steam-library-size

How big would your Steam library be if you installed every game you own?

Steam only knows the size of games you've already installed. SteamDB's calculator doesn't do install sizes, and the old web calculators are dead — and they needed a public profile anyway. This tool answers the question locally: it reads the license cache your own Steam client already has on disk, then asks Steam anonymously for each game's depot sizes. No API key. No public profile. Works with fully private accounts.

Install

You need: Python 3.10 or newer, and Steam installed on the same machine (logged in at least once — that's what writes the license cache this tool reads). Your games do not need to be installed.

The recommended installer is pipx — it's like pip, but it puts command-line tools in their own isolated environment so they can't break (or be broken by) anything else on your system.

Windows

1. Install Python from python.org/downloads — on the first installer screen, tick "Add python.exe to PATH".
2. Open a new Command Prompt (or PowerShell) and run:

   py -m pip install --user pipx
   py -m pipx ensurepath
   

3. Close and reopen the terminal (that's what makes the new PATH take effect), then:

   pipx install steam-library-size
   

Linux

Install pipx from your package manager, then install the tool:

# Debian/Ubuntu:  sudo apt install pipx
# Fedora:         sudo dnf install pipx
# Arch:           sudo pacman -S python-pipx
pipx ensurepath

Close and reopen the terminal, then:

pipx install steam-library-size

macOS

brew install pipx
pipx ensurepath

Close and reopen the terminal, then:

pipx install steam-library-size

Just want a single script to read and run?

The whole tool also exists as one plain Python file: standalone/steam_library_size.py. Download it, install its two dependencies, and run it:

python3 -m pip install vdf "steam[client]"
python3 steam_library_size.py

Same behavior, same flags. A test in CI keeps it byte-for-byte in sync with the packaged version.

No pipx? Plain pip works too

python3 -m pip install --user steam-library-size    # Windows: py -m pip install --user steam-library-size

Troubleshooting

• steam-library-size: command not found — you didn't reopen the terminal after pipx ensurepath (or skipped it). Reopen and try again.
• pipx: command not found right after installing it — same fix: new terminal.
• error: Could not find a Steam install — start Steam once and log in, or pass the location yourself: steam-library-size --steam-dir "D:\Steam".

Usage

Just run it:

steam-library-size

Real output from a real library:

Your Steam library: 288 games
Installed all at once, that's 6,401.0 GB (6.25 TiB).
An 8 TB drive would hold the lot.

  Games: 6,401.0 GB   DLC: 8.7 GB   Other (tools/demos/etc): 545.2 GB

Top 5 biggest games:
      572.6 GB  Call of Duty®
      496.6 GB  ARK: Survival Evolved
      208.2 GB  iRacing
      182.1 GB  Arma 3
      180.5 GB  FINAL FANTASY VII REBIRTH

8 apps with no size data (usually delisted or test apps).

Options

Progress goes to stderr, so --json/--csv pipe cleanly.

How it works

Your Steam client keeps a cache of every license on your account in appcache/packageinfo.vdf. The tool parses that file to get the full list of app IDs you own, then makes one anonymous connection to Steam's product-info service (the same PICS system the Steam client uses) to fetch each app's depot manifest sizes, and sums the public-branch, English, your-platform depots per app.

Accuracy caveats

• Sizes are fresh-install sizes today (uncompressed public-branch depots). Games with optional depots — every Call of Duty mode, all ARK maps, HD texture packs — count all of them, so those over-report a typical install.
• Shader cache, save games, and workshop content are not included.
• Owned-but-delisted apps may have no size data; they're counted and reported as such, never silently dropped. Same for apps that fail to fetch.

Privacy

Nothing about your account leaves your machine. The only network traffic is an anonymous (not-logged-in) Steam connection querying public app metadata by app ID — the same data any Steam client can see.

Platform support

• Linux: verified, including Flatpak and Snap Steam installs.
• Windows / macOS: path detection implemented and unit-tested, but not yet verified on real machines — issues and reports welcome.

License

MIT — see LICENSE.