I bought a USB flash drive. It has 4.5/5 stars on Amazon with 2000 ratings. The packaging says 128 GB. However, as I'm formatting it using the Disks utility on Linux, it tells me that the drive is only 125,829,120,000 bytes. Is this normal?

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Note that the utility spells out the actual number of bytes. This does not seem to be a case of the 1000 vs 1024 mix-up. If it were, it would be 7% short instead (1e9 / 1024^3 = 0.93)

Also note that the filesystem size (NTFS) is only 1MB = 0.001% smaller than the drive size.

This was actually a package with 2 drives, and they seem to be identical.

  • Could be a case of marketing rounding-up the capacity to a power-of-two. The capacity of storage devices have typically been manipulated to advertise the largest possible number. There used to be the unformatted versus formatted controversy. Then the 1024 versus 1000 base for "KB".
    – sawdust
    Oct 27 at 8:49
  • Your post would be less confusing if the flash drive contained no partitions. Then there would simply be just the capacity of the entire drive to focus on.
    – sawdust
    Oct 27 at 9:00
  • 9
    Observation: you got 120*1000*1024*1024. Oct 27 at 11:26
  • 2
    They must be using a drivemaker's GB
    – Erbureth
    Oct 27 at 15:48

This is normal, on every flash drive, there is some data allocated by the system (boot data, file system...) and the user can't use that space


I find this to be common on flash media. I've got a 256GB stick here that is 247,593,959,424 bytes (90.07%), and a 64GB SSD that is 62,813,896,704 bytes (91.4%).

I suspect the cited size is the chip size (and is binary), and that the actual size is after the wear leveling overhead and replacement blocks are removed.

  • Maybe they are counterfeit?
    – MWB
    Nov 28 at 5:31

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