Kod:
procedure TForm1.Button1Click(Sender: TObject);
var
  srFileSR: TSearchRec;
  sFileName, sFileSize: string;
begin
  sFileName := 'c:\deneme.zip';
  FindFirst(sFileName,faAnyFile,srFileSR);
  sFileSize := IntToStr(srFileSR.Size);
  Showmessage(sFileSize);
end;