Find the difference between Size and Size on disk

When we right click on a file or a folder to see its properties and size, we see two different options saying “Size” and “Size on disk” having different values most of the time. The difference between “Size” and the “Size on disk” of a file has always confused me. I kept wondering “How can a file possess different size?”

No doubt you are reading this post because you also want to know the actual difference. So let’s find out the difference between “Size” and “Size on disk”.

•    “Size” is the actual size of the file or the folder in bytes.

•    “Size on Disk” means the size that is being taken up on the disk. We know that disk constitutes of Tracks and Sectors. So size on disk is the space of all those sectors in which the file is saved. Example, let’s say that the sector size is 512 bytes and the size of file is 600 bytes then the size on disk would be 1024 bytes because it is actually using two sectors.

That means usually the size on disk is always greater than the actual size.

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