Postcard dimensions
The standard postcard size is 152.4 × 101.6 mm (6 × 4 inches), or 1800 × 1200 pixels at 300 DPI.
Last updated:
Specifications
| Spec | Value |
|---|---|
| Dimensions (px) | 1800 × 1200 px |
| Aspect ratio | 3:2 |
| Size (inches) | 6 × 4 in |
| Size (cm) | 15.24 × 10.16 cm |
| Size (mm) | 152.4 × 101.6 mm |
| Supported formats | PDF, PNG, JPG, TIFF |
| Color mode | CMYK |
| Bleed | 3 mm (0.118″) |
Print zones
| Zone | Dimensions | Purpose |
|---|---|---|
| Trim | 6 × 4″ | Final cut size |
| Bleed | 6.25 × 4.25″ | Design canvas (extends past trim) |
| Safe area | 5.75 × 3.75″ | Keep text and logos inside this zone |
All supported sizes
| Format | Dimensions | Aspect ratio |
|---|---|---|
| Standard (6×4") | 1800 × 1200 px | 3:2 |
| Jumbo (5×7") | 2100 × 1500 px | 7:5 |
Postcard in pixels at different DPI
| Resolution | Width | Height | Use case |
|---|---|---|---|
| 72 DPI | 432 px | 288 px | Screen / web |
| 96 DPI | 576 px | 384 px | Windows default |
| 150 DPI | 900 px | 600 px | Draft print / large posters |
| 300 DPI | 1800 px | 1200 px | High-quality print |
Design at this size with Moda
Start with a canvas pre-set to 1800×1200px and let AI generate your design.
Create a postcard →Design tips
The standard US postcard is 6×4 inches (152.4×101.6mm). At 300 DPI, that's 1800×1200 pixels. This is the most common mailable postcard size and qualifies for USPS First-Class postcard rates, which are cheaper than letter rates.
- •Design at 1800×1200px (300 DPI) with 3mm bleed for the standard 6×4" postcard.
- •Keep within 3.5×5" to 4.25×6" to qualify for USPS postcard rates (cheaper than letter rates).
- •Reserve the right half of the back for address and postage — USPS requirement for mailable postcards.
What you need to know
The 6×4 inch postcard is the most common size in the US and qualifies for the cheapest USPS mailing rate (First-Class postcards). USPS requires postcards to be between 3.5×5 inches (minimum) and 4.25×6 inches (maximum) for postcard rates. Anything larger ships at letter rates.
Larger postcard formats exist for marketing: 5×7 inch (jumbo), 5.5×8.5 inch (half-letter), and 6×11 inch (panoramic). These are popular for direct mail campaigns because the larger size stands out in a mailbox. However, they ship at First-Class letter rates, not postcard rates.
When designing postcards for mailing, the back side has specific layout requirements. USPS requires the right half of the back for the address and postage. The left half is available for your message or design. Include at least 0.25 inches of clear space at the top and bottom edges for postal barcodes.
How to create a postcard at the right size
- 1Open Moda and create a new canvas at 1800×1200 pixels.
- 2Design your postcard using AI generation or start from a blank canvas.
- 3Export as PDF and upload to your platform.
Frequently asked questions
What size is a standard postcard?
The US standard postcard is 6×4 inches (152.4×101.6mm). At 300 DPI, that's 1800×1200 pixels.
What's the maximum size for USPS postcard rates?
4.25×6 inches maximum. Minimum is 3.5×5 inches. Anything outside this range ships at letter rates.
What are common postcard sizes for marketing?
Standard: 6×4". Jumbo: 5×7". Half-letter: 5.5×8.5". Panoramic: 6×11". Larger sizes ship at letter rates.
What is the postcard size in cm?
Standard US postcard: 15.24 × 10.16 cm (6 × 4 inches).
What are the USPS postcard size limits?
Minimum: 3.5 × 5 inches. Maximum for postcard rates: 4.25 × 6 inches. Larger sizes ship at First-Class letter rates.
Specs last verified: March 19, 2026. Dimensions may change as platforms update their requirements.