Why is my storage media smaller than advertised in Windows?

Divyam November 14, 2010

I use Windows 7 32-bit Core2Duo 2GB RAM.

When I use a USB of 4 GB, it gives only 3.7 GB.
And at my 500 GB hard drive is only 465 GB.
How do I repair?

I feel this is a common Windows problem.

  1. Oron Joffe
    November 15, 2010 at 3:17 pm

    Tina is right. Another issue is that when you format a disc, you use some of the space on it for storing the file system information. Things are actually much better nowadays than they used to be - in the days of floppy discs you would have lost 33%!

  2. Vijay C
    November 15, 2010 at 4:32 am

    I Think it is right, what above solution

  3. Tina
    November 15, 2010 at 1:57 am

    Divyam, we have had a similar question before, but I cannot find it now. I will add the link later.Anyways, I know the answer. This is not a problem with Windows. But you're right, it is very common. However, it's a logical phenomenon. 1 GB is equal to 1024 MB. This is a fact of digital data storage and this is how Windows calculates. However, when hardware manufacturers advertise size, they calculate with 1000 MB per 1 GB. So as you can see, there is a difference of 24 MB. When you multiply that by 4 or 500, it becomes quite a big difference. For once Windows is not to blame.Let us know whether this answer made sense to you. Thank you!

    • timmyjohnboy
      November 15, 2010 at 5:23 am

      I've personally always thought this to be false advertising and ought to stop.

      • Mike
        November 15, 2010 at 6:30 pm

        The size advertised by manufacturers is correct.

        Manufacturers state the raw unformatted space because that's how the hard disks are shipped ~unformatted~.
        Since they have to calculate the size of the disk somehow they are using SI units, which are unfortunately in decimal (Base-10)
        Kilo = 10^3 = 1000, Mega = 10^6, Giga = 10^9

        Operating systems on the other hand usually calculate in binary code (Base-2)
        Kilo = 2^10 = 1024, Mega = 2^20, Giga = 2^30

        there you go, poor little Gigabytes :) and then there is another portion of disk space lost because you have to format the drive and file systems are some nasty little space-eating buggers ~ that's the whole magic behind the "missing disk space"

        FYI those complaints about "missing space" was the reason for Apple to change the calculation of disk space to Base-10 in Mac OS X 10.6

        • timmyjohnboy
          November 15, 2010 at 6:59 pm

          Good explanation, but I think advertising the decimal-based number when the everyday user will see the binary-based number comes across as deceiving. Although technically correct, it muddles it up a bit. I can see the manufacturers' challenge though.

        • Mike
          November 15, 2010 at 9:13 pm

          In theory, I agree with you. But the again obligation to inform is he who sells the drive. If you buy directly from the manufacturer you will always read a line like the following [from WD]

          "One gigabyte (GB) = one billion bytes. One terabyte (TB) = one trillion bytes. Total accessible capacity varies depending on operating environment."

          Apparently the one to blame is either yourself for not reading the warning, or the shop/assistant who didn't mention it.

          As for the manufacturers' challange, another example:
          NTFS format with Windows 7 will create a hidden 100MB partition "System-reserved" with crucial system files
          HFS+ format through Mac OS X (on Intel) will create a hidden 200MB partition "GPT" (part of the GUID Partition Table)

          you get the idea... right?

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