64gb actual capacity

Manufactures measure using 1000 MB per GB, but the actual conversion is 1024 MB per GB.

They consider 1 KB to consist of 1000 bytes. A byte being 8 bits or 8 1's and 0's of actual information. As drives increase in size, this inaccurate form of measurement becomes more and more noticeable.

For example:

1GB is supposed to consist of 1,073,741,824 Bytes

a 1GB HDD consists of only 1,000,000,000 Bytes

1TB should consist of 1,099,511,627,776 Bytes

1TB HDD only contain 1,000,000,000,000 Bytes

That is 10% of the advertised space.

To calculate the actual space:

True size (64,000,000,000 Bytes) / Advertised size (68,719,476,736 Bytes) = .931

.931 * 64GB = 59.6GB

Now subtract about 2GB for the OS.

As for your 16GB iPhone 5:

True size (16,000,000,000 Bytes) / Advertised size (17,179,869,184 Bytes) = .931

.931 * 16GB = 14.9GB

Now subtract about 2GB for the OS.

I understand the math on that, but my brand new 64GB iPad Air 2 has a stated capacity of 55.5 with an available of 51.4 (out of the box) Sounds like the actual capacity should be closer to 59GB and then available capacity should be a few GB less due to the OS and apps that ship with it. So, I'm feeling like I'm short about 4 GB, or am I missing something?

Thanks!

You're welcome.

I don't disagree.