Package Size Calculator

Estimate installed size versus download size for a software package and its dependencies.

About Package Size Calculator

Package managers report both a download size (the compressed .deb/.rpm archive transferred over the network) and an installed size (the actual disk space consumed once files are extracted) — `apt show <pkg>` and `dnf info <pkg>` both display these separately. The ratio between them reflects how compressible the package's contents are: text-heavy packages (documentation, scripts, source) compress well and show a high ratio, while packages dominated by already-compressed binaries or media compress poorly. Planning disk capacity for an install or upgrade should always use installed size, not download size.

Formula

Compression ratio

compression_ratio = installed_size / download_size

Worked example

With the default values below, Package Size Calculator returns Installed:Download Ratio of 3.20. Change any input above and every figure here is recalculated in your browser.

Inputs used

Download (Compressed) Size (MB)minimum 0.01: 25
Installed (Uncompressed) Size (MB)minimum 0.01: 80
Number of Such Packages (for batch estimate)minimum 1: 1

Results

Installed:Download Ratio: 3.20
Space Expansion on Install (MB): 55.0
Total Download Size (all packages): 25 MB
Total Installed Size (all packages): 80 MB

Step by step

1Values used
2Compression ratio
3Installed:Download Ratio= 3.20
4Space Expansion on Install (MB)= 55.0
5Total Download Size (all packages)= 25 MB
6Total Installed Size (all packages)= 80 MB

Assumptions and limits

The result is derived only from the 3 inputs listed above. Anything not among them is not part of the calculation.
In particular, this calculator does not take inflation, tax or compounding frequency into account.
Figures are rounded for display to 2 decimal places, so totals built from several rounded parts can differ slightly from the unrounded arithmetic.

How these calculators are built and tested is described on the Methodology page. If a figure looks wrong, please report it.

Frequently Asked Questions

Why is a package's installed size always larger than its download size?

The download is a compressed archive (typically xz, gzip, or zstd-compressed within the .deb/.rpm container format), while the installed size reflects the actual uncompressed files written to disk — compression ratios of 2-4x are common depending on content type.

How do I check a package's download and installed size before installing?

On Debian/Ubuntu, `apt show <package>` lists both 'Download-Size' and 'Installed-Size'. On Fedora/RHEL, `dnf info <package>` shows only installed size directly, but `dnf install --downloadonly --assumeno <package>` reports the download size for planning bandwidth.

Does disk space planning need to account for both cached and installed copies?

Yes — during installation, both the downloaded archive (cached under /var/cache/apt or /var/cache/dnf) and the extracted installed files temporarily coexist on disk, so peak disk usage during an install briefly exceeds installed size alone by roughly the download size, until cache cleanup.