This algorithm shows a converting hexadecimal value to the decimal value.
function HexToDec(Str: string): Integer; var i, M: Integer; begin Result:=0; M:=1; Str:=AnsiUpperCase(Str); for i:=Length(Str) downto 1 do begin case Str[i] of '1'..'9': Result:=Result+(Ord(Str[i])-Ord('0'))*M; 'A'..'F': Result:=Result+(Ord(Str[i])-Ord('A')+10)*M; end; M:=M shl 4; end; end; procedure TForm1.Button1Click(Sender: TObject); begin if Edit1.Text<>'' then Label2.Caption:=IntToStr(HexToDec(Edit1.Text)); end;