Postcard Size
The standard US postcard is 6 × 4 inches (152.4 × 101.6 mm) — the USPS standard postcard rate size. At 300 DPI it's 1800 × 1200 pixels. For direct mail, keeping dimensions within 6 × 4.25 in qualifies for postcard postage rates (significantly cheaper than letter rates in the US).
Specifications
| Pixels | 1800 × 1200 px (at 300 DPI) |
| Millimetres | 152.4 × 101.6 mm |
| Centimetres | 15.2 × 10.2 cm |
| Inches | 6 × 4 in |
| Aspect ratio | 3:2 |
| Colour mode | CMYK |
| Bleed | 3 mm (0.125 in) |
| Safe zone | 5 mm (0.25 in) from trim |
Postcard in Pixels at Different DPI
The pixel count changes with DPI setting — choose the right one for your output.
| DPI | Width (px) | Height (px) | Use |
|---|---|---|---|
| 72 | 432 | 288 | Screen preview, PDF viewers |
| 96 | 576 | 384 | Windows screen standard, digital documents |
| 150 | 900 | 600 | Medium-quality print, home printers |
| 300 | 1,800 | 1,200 | Professional print, commercial offset |
Design Tips
- →For USPS postcard rate (cheaper than letter rate), keep dimensions between 3.5–6 in long and 3.5–4.25 in tall with a thickness of 0.007–0.016 in.
- →Reserve the back of the postcard for addressing: a 3.5 in × 4 in address area on the right half, and a message area on the left half, following USPS layout standards.
- →For marketing postcards, the front face (6 × 4 in) should have one dominant image and one call-to-action — postcards are read in seconds, not studied.
- →Use 14–16 pt minimum text for any content you want to be readable after USPS handling — postcards can be printed slightly out of focus at high-speed inkjet production print.
Create Postcard designs with Playyy
Set a custom canvas to 1800 × 1200 px, generate visuals from a text prompt, and export at the right dimensions — no design software needed.
Start designing free →Frequently Asked Questions
What is standard postcard size?+
Standard US postcard size is 6 × 4 inches (152.4 × 101.6 mm). At 300 DPI, that's 1800 × 1200 pixels. For USPS postcard postage rates, cards must be between 3.5–6 in long and 3.5–4.25 in tall. The 4×6 size is the most common.
What is the difference between a postcard and an A6 card?+
A US standard postcard is 6 × 4 in (152.4 × 101.6 mm). An A6 card is 148 × 105 mm (5.83 × 4.13 in). The postcard is slightly larger. A6 is the international standard postcard size used outside North America. Both fit in standard postcard envelopes.