Fallout 1 originally took about 500 MB of disk space, with several sources putting the installed size in the 480–550 MB range depending on version and install method.

Quick Scoop

  • A GOG forum post reports Fallout 1 at 483 MB downloaded , with the store listing it around 506 MB.
  • A fan forum post says a fresh installation takes about 545 MB.
  • A Reddit post notes that some modern storefronts may show around 2 GB or more because of packaging or platform overhead, not because the original game was that large.

Practical answer

If you just want the classic game’s actual space use, think roughly half a gigabyte.

If you want the store/download size on a modern platform, it can look bigger than that because of launcher and distribution differences.