What Is First-Class Mail?
March 2, 2020
2 Minutes
First-Class Mail®…we use it all the time to mail letters, postcards and maybe even large envelopes. But what is it and how much does it cost?
First-Class Mail is the USPS's most popular and economical service. That's not all that makes it great! First-Class Mail delivers anywhere in the United States in 1-3 days, for a low cost.
You are probably already familiar with sending letters via First-Class Mail, but did you know you can also send postcards and large flat envelopes? You can! Each item has different size and weight specifications outlined in the handy chart below.
These details are important to reference because, if your letter is too big or too heavy, it might not be delivered and it could be returned delaying important communications and costing you more time and money.
Table
Mail Item | Width | Length | Thickness | Weight |
|---|---|---|---|---|
Postcard | 4.25" max | 6" max | .016" max | n/a |
Letter | 6.125" max | 11.5" max | .25" max | 3.5 oz, each additional ounce has a price per ounc |
Large Flat Envelope | 12" max | 15" max | .75" max | 13 oz. max |
Table
How much is First-Class Postage?
The most common item sent via First-Class Mail is your standard 1-ounce letter which requires one stamp worth 55 cents or 50 cents if you use a postage meter. If you are sending mail that is heavier than 1 oz., like multi-page documents or wedding invitations, you will be charged .15 cents for each additional ounce and need to apply additional postage.
The last thing you want to do is underpay and have your important letter returned. The best way to avoid this is to take heavier letters to the Post Office™ or use a postage meter to stamp them at home or in the office. Postage meters come equipped with a scale so you can weigh your mail so you never under or overpay for postage.
Prices also vary depending on your mail item. To see how much each item (postcards, letters, and large envelopes) cost to mail, check out our chart below.
Table
Mail Item | First-Class Mail Rate 1 oz. - Stamps | First-Class Mail Rate 1oz.- Metered |
|---|---|---|
Postcard | $.35 |
|
Letter | $.55 | $.50 |
Large Flat Envelope | $1.00 |
|
Table
For a more detailed listing check out the USPS's full list of postal rates.
Have more questions about USPS First-Class Mail? Send them to us! If you’d like to learn more about Priority Mail® and Priority Mail Express®, check out our FAQ blog post and find here the current postal rates.
Related Content
Discover the latest articles, guides, case studies, and industry updates to help you stay ahead of changing customer expectations, emerging technologies, and market trends.

What are the top mail automation trends and best practices for 2026?
Discover the top mail automation trends for 2026, including hybrid delivery, cloud workflows, compliance, and cost optimization. Learn best practices to improve accuracy, reduce costs, and deliver reliable customer communications.

How much can I save with a postage meter?
A postage meter can save 4–6¢ per First-Class letter while reducing labor, errors, and post office trips. See real savings examples by mail volume.

2026 Canada Post Rate Changes
Lettermail rates remain unchanged for 2026, with only a small 1 cent increase to Personalized Mail. Personalized Mail still offers strong value for targeted communication, and Quadient is here to support customers.











