GB vs GiB, MB vs MiB .. 1000 vs 1024


are there any settings how I can specify the value (1000 or 1024) for calculating the "Size"?

DO shows the wrong (international standard!) values (as Explorer).

Correct - IEC / BIPM / IEEE standard:
1 GB = 1000 MB (SI, Decimal)
1 GiB = 1024 MiB (Binary)

5578 Bytes for a file are currently in DO 5,44 KB.
5578 Bytes = 5,44 KiB
5578 Bytes = 5,58 KB (rounded - btw. good would be always a round-up? is there a standard defined for rounding?)

or better the German version (better tables (and better written and explained as the English version))

I also want to see e.g. "934 Bytes" - and not "934 bytes" (which DO currently displays) (upper case written "B") in the column "size".


This is very pedantic. 99.99% of people see 1KB as 1024 bytes, not 1000 bytes and I don't really think it's worth a configuration option for the one or two people who would care about this :slight_smile:

Those new GiB (etc.) suffixes only add to the confusion because they're revisionist about what the GB (etc.) suffixes mean.

If they had brought in new suffixes to mean multiples of 1000 then I might support the idea, but redefining what the old suffixes mean while bringing in new suffixes which mean what the old ones used to is downright stupid.

It's been multiples of 1024 for decades. It's too late to change the meaning of the old suffixes.

That is not true.

For external storages (hard drive, DVD's, etc.) always 1000 was used - I know this since the 80's - we also had learned it in our school. It's also written on the link above (much better explained on the German version).

There was or is also another system (we have learned in the 80's and I've read it anywhere too in the www): Lower-case written suffixes means 1024, upper-case means 1000. 1 gb = 1024 mb, 1 GB = 1000 MB.


DOPUS should allow the user if he want's to use the international standard or not (or both at the same time). Add an option or additional values for the status bar, etc.

Todays you also should use Unicode and don't say ASCII has been used for decades - it's too late. :wink:

New international standards arrive - and - in this case - have been ALWAYS used for external storages.

Best regards,

PS: I also do not like the new suffixes (new for me) - I'm also old-school - but I know that 1024 is not correct when I buy a hard disc or whatever - and it's good to have an international standard. GiB sounds better then gb - however ...

PSS: And currently I know when I select all files on my hard disc that DOPUS shows me 1024 ... and I have to re-calc it to 1000 to buy the correct hard disc for a backup :wink:

It's only been true for HDDs if you're reading the label on the physical HDD. (And that's just so that HDD makers can make you think their drives have more space. :slight_smile:) Operating systems, as far as I know, have always reported multiples of 1024.

This isn't an international standard like Unicode, either. It serves no purpose except to confuse and it's used by virtually no-one.

(Edit: Yes, SI units are an international standard, obviously, but they're only standard for use outside of computers. The revisionist suffixes are certainly not an international standard. Maybe Opus could report things with different suffixes but then we'd have to make up our own.)

(Edit 2: I should clarify that by standard I mean "something typical people actually use." I realise that some standards bodies, who are international, have endorsed the new prefixes. To me that doesn't make them standard, though, any more than it makes Microsoft's "Open XML" office format an industry standard. :slight_smile: )

(Edit 3: Of course, the old standard also causes confusion and if we had a time machine I'm sure we'd go back to the 1960s and stop it. But rather than resolve that confusion the new "standard" adds to it. Until about 1999 almost all software reported MB, GB etc. meaning the 1024 versions. That is still the case now but people are encouraging some software to switch to the 1000 versions while using the exact same suffixes as before. Utter madness. It's unfortunate that the SI suffixes were abused in this way but you can't resolve the ambiguity of the old suffixes by changing their meaning to the even less common version in some software but not all. MiB and GiB are unambiguous (and not understood by many people), sure, but the people advocating their use didn't think things through properly regarding the MB and GB suffixes, making the overall proposal a joke, IMO.)

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haha pedantic = geekish ? :stuck_out_tongue:

Here's a handy button that toggles between the size(auto) and size(bytes) columns, for when you need to see an exact byte count that isn't subject to the 1000 vs 1024 stuff:


The same values can be shown in the status bar, although there isn't a quick way to toggle the status bar between one format and the other like the button does for the file display.

Or you could use the Size On Disk columns, which account for cluster sizes on the drive the files are on:

Set COLUMNSTOGGLE=disksizeauto(1) Set COLUMNSTOGGLE=disksize(1)

Of course, even if you use the Size On Disk columns, the total still won't accord for the size of the formatting information which will use up some space on the backup HDD, nor any differences in cluster size that it has compared to the local disk, (nor bad sectors, etc.) so it seems a moot point, TBH. Without going into ridiculous detail, you always have to (over-)estimate the size required when buying a HDD to fit particular data.

Searching for this particular question didn't yield many results, here's another, older thread too: Option to use Correct SI Binary Prefixes for Quantities

So, although this is an old thing bumped, I'd personally like to see an option to view the sizes with the correct notation, even though I realise it is basically cosmetic.

You could have an option to view them in actual base 10 sizes too, because bear in mind Mac OS X now does this since Snow Leopard - it does NOT report sizes we all think of, it uses the sizes hard drive manufacturers have all been using.

So, as much as people think it doesn't matter, there is real confusion to be had, especially when using both Operating Systems.

I'd like to see an option to calculate it as Mac OS X does, (although I personally wouldn't use that), a way to calculate it as currently done, but with the correct notation (KiB, MiB, GiB, TiB.. etc) and a way to use the calculation we're used to, but with the old, incorrect notation. The last probably being the default to reduce complaints. I'd personally use the second option. I just prefer it to look right, I suppose.

Don´t know, if it helps, but there is already some option (-> settings -> preferences -> miscellaneous -> advanced -> file_size_units), which you can change to "decimal unit / decimal prefix".

Oh yeah. It works. It's all there. Problem solved!

Sorry to bump this old topic, but I have to write something... :smiley:

That is definetely not true.

A 3,5'' floppy disk was specified with 1,44 MB, but this was definetely not 1,44 MiB. It was never possible to put a 1,4 MB file on a 1,44 MB floppy...
According to wikipedia the size was 1440 KiB = 1,4 MiB. So it was a combination of decimal and binary prefix.

Also some SD-Card manufacturer like Sandisk uses the decimal system.
e.g. Number of pictures that can be stored on a memory device
(In this case I know it for sure, because I was in contact with Sandisc regarding this topic)

I have an USB Stick that is specified with 32 GB. Windows says 29,2 GB.
29,2 GiB = 31,4 GB - So 0,6 GB are missing, but I guess the 32 GB is rounded up.

Another USB Stick with 4 GB has 3,73 "GB" according to Windows. 3,73 GiB = 4 GB

A DVD is specified with 4,7 GB. Windows says 4,37 GB. 4,37 GiB = 4,7 GB

So for nearly all data storage media the size is specified with the decimal system.

And Windows is now the only operating system which uses the decimal prefixes for binary size.
Linux shows binary prefixes and Mac OS uses the decimal system (according to Binary prefix - Wikipedia)

I changed in Opus the setting to binary prefixes. It took me a while to find this setting via forum search. Why do you not put this setting a little bit more obvious into another area?

You couldn’t put a 1.44MB file on a 1.44MB floppy because of formatting overheads.

This thread is 13 years old and it’s a little tedious to necro it like this.

The option is already there for people who want it and you can search Preferences, the forum, or the manual to find it. Most people just want the platform standard way of representing file sizes. This is a niche option.