Show Compression Ratio with Unrar Command
This article explains how to determine the exact compression ratio of
files stored within a RAR archive using the command-line utility
unrar. By utilizing specific listing flags, you can inspect
the uncompressed size, compressed (packed) size, and the resulting
compression ratio for individual files as well as the entire
archive.
To display the compression ratio of files within a RAR archive, use the verbose list command:
unrar v archive.rarAlternatively, the standard list command also displays this information:
unrar l archive.rarUnderstanding the Output
When you run unrar v archive.rar, the command outputs a
tabular view of the archive contents containing several columns:
- Attributes: File permissions and file system flags.
- Size: The uncompressed size of the file in bytes.
- Packed: The compressed size of the file as stored inside the archive.
- Ratio: The compression ratio shown as a percentage
(calculated as
Packed Size / Uncompressed Size * 100). - Date & Time: File modification timestamps.
- Checksum: CRC32 checksum of the file.
- Name: The relative file path.
At the bottom of the output table, unrar prints a
summary line showing the total uncompressed size, total packed size, and
the overall compression ratio for the entire archive.
Viewing Detailed Technical Information
If you require a detailed per-file breakdown rather than a table, use the technical list command:
unrar lt archive.rarThis command outputs a block of metadata for each archived item, explicitly stating the original size, packed size, and exact compression ratio on individual lines, making it ideal for automated parsing and scripting.