The short version
- The standard postcard is 6 × 4 inches, which is 1800 × 1200 pixels at 300 dpi.
- A postcard has a picture side, which should carry one message, and an address side, which must leave clear space for the address, stamp and postal markings.
- Larger mailers such as 5 × 7 and 6 × 9 inches give more room but may cost more to post, so check your postal service's size rules first.
- A marketing postcard works best with one offer, one reason to act now and one way to respond.
- Before printing, extend the picture side into the bleed and keep every word inside a safe margin.
On this page
For postcard design, start with the classic 6 × 4 inch card, which is 1800 × 1200 pixels at 300 dpi. Give the picture side one image or colour field and a single short line, and keep the address side plain: your message on the left, the address and stamp on the right, and a clear strip along the bottom for postal markings. Whether it is a holiday card, a thank you for customers or a direct mail offer, that split is what makes a postcard work.
Postcard sizes in inches and pixels
Pixels at 300 dpi
Typical use
Pixels at 300 dpi
Typical use
Pixels at 300 dpi
Typical use
Inches
Pixels at 300 dpi
Typical use
6 × 4 in
1800 × 1200
A6
1748 × 1240
7 × 5 in
2100 × 1500
9 × 6 in
2700 × 1800
Designing the picture side
The picture side is seen first and for the shortest time, usually on the way from the doormat to the kitchen. Treat it like a poster in miniature: one image or colour field, one line of type, and nothing that needs reading closely. Landscape is traditional, but a portrait picture side stands out in a pile precisely because most cards aren't.
Landscape, one warm line, colour to every edge. A thank you card for customers.
Portrait, for a moving announcement. The headline is readable from across the hallway.
Colour does a lot of the work at this size. A deep, rich ground reads as quality in the hand; pale washes can look unfinished once printed. If you use a gradient, our guide to printing gradients explains how to keep it smooth on paper.
Laying out the address side
The address side belongs partly to the post office. Their machines need to find the address and stamp without help, so keep the right half quiet and the background white or very pale. Postal rules vary by country, so check yours; the layout below suits most of them.
What goes there
Where
What goes there
What goes there
Where
What goes there
Postcard mailers that people keep
A marketing postcard competes with bills and takeaway menus. The ones that get pinned to the fridge do three things: they make one offer, they give a reason to act soon, and they make responding easy. Here are ideas that suit different businesses:
- A local café: "Your first flat white is on us" with a QR code and a date the offer ends.
- An estate agent: "Just sold on your street" with the address and a line inviting a free valuation.
- A salon: a seasonal colour menu on the back and "Book before 30 April" on the front.
- A shop reopening: a portrait card with "Doors open Saturday" and a small map.
- An event: the date in large type on the picture side and the full details on the back.
Every one of those ideas leads with the reader's benefit, not the business name. The logo can sit small on the address side; people will turn the card over if the front gives them a reason. Agents sending cards and leaflets to a whole street will find more examples in real estate flyer design.
Avoid
- Three offers and no deadline
- Small type over a busy photo
- Your logo larger than the headline
- A web address with no reason to visit
Do
- One offer with a clear end date
- Short words on a calm background
- A headline the size of the card allows
- "Scan to book" beside a large QR code
Personal details lift a mailer, and they are where a design tool earns its keep. Gradiently's bulk create (Pro) takes one postcard page plus a CSV of names, streets or offer codes, connects each column to the text, and lets you review every version before creating the pages. The spreadsheet stays in your browser. For sending out the same offer by email too, see email header design.
Getting the print file right
- 1
Design both sides at the trim size
1800 × 1200 pixels for a 6 × 4 card. Keep the two sides in one file as two pages.
- 2
Add bleed to the picture side
Extend colour 0.125 in or 3 mm past each edge. Print bleed and safe margins shows how.
- 3
Keep text well inside the edge
Keep words at least 3 to 5 mm, roughly 0.125 to 0.2 in, inside the trim, and more for anything important.
- 4
Check every image at 300 ppi
A photo needs to be at least 1800 pixels wide to fill a 6 inch card sharply. See resolution for printing.
- 5
Export a print PDF
Gradiently Pro exports a print PDF with bleed and crop marks, which is what most printers ask for.
Questions people ask
What size is a postcard in pixels?
A standard 6 × 4 inch postcard is 1800 × 1200 pixels at 300 dpi. A 7 × 5 inch card is 2100 × 1500.
What is the standard postcard size in the UK?
A6, which is 148 × 105 mm, or about 1748 × 1240 pixels at 300 dpi.
What goes on the back of a postcard?
A message on the left, the address on the right, the stamp in the top right corner and a clear strip along the bottom for postal barcodes.
How do I make a postcard mailer effective?
Make one offer, give it a deadline and make responding easy, for example with a large QR code labelled with what it does.
Does a postcard need bleed?
Yes, if colour runs to the edge. Add 0.125 inch or 3 mm on every side, or whatever your printer specifies.
Written by Gradiently
The team behind Gradiently, a design tool built around Marks: living gradients that make everything you design look like yours.
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