The Backrooms is usually treated as effectively enormous, and in many versions of the lore, infinite. In fan discussions, one common estimate for the “original” Backrooms area is about 600 million square miles , though that number is not official canon and changes by level and by interpretation.

What that means

  • If you use the 600 million square mile estimate, the Backrooms would be about 3 times the area of Earth.
  • Some community posts treat the whole setting as much bigger than that by adding up levels and variants, but those numbers are speculative and not standardized.
  • The wiki-style canon does not enforce one fixed size, so the answer depends on which version of the Backrooms you mean.

Simple takeaway

If someone asks “how big is the Backrooms?”, the safest answer is: it’s either vast beyond realistic measurement or outright infinite, depending on the source. For the most commonly repeated fan estimate, think hundreds of millions of square miles.

Tiny note

The most discussed figure online is the 600 million square mile claim, but it’s a fan-lore number rather than a confirmed official measurement.