uses
 Printers;
type
 TMargins = record
  Left,
  ,
  Right,
  Bottom: Double
end;
procedure GetPrinterMargins(var Margins: TMargins);
var
 PixelsPerInch: TPoint;
 PhysPageSize: TPoint;
 OffsetStart: TPoint;
 PageRes: TPoint;
begin
 PixelsPerInch.y := GetDeviceCaps(Printer.Handle, LOGPIXELSY);
 PixelsPerInch.x := GetDeviceCaps(Printer.Handle, LOGPIXELSX);
 Escape(Printer.Handle, GETPHYSPAGESIZE, 0, nil, @PhysPageSize);
 Escape(Printer.Handle, GETPRINTINGOFFSET, 0, nil, @OffsetStart);
 PageRes.y := GetDeviceCaps(Printer.Handle, VERTRES);
 PageRes.x := GetDeviceCaps(Printer.Handle, HORZRES);
 //  Margin
 Margins. := OffsetStart.y / PixelsPerInch.y;
 // Left Margin
 Margins.Left := OffsetStart.x / PixelsPerInch.x;
 // Bottom Margin
 Margins.Bottom := ((PhysPageSize.y - PageRes.y) / PixelsPerInch.y) -
  (OffsetStart.y / PixelsPerInch.y);
 // Right Margin
 Margins.Right := ((PhysPageSize.x - PageRes.x) / PixelsPerInch.x) -
  (OffsetStart.x / PixelsPerInch.x);
end;
function InchToCm(Pixel: Single): Single;
// Convert inch to Centimeter
begin
 Result := Pixel * 2.54
end;
procedure TForm1.Button1Click(Sender: TObject);
var
 Margins: TMargins;
begin
 GetPrinterMargins(Margins);
 ShowMessage(Format('Margins: (Left: %1.3f, : %1.3f, Right: %1.3f, Bottom: %1.3f)',
 [InchToCm(Margins.Left),
  InchToCm(Margins.),
  InchToCm(Margins.Right),
  InchToCm(Margins.Bottom)]));
end;