How to Design a Direct Mail Postcard (Both Sides)
Most mail gets sorted over a bin. The whole decision takes about two seconds, standing in a hallway with a stack in one hand — and your postcard starts that moment face-down, because postcards come out of the mailbox address-side up.
That single fact decides most of a direct mail postcard design, and almost nobody designs for it. They make a beautiful front, treat the back as the boring admin side, and mail a piece whose first impression is a blank white rectangle with a name on it.
A postcard isn't a small flyer. A flyer gets picked up by someone who already chose to look. A postcard has to survive a sort it never asked for, on the side you didn't design.
Your postcard arrives face-down, so the back is the front
Open your own mailbox and look. The address side is what you see first, every time. If that side is white space, a logo, and a mailing address, you've spent your whole budget on the side that gets seen after the keep-or-bin decision.
So the rule is blunt: the address side has to earn the flip. Not with the full pitch — there's no room, and the postal service wants a lot of that space empty — but with one line big enough to read at arm's length while the piece is moving.
For a window cleaner, that line isn't "Fairview Window Cleaning, established 2019." It's "Your windows, done Thursday. $49." One promise, one number, at 30–40pt.
Two sides, two jobs
Split the work instead of repeating yourself. The same headline printed twice on both sides is a wasted side, and I see it constantly.
Address side (seen first): one hook line, the offer number, your name small. Everything else on this side belongs to the post office.
Picture side (seen second, if you earned it): the proof and the ask. A real photo of the actual result, three lines of what they get, the price, the phone number, the code, the expiry.
The flip is the conversion event. The address side sells the flip; the picture side sells the job.
The address block that kills layouts
This is where most first-time postcards get bounced back by the printer, so it's worth being precise about what you can't touch.
On the address side, the postal service needs the bottom band clear across the full width — plan on roughly 5/8 inch (16mm) of dead space along the bottom edge with nothing in it, no background colour, no thin brand rule sneaking through. That strip is where the routing barcode gets sprayed, and a graphic in it means either a rejected batch or a barcode printed on top of your design.
You also need a clean rectangle for the address itself, typically the right half of that side, plus a stamp or indicia box in the top-right corner about 1.5 inches square. On a 6×9 card that leaves a genuinely usable left column — around 4 inches wide — for your hook line. On a 4×6 card it leaves a strip, which is why 6×9 is worth the extra postage if your offer needs more than five words.
Two things save you here. Ask your printer for their template before you design anything — every mail house has one, it's a PDF with the clear zones marked, and it's the real spec, not a blog post's approximation, mine included. Then draw those clear zones as visible boxes in your layout and delete them at export. If the empty space isn't drawn, someone will fill it.
One offer, one code, one date
A postcard that says "we do windows, gutters, solar panels, roof moss, and conservatories" gets no calls. Not because nobody wants their gutters cleaned — because they were handed a research project instead of a decision. One offer, three parts:
- A number they can compare. "$49 first clean (usually $89)" beats "great rates."
- A code. MAIL49. It's the only thing that will tell you whether the drop worked, and it costs you nothing to print.
- A date. "Book by 30 September." Without it, the card goes into the drawer where good intentions die.
If you add a QR code, put it on the picture side and give it a white patch to sit on — dark codes over photos fail more often than people expect. There's a whole post on making QR codes people actually scan if you're leaning on it as the main response path.
What dies at the cut
Printed postcards get guillotined in stacks, and the cut drifts by a couple of millimetres. Two numbers cover you:
- Bleed: extend every background colour and photo 0.125" (3mm) past the trim on all four sides. Miss this and you get a white hairline down one edge of half the batch.
- Safety margin: keep all text and logos 0.25" (6mm) inside the trim.
Stock matters more here than on anything else you print, because the reader is holding it. 14pt or 16pt, gloss front and matte back — a glossy address side smears when the barcode printer hits it.
The worked example: a window-cleaning postcard, both sides
Here's the full piece, 6×9, mailed to about 600 houses inside a two-mile radius.
Address side. Background navy, full bleed. Top-left, in white at 38pt: "Your windows, done Thursday." Under it at 20pt in pale blue: "$49 first clean — usually $89." Bottom-left of the usable column, small: "Fairview Window Cleaning · fairviewwindows.co". The right half is empty navy for the address block; the bottom 5/8 inch is white and completely empty, right across the card. Nothing else on that side.
Picture side. Top two-thirds: one photograph — a bay window with hard afternoon light coming through it, shot from inside a living room. Not a stock photo of a squeegee. Bottom third on a white panel:
- Headline, 28pt: "Streak-free, or we come back."
- Three lines, 14pt: "Inside and out · Frames and sills wiped · 90 minutes for a typical semi"
- A blue badge, top-right of the panel: $49
- Phone at 22pt, then small: "Quote code MAIL49 · book by 30 September"
Two sides, one offer, one measurable code. Nothing on it that requires a second reading.
Building the postcard in Ridvay Studio
You don't have to lay that out by hand. Paste this into Ridvay Studio:
Design a 6x9 direct mail postcard, two pages, for Fairview Window Cleaning. Page 1 is the address side: navy full-bleed background, headline "Your windows, done Thursday." top-left, subline "$49 first clean — usually $89", small business name at the bottom left, and the entire right half plus the bottom 5/8 inch left empty for the address block. Page 2 is the picture side: a photo of a sunlit bay window across the top two thirds, then a white panel with the headline "Streak-free, or we come back.", three short service lines, a blue $49 badge, a phone number, and "Quote code MAIL49 · book by 30 September". Navy and white, one bold sans headline font.
What comes back isn't a flat JPEG you have to re-prompt to change. It's an editable design — the headline is a text layer with its own font and size, the navy background is a shape, the $49 badge is a shape plus text, the photo is a swappable image layer. Both sides come back as two pages of the same design, so the fonts and colours stay locked together.
Then make it yours, in this order:
- Draw the clear zones first. Add a plain rectangle over the right half of page 1 and a second one across the bottom 5/8 inch, in a colour you'd never print. Now you can see what you're not allowed to touch. Delete both before you export.
- Push the hook line up. Click the headline, drag the size up until it fills the left column, then pull the line spacing in. Address-side type is almost always too polite — this is the line doing the two-second work.
- Swap the photo for your own. Click the image layer and drop in a real job you did. No photo yet? Generate a placeholder in Ridvay Images — but a real window in a real house beats anything generated, every time.
- Apply your brand kit. Your palette and fonts snap onto both pages at once, so the card matches the van and the invoice. If you haven't set one up, it takes about ten minutes and every future design inherits it.
Export at 300 DPI with bleed, send both pages to the mail house, done.
Start your postcard with this prompt →
After the drop: what to actually measure
Count code redemptions, not impressions. If 600 cards produce eleven MAIL49 bookings, you know your cost per customer to the cent — and you know it because you printed a code, not because you felt good about the design.
Then change one thing and mail again. New hook line, same everything else. Because the design is layers rather than a flattened image, version two takes minutes: duplicate it, retype the headline, re-export. That's what makes testing realistic for a two-person business — not the first card, the fourth one.
The rest is physics. The card lands face-down, somebody's standing over a bin, and you get two seconds on a side you probably weren't planning to design.