Also, when it comes to SD cards -- just like in hard drives/optical media for computers -- there's a bit of skulduggery involved. Technically every step in the kilo/mega/tera-byte is 1024 units, but the manufacturers measure them in units of 1000. Which is why you'll see DVD media listed as 4.7GB but they'll only hold 4.5GB. Formatting takes up some space, but the rest of it are those missing 24 bytes per KiloByte.