Why each time I reformat a drive, the capacity gets smaller and smaller?

[hajime]

Hi, I have noticed that over the 20+ years, each time I reformat a drive, be it under Windows or Mac OS, the capacity gets smaller and smaller? Is there a way to reclaim those lost spaces due to drive reformat?

 

[mi7chy]

Maybe some leftover hidden partitions taking up space. Reformat won't touch those. Have to zero out the partitions like Windows diskpart command line tool.

https://www.windowscentral.com/how-clean-and-format-storage-drive-using-diskpart-windows-10

Other than that, use SMART tool to see if your drive is degrading.

 

[hobowankenobi]

Or...are you just seeing the effects of the modernization of file systems? Over time, nearly every file system has reserved more and more space for restore functions, snapshots, etc.

If so, it is simply the cost of a modern operating system; nothing to be done about it in most cases.

 

[MacCheetah3]

It could be what @hobowankenobi pointed out as well as bad blocks/sectors.

Bad Sectors Explained: Why Hard Drives Get Bad Sectors and What You Can Do About It

A bad sector on a hard drive is simply a tiny cluster of storage space -- a sector -- of the hard drive that appears to be defective.

www.howtogeek.com