How Big is that File – in English?

Humans and computers sometimes just don’t get along. Take file sizes, for example. What a human being would call one gigabyte, a computer would call 1073741824 bytes. How do you translate one into the other? Pull up a chair.

The following handy function takes a number of bytes and translates it into a readable “human” string. Here’s the code:

Public Function ConvertBytes(ByVal Bytes As Long) As String
    ' Converts bytes into a readable "1.44 MB", etc. string
    If Bytes >= 1073741824 Then
        Return Format(Bytes / 1024 / 1024 / 1024, "#0.00") _
            & " GB"
    ElseIf Bytes >= 1048576 Then
        Return Format(Bytes / 1024 / 1024, "#0.00") & " MB"
    ElseIf Bytes >= 1024 Then
        Return Format(Bytes / 1024, "#0.00") & " KB"
    ElseIf Bytes > 0 And Bytes < 1024 Then
        Return Fix(Bytes) & " Bytes"
    Else
        Return "0 Bytes"
    End If
End Function

Here’s an example of the function in use. Here, the length of my file is 3027676 bytes—and the ConvertBytes function returns “2.89MB”. Perfect:

Dim objInfo As New System.IO.FileInfo("c:\myfile.bmp")
MessageBox.Show("File is " & ConvertBytes(objInfo.Length))