Which gallon is used?

Both are listed: the US gallon (3.785 L) and the UK imperial gallon (4.546 L).

KB, MB and GB are decimal (1000). KiB, MiB and GiB are binary (1024), which is what most operating systems show.

Unit Converter — Free, private, in-browser

From

To 3.280839895

All length units

Millimetre1000

Centimetre100

Metre1

Kilometre0.001

Inch39.37007874

Foot3.280839895

Yard1.093613298

Mile0.0006213711922

Nautical mile0.0005399568035