Size discrepancy due to GB and GiB


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 the target locations use a different definition of a gigabyte.


Windows OS and our backup software use binary definition of a gigabyte, which means that they consider 1GB to equal 1073741824 bytes, while Mac OS (starting with 10.6 version) and some cloud storage providers, for example Backblaze B2, consider 1GB to equal 1000000000 bytes.

Because of that, the same file will have a size of 1GB in AWS S3 storage, but 1.1GB in Backblaze. The difference increases with the amount of data: 476GB of files on Windows OS will take 512GB 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.