# How much space is actually in a 1TB micro SD card ?



## TheSpearGuy (Oct 6, 2019)

Title says it all.


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## Jokey_Carrot (Oct 6, 2019)

If my maths is right some where around 930 gigabytes.


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## bitjacker (Oct 7, 2019)

1 Tb.


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## Hayato213 (Oct 7, 2019)

931GB, base off 931GB of space from a 1TB Hard Drive calculation.


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## piratesephiroth (Oct 7, 2019)

You want to convert from Gigabytes to Gibibytes


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## FAST6191 (Oct 7, 2019)

It might vary.

In general storage discussions the hard drive/storage companies companies seemed to favour powers of 10 or more commonly multiples of 1000 for their multiplier conventions (as opposed to the 1024 multiple most sensible people would use for storage), which really started to show what goes when you get up into the terabytes.

This leads to a drop that way.

You do also have the usual space set aside for the file system and whatever else it needs there.

Beyond that for flash memory then it varies further, and varies between vendors. In case you were unaware flash memory is not easy to make and most have lots and lots of bad sectors inherent to it (50% of total theoretical capacity is probably a stunningly good outcome for a batch) but that is OK as you just steer around the bad stuff and whatever remains is your chip and you size accordingly. I don't know if SDXC has tried to reign it in but some vendors just used a minimum size limit, some vendors include the spaces they set aside to allocate, sometimes if lower capacities were selling more the vendors would chop bits off or give you more than you thought you were getting (if you had 512 gigs and they had some chips that comfortably did 600 you might get 600 as 600 is not enough to go for 1024, or even 768).


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## Pleng (Oct 7, 2019)

> vendors would chop bits off or give you more than you thought you were getting (if you had 512 gigs and they had some chips that comfortably did 600 you might get 600 as 600 is not enough to go for 1024, or even 768).



Did this really happen? I've never heard of anybody getting *more* than the stated amount of storage. In fact I've never heard of anyone getting anything other than the stated size.


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## ghjfdtg (Oct 7, 2019)

You get exactly 1 Terrabyte (in power of 10 1000000000000 bytes). In Gibibytes what most operating systems show in reality (power of 2) you get ~931.322.


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## FAST6191 (Oct 7, 2019)

> Did this really happen? I've never heard of anybody getting *more* than the stated amount of storage. In fact I've never heard of anyone getting anything other than the stated size.



It has been a while but I got a bunch of nice USBs to resell once and gave them all a token format (same setup), and some wanted some files on them before I sold them to them. End results were in the several hundreds of megs on sub 100 gig sizes.

There have also been people unlocking their memory cards at points (these days SD cards have been seen to have full power ARM processors, which amuses me when I think about them in flash carts) and not all vendors of them locked them down (as mentioned some did gate it off and call the rest dead sector replacement space) with the more cheapo ones being inclined to give you the higher sizes.

Bunnie's 30C3 talk "The Exploration and Exploitation of an SD Memory Card" is a fairly nice intro to some of the more exotic things if you wanted that


His blog post on the talk if you don't have time for a video https://www.bunniestudios.com/blog/?p=3554

and while it is not especially relevant here I will also link https://www.bunniestudios.com/blog/?page_id=1022 mainly because it is interesting.


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## TheSpearGuy (Oct 7, 2019)

Big tahnks for all your replies 
I really appreciate it


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## godreborn (Oct 7, 2019)

what I wish is that the switch could remember which card held which games instead of having the entire list no matter which card is used.  I'm going to be using a couple 128GB cards for my games after luigi mansion 3's out.  I only have 5.9GBs of space left.


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## The Real Jdbye (Oct 7, 2019)

@Pleng I think he might be referring to the oddball 200 and 400GB sizes that were released, although I always assumed there were actual hardware changes to make those sizes possible, and simply not higher binned 128/256 GB cards that were capable of (had enough spare good sectors) to fit 200 and 400GB of data. I don't think there are actually that many extra sectors set apart. On a SSD you typically see 120GB, 240GB etc sizes with 8, 16 etc. set apart for spare sectors, which is not actually that much. SD cards I always thought had no spare sectors on them as they are manufactured to cost, and you always see them sold with the "full" capacity of 128/256 etc rather than 120/240 etc. But maybe I am wrong there.


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## FAST6191 (Oct 7, 2019)

I am aware of the non power of 2 sized cards/chips (they might have even been in response to some of these) and was not talking about them. This was actual higher sizes than the size they were sold as.


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