library (drag & drop); it appears as a MOBI book. Double-click to read, or Convert to change format. DRM-free files only. 
macOS3 apps
Linux2 apps
Android3 apps
Technical details
deep spec| Container format | Palm Database (PDB) - structurally identical to .mobi |
| Magic bytes | ASCII 'BOOKMOBI' (hex: 42 4F 4F 4B 4D 4F 42 49) at byte offset 60 - PDB type 'BOOK' + creator 'MOBI' |
| Byte order | Big-endian |
| Body encoding | Binary |
| Compression | PalmDOC (LZ77-based) per record, HUFF/CDIC for newer Mobipocket content, or optionally uncompressed |
| DRM options | Open (DRM-free), Mobipocket DRM, or Kindle DRM on AZW variants; DRM voucher stored as a trailing PDB record |
| Metadata block | EXTH block (author, ASIN, cover image, publisher) embedded in PDB Record 0 after the MOBI header |
| MOBI format version | Version field in MOBI header: 1-3 (Mobipocket classic), 6 (KF6/Kindle), 8 (KF8 HTML5 content in AZW3 hybrid) |
| Typical file size | 100 KB-20 MB (typical novel 0.5-5 MB; illustrated books larger) |
| Extension origin | Palm OS only supported .prc and .pdb extensions; Mobipocket adopted .prc for Palm OS distribution |
| Relation to .mobi | .prc and .mobi are structurally identical; only the file extension differs - Calibre treats them as the same format |
| Deprecation status | Amazon deprecated .prc/.mobi from Send to Kindle in 2022; EPUB is now the recommended Kindle submission format |
| MIME type | application/x-mobipocket-ebook |
| Released | 2000 (Mobipocket Reader for Palm OS); .prc extension from PalmOS convention |
| Latest version | Retired - Amazon deprecated MOBI/PRC from Send to Kindle in 2022 |
| Specification | wiki.mobileread.com |
PRC conversions
Community Q&A
asked by usersNo questions yet - be the first to ask about PRC files.
