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why is my sd card only 14.7 gb?

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 almacncheese 3rd November 2013, 05:40 AM Junior Member - OP Thanks Meter 0 Posts: 8 Join Date: Oct 2013 More Info > why is my sd card only 14.7 gb? So I bought a 16 GB SD card and I formatted it on my s4 now it's only 14.7 GB REPLY

Shrihari007
Senior Member
Thanks Meter 218
Posts: 422
Join Date: Apr 2012
Location: Hubli
Quote:
 Originally Posted by almacncheese So I bought a 16 GB SD card and I formatted it on my s4 now it's only 14.7 GB
Have you ever experienced that moment where you insert
your 16GB memory card into the camera only to discover
that this new, freshly formatted card is a nickel short of
15GB? Or a 32GB card turning to 29.8GB once installed?
Have you ever wondered where those GigaBytes are hiding?
The truth is that they are not hiding at all.
It has to do more with the way card companies (and hard
drive companies too) decide to annotate their products.
In English Kilo means one thousand (1000 1 = 1,000), a
Mega is a million (1,000 2 = 1,000,000) , a Giga is a billion
(1,000 3 = 1,000,000,000) and so on (Tera, Peta, Exa, Zetta &
Toyya). This system is called the SI units system .
In Computerish, however, the numbers are a bit different: A
Kilo means 1,024 1 = 1,024, a Mega is 1,024 2 = 1,048,576, a
Giga is 1024 3 = 1,073,741,824 and so on. This is called the
Binary units system.
So there is a difference in what Kilo, Mega and Giga means
and that difference is getting bigger the "stronger" the prefix
is.
For Kilo, the difference is only 2.3%, for Mega it is 4.6% and
for Giga it is 6.8% - see a pattern here?
Back to the memory cards.
Memory cards manufactures choose to use the SI system to
denote cards sizes. Our computers and card readers use
the binary system for size calculation and here is where the
missing Bytes are.
Of course, the card companies are covered, they do mention
this fact on their sites (in a small asterisk, or with hover text
that is revealed when you hover over a small asterisk). Here
are screen shots from three leading cards and hard drive
manufacturers, though they are not the only one to use that
practice:
Sandisk:
Lexar:
Seagate:
If you followed the math, you probably realized that the toll
this calculation method in taking gets bigger the bigger the
data units are. So while the toll on a 1GB memory card in
way smaller than on a 1 tera hard drive. Have a look at this
table to sum things up:
Size SI
units size
Binary
Size
Delta
(%)
Delta
(GB)
512 Mega 536870912 512000000 4.6 0.02
4 Giga 4294967296 4000000000 6.9 0.27
16 Giga 17179869184 16000000000 6.9 1.10
64 Giga 68719476736 64000000000 6.9 4.40
1 Tera 1,099,511,627,776 1,000,000,000,000 9.1 92.68
4 Tera 4,398,046,511,104 4,000,000,000,000 9.1 370.71
1 Peta 1,125,899,906,842,620 1,000,000,000,000,000 11.2 117253.43
Now What?
Now, I think it would be fair if we politely asked memory
card makes and hard drive makers to switch to binary so
they will be better aligned with the way we use them.
Quote:
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jazz995756
Senior Member
Thanks Meter 126
Posts: 407
Join Date: Jul 2012
Quote:
 Originally Posted by almacncheese So I bought a 16 GB SD card and I formatted it on my s4 now it's only 14.7 GB
There's always a disclaimer *formatted capacity less* so this is normal

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