Why are zip file sizes different in finder compared to Google or Amazon Drive? I was wondering why file sizes of my zipped archives (.zip) are inconsistent. A file that shows in the finder (macOS) as 9.17 GB shows up as being 8.54 GB on an Amazon Drive (same thing with Google Drive).
This is because Apple uses base-10 instead of base-2 to display file size. Base-2 will consider 1GB to equal 1,073,741,824 bytes, where a base-10 system, like Apple's, will consider 1GB to mean 1,000,000,000 bytes. In fact, the base-2 and base-10 prefixes are different, using the term gibibyte and gigabyte to represent GB, respectively (GiB can be used to unambiguously denote gibibyte).

9.17 Gigabytes is 8.54 Gibibytes, so the zip files are actually the same size.

Further reading:

https://blog.macsales.com/1852-snow-leopard-changes-they-way-we-look-at-gigabytes-and-megabytes-and-kilobytes-as-well

https://en.wikipedia.org/wiki/Gibibyte

https://en.wikipedia.org/wiki/Gigabyte#Consumer_confusion