It may "make sense" but that's actually a false equivalence. The raw disk space for a 3.5" high-density floppy disk for IBM PCs is 512 bytes per sector * 18 sectors per track * 80 tracks per side * 2 sides = 1,474,560 bytes. It is 1.47 MB or 1.40 MiB neither of which is 1440 KB or KiB. The 1440 number comes from Microsoft's FAT12 filesystem. That was the space that's left for files outside the allocation table.

Sectors per track or tracks per side is subject to change. Moreover a different filesystem may have non-linear growth of the MFT/superblock that'll have a different overhead.

https://en.wikipedia.org/wiki/List_of_floppy_disk_formats

Not my downvote, good chart actually.

It is worse of a downer when there is a complete failure to make further sense like that, but I'll try to do something.

Of course one chart does not an expert make, I don't understand half of it but at least I worked with 3.5 floppies since they first came out.

3.5 floppies are "soft sectored" media and usually the drives were capable of handling non-standard arrangements too. What made non-standard numbers of sectors uncommon was it would require software most people were not using. DOS and Windows simply prepared virgin magnetic media with 2880 sectors, or reformatted them that way and that was about it.

PC's were already popular when 3.5 size came out, and most of the time they were not virgin magnetic media, they were purchased pre-formatted with 2880 sectors (of 512 bytes per sector) already on the entire floppy, of which fewer sectors were available for user data because a number of sectors are used up by the FAT filesystem overhead.

On the chart you see the 1440kb designation since each sector is considered 1/2 "kilobyte".

512 bytes is pretty close to half a kilobyte ain't it?

(The oddball 1680kb and 1720kb were slightly higher-density sectors, with more of them squeezed into the same size media, most people couldn't easily copy them without using an alternative to DOS or Windows. Sometimes used for games or installation media.)

With Windows when partitioning your drive if you want a 64 GB volume you would likely choose 64000 MB in either the GUI or Diskpart. Each of these GB is exactly 2880000 sectors for some reason ;)

But that's the size of the whole physical partition whether it contains only zeros or a file system. Then when you format it the NTFS filesystem has its own overhead.