1 Go = 1 000 000 Ko.

From July 2008 to March 2021, there is confusion in the minds of many.
However, the definitions are simple, clear, and precise (aren't they, Brou?):

The bit, abbreviation b, is the basic binary unit in computing, and is worth 0 (zero) or 1 (one).
The octet, abbreviation o, called in English byte, abbreviation B, is made up of 8 bits;
it can take values from 0 to 255 (because 2^8=256).
1 ko (kilobyte) is worth 1,024 bytes (and not 1,000 bytes)
1 Mo (megabyte) is worth 1,024 x 1,024 = 1,048,576 bytes (and not 1,000,000 bytes)

One just needs to apply these definitions, without trying to quibble or dispute...

--
Retirement is great! Especially in the Caribbean...
Raymond (INSA, AFPA)

The numbers provided by fdwrc are not very precise.
Here is the exact conversion: 1 GB = 1024 MB = 1024 * 1024 KB = 1,048,576 KB
1 GB = 1 Go
4 GB = 4 Go = 4 * 1,048,576 KB = 4,194,304 KB
1 Gb = 1/8 GB = (1/8) * 1,048,576 KB = 131,072 KB

working for Belgacom, I can tell you that 1GB is worth 1024 MB
1048576 KB
1073741824 Bytes