All Delphi

When working with files from Delphi you might want to display the size of a file to the user in a Explorer-like format where the file size is not displayed in bytes – but the display depends on the size of the actual file.

To most users “45678123 b” is confusing – where “43.56 MB” is much more user friendly.

Format Byte Size to String

A custom Delphi function, FormatByteSize, converts a byte value into a string that represents the number expressed as a size value in bytes, kilobytes, megabytes, or gigabytes, depending on the size.

    //Format file byte size
    function FormatByteSize(const bytes: Longint): string;
    const
      B = 1; //byte
      KB = 1024 * B; //kilobyte
      MB = 1024 * KB; //megabyte
      GB = 1024 * MB; //gigabyte
    begin
      if bytes > GB then
        result := FormatFloat('#.## GB', bytes / GB)
      else
        if bytes > MB then
          result := FormatFloat('#.## MB', bytes / MB)
        else
          if bytes > KB then
            result := FormatFloat('#.## KB', bytes / KB)
          else
            result := FormatFloat('#.## bytes', bytes) ;
    end;