Size discrepancy due to GB and GiB

Situation

You might see a size discrepancy between the files on your hard drive, in the cloud, and in our backup applications. This discrepancy normally occurs because the source and target locations use different definitions of a gigabyte.

Cause

Windows OS and our backup software use the binary definition of a gigabyte, which means that they consider 1 GB to equal 1,073,741,824 bytes, while macOS (starting with version 10.6) and some cloud storage providers, for example, Backblaze B2, consider 1 GB to equal 1,000,000,000 bytes.

Because of that, the same file will have a size of 1 GB in AWS S3 storage, but 1.1 GB in Backblaze. The difference increases with the amount of data: 476 GB of files on Windows OS will take 512 GB of space on Mac. The actual size of the files does not change, only the way it is calculated does, so this particular situation does not require any action.