Mebibytes to gibibytes (MiB to GiB)

One mebibyte is exactly 0.0009765625 gibibytes. That is the definition of the prefixes, not a measurement: the decimal SI prefixes (kilo, mega, giga, tera) step by exactly 1,000, and the binary IEC prefixes (kibi, mebi, gibi, tebi) step by exactly 1,024. The two families are both exact; the trouble is only that software and storage labels do not always say which one they mean.

Worked through: 1,536 MiB x 0.0009765625 = 1.5 GiB.

Going the other way, one gibibyte is 1,024 mebibytes.

For mental arithmetic: Divide by 1,024. 512 MiB is 0.5 GiB and 1,536 MiB is 1.5 GiB.

Both units are binary, so the factor is exactly 1/1,024 with no decimal-versus-binary question at all. This is the conversion for memory settings, which are written in whichever unit is shorter: a container limit of 1536Mi is 1.5 GiB, a Java heap of 3072m is 3 GiB, and 512 MiB is exactly half a gibibyte. Mixing this up with MB to GB, which divides by 1,000, makes 1,536 into 1.536 instead of 1.5, an error of 2.4%.

Precision is worth matching to the input. A measurement given as 256 MiB carries one or two significant figures, and reporting its conversion to six implies a precision the original never had.