Postcard sizes (US and A6) explained
The most common postcard is 4 × 6 inches; 5 × 7 in and jumbo 11 × 6.25 in give more room for photos and offers. Outside the US, A6 (148 × 105 mm) is standard. For US mail, only cards between 3.5 × 5 in and 4.25 × 6 in qualify for the cheaper USPS postcard price; larger cards go at letter or flat prices.
Postcard sizes compared
| Size | Inches | Millimetres | Good for |
|---|---|---|---|
| Standard | 4 × 6 in | 102 × 152 mm | Thank-you notes, reminders, appointment cards; qualifies for US postcard postage |
| Medium | 5 × 7 in | 127 × 178 mm | Offers with a photo, event invitations, menus |
| Large | 6 × 9 in | 152 × 229 mm | Direct mail that needs to stand out in the mailbox |
| Jumbo | 11 × 6.25 in | 279 × 159 mm | Neighbourhood mailings such as USPS Every Door Direct Mail |
| A6 | 5.8 × 4.1 in | 148 × 105 mm | The standard postcard in Europe, the UK, Australia and most other countries |
CatalogProFlow has postcard templates in 4 × 6 in, 5 × 7 in, jumbo 11 × 6.25 in and A6, all with bleed and a safe area. 6 × 9 in is listed here for reference because it's a popular direct-mail size.
Mailing postcards in the US
- USPS postcard price: the card must be rectangular, at least 3.5 × 5 in and no larger than 4.25 × 6 in, and between 0.007 and 0.016 in thick.
- Anything bigger than 4.25 × 6 in is charged as a letter or a flat, so a 5 × 7 or 6 × 9 in card costs more to mail.
- Leave the address side clear on the right half, and keep the bottom 5/8 inch free for the postal barcode.
- Every Door Direct Mail (EDDM) lets you mail to every address on a route without a mailing list. It has its own size and paperwork rules, so check the USPS EDDM page before you print.
Postal rules outside the US differ. Royal Mail, Canada Post, Australia Post and others publish their own size limits; check yours before printing a large run.
What goes on each side
| Side | What to include |
|---|---|
| Front | One strong photo and a headline: the offer, the event, or “Thank you” |
| Back, left half | A short message, the details (date, offer, expiry), your logo and a QR code |
| Back, right half | Return address, recipient address lines and the stamp or postage area |
Bleed, paper and files
- Bleed: 1/8 inch (3 mm) on every edge; keep text 1/8 inch inside the trim.
- Paper: 14 pt or 16 pt card is common for mailed postcards; it survives sorting machines better than thin card.
- Files: a PDF with bleed for the printer. In CatalogProFlow choose Export, then “PDF for a print shop” (Pro or a one-time unlock).
Plan the mailing before you design
- Decide who gets it: existing customers (you have addresses) or every home on a route (EDDM in the US, or door-to-door services elsewhere).
- Pick one offer with an end date so you can tell whether the mailing worked.
- Add a code or a QR code that's unique to this mailing.
- Order a few extra for the counter and for people who ask about the offer.
Questions
- What is the standard postcard size?
- 4 × 6 inches in the US; A6 (148 × 105 mm) in most other countries.
- What is the biggest postcard you can mail at the US postcard rate?
- 4.25 × 6 inches. Larger cards are charged as letters or flats.
- What size is an A6 postcard in inches?
- About 5.8 × 4.1 inches (148 × 105 mm).
- Can I make a postcard and mail it myself?
- Yes. Download the PDF, print it on card stock or at a print shop, add stamps or postage, and post it like any other card.