Format of Sandisk Ultra USB3.0

I have 2 SanDisk ultra 128 GB thumb drives.
1st is original format FAT 32 with 2 partitions 1 is 31MB unallocated the other is 117.3 GB Healthy
Primary. There is a quick start guide on it.

2nd I formated I can selct from exFAT or NTFS format max of 115GB. How can I format to original size?
I am using windows 10.


Hi @BigAl4638,

Please be informed that what you are observing is the difference in the definition of one Gigabyte by operating systems versus product manufacturers. Operating systems use a binary system which will present a lower number of GB than the decimal-based system used by manufacturers to define the capacity of products. This is due to the binary system representing a GB as a higher number of actual bytes.

For example: Operating systems define a 1GB as 1,073,741,824 Bytes. We define 1GB as 1,000,000,000 bytes.

To understand this difference in definition better, you may refer to the following articles from our online Knowledge base:

If further assistance is needed, please open a case with our support team at the following:

Hi Keerti_01,
I understand GB etc. What I don’t understand is why capacity on 2 identical drives is different. The original format is FAT32 has 126,164,697,544 bytes. Fat32 is not an option on Windows 10. The one I reformatted as NTFS has 115GB/124,216,406,016 bytes. How can I recover the lost space? Thanks, Al

Here is what I see

You can completely clear and reset the partitions and master boot record by using the diskpart utility included in every Windows OS system.

The diskpart command interpreter helps you manage your computer’s drives.

Back up all your data first before attempting this

  • Open Command Prompt (cmd) in administrator mode
  • Type in diskpart
  • Type in list disk
  • Select the option with the USB you want to reset
  • Type in clean
  • Type in convert mbr
  • Type in create partition primary
  • Then format the USB to your preferred settings

    What the commands do:
  • The clean command removes any and all partition or volume formatting from the disk with focus
  • The convert mbr command converts an empty basic disk with the GUID Partition Table (GPT) partition style into a basic disk with the master boot record (MBR) partition style
  • The create partition primary creates a new primary partition
  • Format it to be able to use it


Brnkm, Thanks for the instructions.
Unforturnately, the result was the same! the Windows 10 format olny gives me a size of 115GB to use. Some how it came with 117GB but I cannot format it back to 117GB.
Thanks, for your help!