1 GB = 1 GiB when you don't know what you're dealing with: take a look at the 1.44 MB floppy per example.
1.44 MB = 1.44 B * 1000 * 1024
1.44 MB = 1.44 B * 1000 * 1024
Now I realize that they mixed 2^10 and 10^3 in the same sentence. Thanks for finally answering a question that's been in the back of my brain for 20+ years!