New 1TB MyBook with only 930 GB Storage Free

Hello all, I am hoping someone has some insight into this:

I just purchased a new 1TB MyBook from Best Buy.  I plugged it into my laptop running a

64 bit Windows 7 Pro.  The MyBook only has 930 Gb free for some reason… I don’t understand why its not closer to 1TB? 

I find this frustrating and am hoping someone can offer some insight as to why 70 GB’s cant be accounted for?



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Why would it only reach 930 when the box says 1tb?

Hi friend;

I can’t believe no ones addressed this for you yet.

It’s because the drive is pre-formatted.

It it were unformatted it would read a bit over 1,090GB.


PS There was actually a suit(s) brought against drive manufacturers a few years ago for that exact reason (truth in advertizing).

Not sure what the outcome was…

I have a 1.5 terabyte and all it shows is 1.3 …

well, actually:

Determining drive capacity can be confusing at times because of the different measurement standards that are often used. When dealing with  Windows  and  Mac  based systems, you will commonly see both decimal measurements and binary measurements of a drive’s capacity. In either case, a drive’s capacity is measured by using the total number of bytes available on the drive. As long as the drive displays the correct number of bytes (approximate), you are getting the drive’s full capacity.

Note: Mac recently published an article titled, " How Mac OS X reports drive capacity" detailing how it reads drive sizes. This article includes some changes made in Mac OS X v10.6 Snow Leopard in how the OS will report drive sizes.

Decimal vs. Binary:
For simplicity and consistency, hard drive manufacturers define a megabyte as 1,000,000 bytes and a gigabyte as 1,000,000,000 bytes. This is a decimal (base 10) measurement and is the industry standard. However, certain system BIOSs, FDISK and Windows define a megabyte as 1,048,576 bytes and a gigabyte as 1,073,741,824 bytes. Mac systems also use these values. These are binary (base 2) measurements.

To Determine Decimal Capacity:
A decimal capacity is determined by dividing the total number of bytes, by the number of bytes per gigabyte (1,000,000,000 using base 10). 

To Determine Binary Capacity:
A binary capacity is determined by dividing the total number of bytes, by the number of bytes per gigabyte (1,073,741,824 using base 2).

This is why different utilities will report different capacities for the same drive. The number of bytes is the same, but a different number of bytes is used to make a megabyte and a gigabyte. This is similar to the difference between 0 degrees Celsius and 32 degrees Fahrenheit. It is the same temperature, but will be reported differently depending on the scale you are using.

Important: If you are dealing with drive sizes smaller than the  Approximate Binary Capacity  of your  Drive Size , then you may be dealing with either a BIOS limitation, or a Windows drive size limitation. Answer ID 936: Operating System and BIOS limitations - 137GB, 32GB, 8.4GB: Answer ID 936: Operating System and BIOS limitations. For more information, please see links below. 

Operating system & BIOS limitations:

Summary of drive capacity issues in window: