Postcards vs Letters vs Flats: A Comprehensive Comparison

May 24, 2020

When it comes to sending mail, whether for personal or business purposes, understanding the differences between postcards, letters, and flats can help you make the right choice for your specific needs. In this detailed guide brought to you by Re-View Business Strategies - a leading provider of Consulting & Analytical services in the field of Business and Consumer Services - we will explore the characteristics, advantages, and optimal usage scenarios for each mailing option.


Postcards are a popular choice for quick and concise messaging. Typically, they are printed on sturdy cardstock and feature a striking visual design on one side, with space for a message, recipient address, and postage on the other side. Postcards are a cost-effective way to deliver a brief message or advertisement directly to your target audience.

Advantages of Postcards:

  • Eye-catching design and visuals
  • Lower postage rates compared to letters and flats
  • Quick and easy to read
  • Great for promotional campaigns


Letters offer a more personalized and detailed approach to communication. They provide ample space for a customized message, business proposal, or formal correspondence. Letters are typically enclosed in envelopes for added confidentiality and protection during transit.

Advantages of Letters:

  • Personalized content for a tailored message
  • Formal and professional communication
  • Envelopes offer privacy and protection
  • Suitable for detailed information or legal documents


Flats refer to larger mailpieces that do not meet the dimension requirements of letters but are not as rigid as parcels. Flats are commonly used for sending catalogs, magazines, books, or other bulky items that cannot fit into a standard envelope.

Advantages of Flats:

  • Spacious layout for bulky or folded items
  • Visible design elements for branding
  • Effective for promoting products or services
  • Can include additional marketing materials

USPS Regulations on Mailings

It is essential to be aware of the USPS regulations when choosing between postcards, letters, and flats. The United States Postal Service (USPS) has specific guidelines for size, weight, and design requirements for each type of mailing.

Differences in USPS Regulations:

  • Postcards must meet specific size and weight restrictions
  • Letters require standard envelope sizes for automated processing
  • Flats have dimensional limits to qualify for flat mailing rates
  • Each category has unique postage rates and delivery timelines

Choosing the Right Mailing Option

At Re-View Business Strategies, we understand the importance of selecting the most suitable mailing option to achieve your marketing goals and meet USPS requirements. Our team of experts specializes in Consulting & Analytical services to help businesses optimize their direct marketing campaigns and postal strategies.

Whether you are considering postcards vs letters or exploring the benefits of flats for your next mailing project, our knowledgeable consultants can provide tailored recommendations based on your specific needs and budget.


In conclusion, postcards, letters, and flats each offer unique advantages and applications in the world of direct mail marketing. By understanding the differences between these mailing options and adhering to USPS regulations, you can effectively reach your target audience and achieve your marketing objectives.

For expert guidance on optimizing your mailing strategy and maximizing the impact of your direct marketing efforts, contact Re-View Business Strategies today. Let us help you navigate the complexities of postal services and elevate your business communication to new heights.