How to print postcards at home: double-sided, cut to size, ready to post

Home printers cannot feed a single postcard-sized piece of card reliably, so the trick is to print four postcards on one full sheet and cut them apart afterwards. A landscape A4 sheet divides neatly into four A6 postcards of 148 × 105 mm, which is the standard postcard size across most of Europe. A US Letter sheet gives four postcards of 5.5 × 4.25 in, which is inside the size range the US Postal Service treats as a postcard.

Side A of the sheet carries the four pictures. Side B carries the four message sides: a short caption line, space to write, a dividing line, address lines and a stamp box. The backs have to be mirrored left to right so that each message lands directly behind its own photo when the sheet turns over. Foldpic does this layout for you; if you build it yourself in another tool, mirroring the back is the step people miss.

Postcard weight matters more than anything else you choose. Ordinary 80 gsm copy paper is far too flimsy to survive a sorting machine and feels like a leaflet in the hand. Aim for 200–300 gsm matte card. 250 gsm is a good middle ground: stiff enough to post, thin enough for most home inkjets to feed through the rear or manual tray. Check your printer's manual for its maximum weight; many home models stop at around 250–300 gsm.

Choose card that prints on both sides. Glossy inkjet photo paper is usually coated on one face only, so the message side smears; double-sided matte card takes ink and a pen on both faces. Set the paper type to Card or Heavy in the print dialog.

Print the sheet landscape at 100% or Actual size, never Fit to page, otherwise the layout shrinks by a few per cent and the cut marks drift away from the edges of the pictures. Turn on two-sided printing and choose flip on short edge. That setting turns a landscape sheet so the back shares the same top edge as the front; with the other setting every message side comes out upside down.

If your printer has no automatic duplex, print side A first, let it dry for two or three minutes, then put the sheet back in the tray printed side down with the same edge leading, and print side B. Most printers mark the tray with a small icon showing which way up the paper goes; if in doubt, pencil an arrow on a test sheet and run it once. Hold the finished sheet up to a window: every message side should sit squarely behind its picture, the same way up.

You only need two cuts: once across and once down the middle, along the tick marks on the edges. Use a metal ruler and craft knife, or a paper trimmer for straight edges in under a minute.

Home duplex printing is rarely perfect; a 1 mm shift between the front and back is normal. Keep important things such as faces and text slightly away from the edges, and if you see a thin white sliver along one side after cutting, trim a millimetre off every edge of that postcard. It will still be well inside the size range postal services accept.

Four different postcards suit a trip: one view per card. With fewer designs, Foldpic repeats them to fill the sheet, so one design prints four identical postcards.

Write the message by hand after printing. Keep the right half of the back clear for the address and stamp.