Retrieves the size of a file.

Size := FileGetSize(Filename, Units)



Type: String

The name of the target file, which is assumed to be in A_WorkingDir if an absolute path isn't specified. If omitted, the current file of the innermost enclosing File-Loop will be used instead.


Type: String

If present, this parameter causes the result to be returned in units other than bytes:
K = kilobytes
M = megabytes

Return Value

Type: Integer

This function returns the size of the specified file (rounded down to the nearest whole number).

Error Handling

An exception is thrown on failure.

A_LastError is set to the result of the operating system's GetLastError() function.


Files of any size are supported, even those over 4 gigabytes, and even if Units is bytes.

If the target file is a directory, the size will be reported as whatever the OS believes it to be (probably zero in all cases).

To calculate the size of folder, including all its files, follow this example:

FolderSize := 0
WhichFolder := DirSelect()  ; Ask the user to pick a folder.
Loop Files, WhichFolder "\*.*", "R"
    FolderSize += A_LoopFileSize
MsgBox "Size of " WhichFolder " is " FolderSize " bytes."


FileGetAttrib, FileSetAttrib, FileGetTime, FileSetTime, FileGetVersion, File-loop



Size := FileGetSize("C:\My Documents\test.doc")  ; Retrieve the size in bytes.
Size := FileGetSize("C:\My Documents\test.doc", "K")  ; Retrieve the size in Kbytes.