FormatBytes() - How big is that?

A handy function for formatting bytes, such as disk or file sizes.

1,024 bytes = 1 KB 1,048,576 bytes = 1 MB 1,073,741,824 bytes = 1 GB 1,099,511,627,776 bytes = 1 TB 1,125,899,906,842,620 bytes = 1 PB 1,152,921,504,606,850,000 bytes = 1 EB 1,180,591,620,717,410,000,000 bytes = 1 ZB

Kilobyte Megabyte Gigabyte Terabyte Petabyte Exabyte Zetabyte

To format a byte count as a string, here’s a quick little routine to do the trick.

   1:      Public Function FormatBytes(ByVal nBytes As Double, Optional ByVal szFormatString As String = "###,###,###,##0") As String

   2:   

   3:          Dim POSTFIXES() As String = {"Bytes", "KB", "MB", "GB", "TB", "PB", "EB", "ZB", "YB"}

   4:          For n As Integer = POSTFIXES.Length - 1 To 0 Step -1

   5:              Dim nPow As Double = Math.Pow(1024, n)

   6:              If nBytes >= nPow Then

   7:                  nBytes /= nPow

   8:                  Return nBytes.ToString(szFormatString) & " " & POSTFIXES(n)

   9:              End If

  10:          Next

  11:          Return nBytes.ToString(szFormatString) & " Bytes"

  12:   

  13:      End Function