Seagate 400 GB external HDD shows only 372 GB?

[yexusbeliever]

I have a situation.

I bought a Seagate 400GB external HDD. But once I plug and play, I only see the max is 372 GB. Almost 30 GB lost. Can someone enlight me on this? Why is it like this? And how will I get it to be max at 400 GB?

 

[TheMajor]

It is normal. HDD manufacturers use the decimal system (1000KB=1GB); operating systems use the binary system (1024KB=1GB).

 

[talldude123]

Check the 137GB sticky on this forum. Search for it.

 

[Nitestick]

yeah it's all just to do with hdd manufacturers being sneaky. they define a gigabyte as being 1,000,000,000 bytes where as far as a computer is concerned a gigabyte is 1024x1024x1024 bytes (1024 being 2^10, a binary number). if you calculate 400,000,000,000 divide by the total of 1024x1024 you will get the number of gigabytes your hdd is reporting.

 

[yexusbeliever]

I feel almost as I have been tricked.

It would have been much easier for them to just say that it is 372GB HDD.

I guess since it looks good to keep, I will keep it. But that is bad marketing for them to say on the cover to be 400GB and only get 372GB.

 

[Nitestick]

it's tricky but technically they're not lying, they're exploiting obscure facts. they use the symbol GB which technically is in multiples of 1000 the actual unit for binary numbers has an "i" in between e.g. GiB. that's how they get away with it.

 

[Meithan]

For the rule of thumb, actual storage capacity is 93% of the advertised capacity, when the numbers are in GB. So 400GB * 93% = 372GB. There's a 7% missing due to the aforementioned difference in nomenclature.

This table will give you the actual size multiplier based on the unit used:

KB -> 97.7%
MB -> 95.4%
GB -> 93.1%
TB -> 91.0%