Is there a way in VB6 where I could get the file's "Size on disk" (not the size).
I cannot achieve this by using the FileSystemObject's size property which only returns the file's size.

If this cannot be done, maybe a help on how to achieve these other options will do:
1. A way to capture what is displayed in the properties dialog box (right click a file then properties)
2. A command in the command prompt which can somehow retrieve "Size on disk"?

[Please refer to the attached file if you can't understand what I mean]

Any help will be very much appreciated. Thanks in advance.

Attachments sizeondisk.jpg 60.39 KB
6 Years
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Last Post by cubekid

The native GetAttr function will return some of the information you are looking for (read only, archive, hidden, and system) while the GetFileAttributes API will return a bit more information as will the GetFileAttributesEx API. Then there is the GetFileInformationByHandle API but for finding the size on disk, I cannot remember right off the top of my head.

Good Luck


Nice tip but it doesn't solve the problem. Thanks.

Anyone, please help...


Okay, I remember now. The size on disk is calculated by using the GetDiskFreeSpace API that returns bytes per sector as a sector is the smallest portion of addressable space on a disk. Meaning, if a disk has 4kb per sector and you save a 1kb file, it will take up an entire sector (4kb). On the other hand if you save a 5kb file, it will take up 2 sectors or 8kb...

Good Luck


From what I know, disks have different bytes per sector.
Could you give the function which can return the value of bytes per sector of a disk?
Or maybe the formula on how to achieve this.

I researched about the GetDiskFreeSpaceEx API from Microsoft.

In the example given, three return values have been produced:
1. Available Space
2. Total Space
3. Free Space



Hello vb5prgrmr!

I have researched on the GetDiskFreeSpace API and yes it does answer my questions.
Actually, the one in MSDN is a help for Visual FoxPro and not for VB.
I'm not sure if I have installed MSDN correctly.

Anyways, this is how I solved it: (This is just the step-by-step procedure to solve the problem. The programmatic solution will be shown on my next post)
1. I need to figure out the ff. disk properties:
a. Bytes Per Cluster
b. Sectors Per Cluster
c. Bytes Per Sector

The GetDiskFreeSpace API can return "Sectors Per Cluster" and "Bytes Per Sector".

2. To get Bytes Per Cluster:
BytesPerCluster = SectorsPerCluster * BytesPerSector
ex. 8[SPC] * 512[BPS] = 4096[BPC]

3. By using the scrrun.dll, you can get the file size of the file to evaluate.
example.txt = 364 bytes

4. Divide the file size with Bytes Per Cluster.
FileSize = FileSize / BytesPerCluster
ex. 364 / 4096 = 0.0888671875

5. If filesize is in fraction (or has decimal), make it a whole no. then add 1 else retain the value.
ex. since(0.0888671875) make filesize = 1

6. Compute for size on disk
SizeOnDisk = fileSizeWholeNo * BytesPerCluster
ex. 1 * 4096 = 4096

Referring to my attached file, example.txt's property is:
size = 364 bytes
size on disk = 4096 bytes

I also tested this in Fat32 and the formula works.

Edited by cubekid: wrong content

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