What is the SFV file format?
An .sfv file is a checksum file used for verifying data. It stores CRC-32 checksum values for files, folders, or disks (including CD/DVDs).
The .sfv format uses the CRC-32 algorithm: each line in the plain-text file pairs a filename with its 8-digit hex checksum (e.g. archive.r01 1A2B3C4D); lines starting with ; are comments.
.sfv files identify any file whose checksum does not match the value stored in the .sfv, determining whether given files were modified. They cannot be used for verifying file authenticity, however - CRC-32 is weak enough that collisions can be forged. For security use SHA-256 checksums instead.
.sfv files are typically used during disk copy processes, in CD/DVD burning, or to check the integrity of files downloaded from the internet. They remain common in Usenet and scene releases, often paired with PAR2 repair archives.
Security & safety
RISK: LOWAn SFV is a tiny passive text file - it contains no code and cannot run anything, so opening one is safe. The real caveat is conceptual, not malware: CRC-32 verifies only that files weren't accidentally corrupted, NOT that they're authentic. A CRC-32 checksum is easy to forge, so an SFV that 'passes' does not prove a download is genuine or malware-free - for that you need SHA-256 or a signature. Also be wary of fake 'SFV viewer' downloads pushed by ad-laden portals; get tools only from the official sites above.
Format details
in a nutshellPrograms that open SFV files
Windows4 apps
QuickSFV
Free Double-click the .sfv; QuickSFV recomputes CRC-32 for every listed file and shows OK/failed per file. Can also create SFV files. 
7-Zip
Open-source 7-Zip can compute CRC-32 (right-click > CRC SHA) to compare against the values listed in the SFV manually. 
TeraCopy
Freemium Use TeraCopy's verify feature, or right-click an .sfv to test the listed files' checksums after a copy.
RapidCRC Unicode
Open-source Open the .sfv to verify CRC-32 (and MD5/SHA) with full Unicode filename support; create SFV files too. 
macOS2 apps
checkSum+
Free Drag the .sfv (with its files) into checkSum+ to verify CRC-32 entries; can also generate SFV/MD5/SHA lists.
cksfv (Homebrew)
Open-source Install via Homebrew, then 'cksfv -f file.sfv' in Terminal to verify the listed files. 
Linux2 apps
cksfv
Open-source Run 'cksfv -f file.sfv' to verify, or 'cksfv *.rar > files.sfv' to create one. The standard CLI tool.
GtkHash / 7z
Open-source Compute CRC-32 with GtkHash (GUI) or '7z h' and compare to the SFV's listed values. Technical details
deep spec| Checksum algorithm | CRC-32 (IEEE 802.3/ANSI X3.66, polynomial 0xEDB88320 reflected) |
| Checksum width | 32 bits, written as 8 hexadecimal digits per file entry |
| Line syntax | filename<space>8-hex-CRC32 - one entry per line; no other delimiters or quoting |
| Comment syntax | Lines beginning with ';' are ignored as comments; tools typically insert a generated-by header |
| File encoding | ASCII; modern tools accept UTF-8 to support non-ASCII filenames |
| File signature | None - no binary magic bytes; format is identified by .sfv extension and plain-text structure |
| MIME type | text/plain |
| Typical file size | Under 1 KB to a few KB; approximately 30-50 bytes per listed file |
| Filename scope | Basenames only by convention; subdirectory paths are not part of standard usage |
| Error detection | Detects accidental corruption (transmission errors, media defects); CRC-32 collisions are easily crafted, making it unsuitable for tamper detection |
| Entry count limit | No defined maximum; a single .sfv file can list thousands of files |
| Platform support | Windows, macOS, Linux, Unix - plain ASCII text is universally readable |
| Typical companion files | Distributed alongside .par2 repair sets in Usenet/scene releases; also found with multi-part .rar archives |
| Released | Mid/late 1990s (Win-SFV utility; popular in Usenet/warez/scene distribution) |
| Latest version | No formal version; the de facto convention (filename + 8-hex CRC32, ';' comments) is stable |
| Open standard | Yes · royalty-free |
| Specification | en.wikipedia.org |
SFV conversions
Community Q&A
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