Postcard Size: Standard Dimensions & USPS Mailing Rules
The standard postcard size is 4 Ć 6 inches. Learn USPS postcard dimensions, mailing rules, common postcard sizes, and postage requirements.
This guide explains standard postcard dimensions, USPS mailing limits, popular postcard formats, and how postcard size affects postage costs.
š® Standard Postcard Size
The standard postcard size is 4 Ć 6 inches. It qualifies for USPS postcard postage and easily passes through automated mail sorting equipment.
š USPS Postcard Size Rules
| Rule | Measurement |
|---|---|
| Minimum Size | 3.5 Ć 5 inches |
| Maximum Size | 4.25 Ć 6 inches |
| Thickness | 0.007ā0.016 inches |
š Common Postcard Sizes
4 Ć 6
Standard USPS postcard size with the lowest mailing cost.
5 Ć 7
Popular for invitations, greeting cards, and artwork.
6 Ć 9
Marketing postcards that stand out in the mailbox.
Rack Card
3.5 Ć 8.5 inches for travel displays and brochures.
š Postcard Size vs A5 & A6
A6 (105 Ć 148mm) is the closest ISO paper size to a standard postcard, while A5 (148 Ć 210mm) is much larger and closer to a 5Ć7 postcard.
š Postage by Postcard Size
| Postcard Size | Postage |
|---|---|
| 4 Ć 6 | USPS Postcard Rate |
| 5 Ć 7 | First-Class Letter Rate |
| 6 Ć 9 | Letter or Flat Mail Rate |
| 8.5 Ć 11 | Flat Mail / Letter |
šØ Common Design Mistakes
Skip Bleed
Always include bleed to prevent unwanted white edges after trimming.
Safe Margins
Keep important text away from postcard edges to avoid trimming.
Wrong Size
Exceeding USPS limits increases mailing costs.
ā Frequently Asked Questions
Are postcards typically 4Ć6 or 5Ć7?
4Ć6 is the standard USPS postcard size. 5Ć7 is common but mails at the letter rate.
Can I mail a 5Ć7 card as a postcard?
No. A 5Ć7 card exceeds USPS postcard size limits and requires First-Class letter postage.
Is a postcard A5 or A6?
Neither exactly. A6 is closest to a standard postcard, while A5 is considerably larger.
Can you mail an 8.5Ć11 postcard?
Yes, but it is mailed as a letter or flat, not as a USPS postcard.
What are USPS rules for postcards?
Cards must measure between 3.5Ć5 and 4.25Ć6 inches with a thickness between 0.007 and 0.016 inches.
How much postage do I need for a 5Ć7 postcard?
A First-Class Mail letter stamp is required.
Does a 6Ć9 postcard require extra postage?
Yes. It exceeds USPS postcard dimensions and is mailed at the letter or flat rate.
Do postcards just need one stamp?
Only standard-size postcards qualify for USPS postcard postage. Larger postcards require letter postage.
What are common postcard design mistakes?
The most common mistakes are skipping bleed, placing text too close to the edge, and exceeding USPS size limits.
See Related Dimensions:
Hi, Iām John Smith, the admin at BedDimensionsChart.com. I make measurements simple and easy to understand, from bed sizes to everyday length conversions. Clear guides. Accurate dimensions. No confusion.
