USPS Large Envelope Rate


March 25, 2024

If you’re looking for a reliable and affordable option for mailing standard-sized letters and postcards, look no further than the United States Postal Service’s First-Class Mail.

It offers one- to five-business-day delivery with prices starting at as low as $0.51, making it the go-to choice for many mailers. However, the key word here is “standard-sized.” First-Class Mail has strict size and shape requirements.

According to the U.S. Postal Service (USPS), a standard letter must be at least 3½” by 5” in height and length and 0.007” thick but cannot be over 6⅛” high, 11½” long, and ¼” thick.

On the other hand, a standard postcard should be at least 3½” by 5” in height and length and 0.007” thick but shouldn’t exceed 4¼” high, 6” long, and 0.016” thick.

So, what happens if your mailpieces surpass these dimensions? Does that mean you won’t be eligible for the stellar offerings of First-Class Mail? Fortunately, USPS provides some leeway in the form of its large envelopes.

This article discusses large envelopes, covering everything from postage costs to size and weight restrictions. 

For additional information on sending mail and packages through USPS, visit your local post office. Quickly find your area’s nearest Postal Service facilities with

What Are Large Envelopes?

In a nutshell, large envelopes or “flats” refer to mailpieces that differ in size and shape from standard or First-Class Mail letters and postcards. In other words, these are envelopes with one dimension exceeding 6⅛” high, 11 ½” long, or ¼” thick.

Fortunately, large envelopes still qualify for the First-Class Mail service. However, they must also meet size, shape, and weight requirements. The maximum size for a flat is 12” high, 15” long, and ¾” thick. At the same time, the maximum weight of a parcel is 13oz.

If your First-Class large envelopes exceed the maximum dimensions and weight limit, you may be forced to mail these shipments via other methods and pay package rates.

Before July 9, 2023, the mailing service for oversized large envelopes is First-Class Package. However, USPS combined it with Parcel Select Ground to create a new mail class called Ground Advantage.

How Much Does It Cost to Ship a Large Envelope?

The cost of shipping a large envelope through USPS First-Class Mail depends on various factors, including weight and any additional services or special features you choose.

But considering that flats exceed standard letter and postcard sizes, sending them should be expensive, right? Luckily, the First-Class Mail service is the Postal Service’s most economical option for mailpieces weighing up to 13oz.

While large envelopes no longer qualify for the starting prices of $0.66 and $0.51 for letters and postcards, respectively, their postage costs aren’t much more expensive.

Let’s break down the USPS rate for First-Class Mail flats.

USPS First-Class Mail Flats | Retail

Here’s an overview of the retail rates for sending a large envelope through the USPS First-Class Mail service based on the U.S. Postal Service’s October 2023 price list:


It’s essential to understand that these prices can change periodically. For up-to-date postage costs, visit your local post office and talk to a Postal Service representative. Use’s USPS facility locator tool to find your area’s most convenient post office location.

How Much Does It Cost to Mail a 9” x 12” Envelope?

A 9” by 12” envelope still fits a flat’s maximum dimensions of 12” by 15”. The cost of mailing an envelope of this size will depend on the mailpiece’s weight.

For instance, sending a 9” x 12” envelope weighing 4oz via First-Class Mail will cost you, as of October 2023, $2.07. However, the postage rate to ship a 13oz 9” x 12” flat will be $4.23. 

How Much Does It Cost to Mail an 8.5” x 11” Envelope?

As mentioned, an envelope with a size of 8.5” by 11” still meets the size restrictions of a First-Class Mail large envelope. Therefore, the price to mail one will vary based on its weight.

However, if you exceed the 13oz weight limit, you must send your 8.5” x 11” envelope via a different USPS service. Note that the postage cost of services like USPS Ground Advantage considers the distance between the origin and destination point or how many “zones” the parcel will travel.

For example, if your 8.5” x 11” envelope weighs 15oz, and the delivery address is between 301 and 600 miles (Zone 4) via Ground Advantage, you’ll pay $18.60. On the other hand, the price to mail a 20oz envelope traveling 151 to 300 miles (Zone 3) is $19.60.

What Is First-Class Mail Shape-Based Pricing?

You must meet size and weight requirements to send letters, postcards, and flats through the U.S. Postal Service’s First-Class Mail option. However, you must also follow parcel shape guidelines.

Generally, mailpieces shipped via First-Class Mail, including large envelopes, must be uniformly thick, rectangular, and not rigid. However, unlike letters, which incur a $0.40 nonmachinable surcharge, irregularly shaped flats will be shipped with USPS Ground Advantage.

Mail in 1–5 Business Days; Small Packages in 1–5 Business Days

First-Class Mail offers reliable and reasonable delivery times, with letters, postcards, and small packages shipped in large envelopes typically arriving between one and five business days.

According to the U.S. Postal Service, its First-Class Mail service is its least expensive mail and package delivery option for items weighing up to 13oz. It’s also eligible for special services that offer delivery confirmation, such as Certified Mail.

Features and Pricing

From personalized letters and essential documents to invoices or lightweight merchandise, First-Class Mail is designed to deliver your mail reliably, swiftly, and at a cost-effective shipping rate.

Here’s what else you must know about this USPS mailing solution.


You have two options for paying the shipping cost of a First-Class Mail letter. One is to buy postage stamps and stick them onto the letter. The other is to print postage directly onto the parcel using a postage meter.

You can expect to pay as little as $0.66 for a standard-sized stamped rectangular envelope. On the other hand, metered mail prices begin at $0.63. The Postal Service charges $0.24 for every additional ounce up to 3.5oz.

Here are the USPS rates for First-Class Mail letters:

Stamped First-Class Mail Letters
Metered First-Class Mail Letters

However, if you’re dealing with square, oversized, or unusually shaped envelopes, whether stamped or metered, the postage cost will incur an extra $0.40 fee. Thus, the starting prices will be $1.06 for stamped envelopes and $1.03 for metered envelopes.


Sending postcards is a breeze with First-Class Mail. Standard-sized rectangular postcards cost only $0.51. That said, you’ll pay $0.66 or the First-Class Mail letter rate for oversized postcards.

Small Packages

If you want to send items that exceed the size or weight limits for letters and postcards, you can opt for First-Class Mail flats. Doing so allows you to mail items up to 13oz while ensuring delivery within one to five business days for a starting price of $1.35.

Weight, Size, and Shape Requirements

You must follow the weight, size, and shape requirements to ensure your mailpieces qualify for the U.S. Postal Service’s First-Class Mail service. Otherwise, you may need to use other mailing options, such as Ground Advantage, with postage beginning at $4.75.

Here’s a quick look at the size and weight standards for First-Class Mail:

Minimum SizeMaximum SizeMinimum ThicknessMaximum ThicknessMaximum Weight
First-Class Mail Postcards3½” x 5”4¼” x 6”0.007”0.016”3.5oz
First-Class Mail Stamped Letters3½” x 5”6⅛” x 11½”0.009”¼”3.5oz
First-Class Mail Metered Letters3½” x 56⅛” x 11½”0.009”¼”3.5oz
First-Class Mail Flats6⅛” x 11½”12” x 15”¼”¾”13oz

Additional Charges for Irregular Mailpieces, Envelopes, and Small Packages

As mentioned, the size of your mailpiece significantly affects whether you can mail it through First-Class Mail. However, you must also consider its shape, as USPS applies additional charges for irregular letters, postcards, and large envelopes.

Nonmachinable Envelopes

Nonmachinable envelopes encompass various shapes, including square or vertical envelopes, rigid envelopes, lumpy envelopes, and those with clasps, buttons, or strings.

These irregular mailpieces must be hand-canceled by Postal Service workers instead of USPS’ automated machines and thus will incur a nonmachinable surcharge, even if they’re under 1oz.

Large Mailpieces, Envelopes, and Small Packages

Unfortunately, the U.S. Postal Service treats flats differently. To explain, parcels that exceed the maximum dimensions or deviate from uniform thickness criteria for First-Class Mail large envelopes will be charged package prices.

In other words, USPS will require you to ship these packages using USPS Ground Advantage or other delivery services instead of charging you the $0.40 nonmachinable surcharge they levy on First-Class Mail letters and postcards.

Additional Information

Here are some additional details you may want to know and consider before you ship your letters, postcards, and parcels via USPS’ First-Class Mail service:

Mailing Restrictions and Prohibitions

The U.S. Postal Service prohibits and limits you from shipping specific items through its First-Class Mail service and other package delivery solutions. These prohibitions include ammunition, marijuana, and hazardous materials (HAZMATs) like poisons.

For a comprehensive list of what you can and cannot mail through the U.S. Postal Service, visit 

You can also consult a Postal Service representative at your local post office, which you can find using’s locator tool.

For Businesses

First-Class Mail can benefit individuals looking for speed, security, and affordability. However, this USPS service isn’t limited to personal correspondence.

Whether you’re a small retailer or an eCommerce enterprise, USPS’ First-Class Mail service can help streamline your mailing processes and reduce costs.

Data-driven Shipping

First-Class Mail provides businesses with targetable, trackable, and measurable options, making it the ideal solution for sending messages to a wide audience at around half the price of shipping through USPS Media Mail. 

Commercial First-Class Mail also comes with address correction and forwarding services. In other words, mailing via this USPS option increases the chances of reaching potential customers and clients.

Commercial Prices and Automation Discounts

If you’re a business that requires a high-volume shipping service, you’ll want to consider First-Class Mail. You’ll qualify for commercial base pricing for a minimum quantity of 500 mailpieces.

You’ll receive further discounts if you send presort- and automation-compatible postcards and letters, allowing you to pay one price up to 3.5oz.

Presorted mail items refer to those that have been bundled by ZIP code. At the same time, automation-compatible mailpieces meet the basic standards for First-Class Mail, are sealed, and meet the paper weight guidelines, among other requirements.

For more information on how you can receive commercial prices and automation discounts for your First-Class Mail shipments, visit your local post office. Find your nearest U.S. Postal Service facility with

Cost of First-Class Stamps

One of the most significant advantages of picking First-Class Mail as your letter, postcard, and large envelope delivery solution is that you can use First-Class Mail or Forever stamps.

Letter Stamps

First-Class Mail stamps cost, as of October 2023, $0.66, always equal to the price of mailing a 1oz First-Class Mail letter. These stamps are also explicitly designed to maintain their value even if postage rates rise, hence why they’re also known as Forever stamps.

Note that there are also Additional Ounce Forever stamps, which you can use to cover the postage of subsequent ounces. As of October 2023, each Additional Ounce Forever stamp’s value is $0.24.

Postcard Stamps

Based on the U.S. Postal Service’s October 2023 price list, the cost of a postcard stamp is $0.51– the same as the shipping price of sending a postcard via First-Class Mail. 

Like Forever stamps, postcard stamps will always be valid regardless of future postage rate changes.

Global Forever® (International)

While you can use First-Class Mail stamps to pay the postage of sending postcards and letters via First-Class Mail International, you may need multiple stamps to cover the higher prices.

Enter Global Forever stamps. The cost of one of these stamps is, as of October 2023, $1.50 and is linked to the shipping rate of 1oz First-Class Mail International letter. You can also use this postage stamp to cover the cost of mailing a postcard to an international address.


Although the U.S. Postal Service’s First-Class Mail option is excellent for sending letters, postcards, and lightweight parcels via large envelopes, it isn’t USPS’ only offering.

Here’s an overview of USPS’ domestic and international service pricing:

Domestic Prices

ServicePost Office PriceCommercial Price
Priority Mail Express$28.75$24.90
Priority Mail Express Flat-Rate Envelope$28.75$24.90
Priority Mail Express Return$24.90
Priority Mail$9.35$7.64
Priority Mail Flat Rate Envelope$9.65$8.05
Priority Mail Return$7.65
First-Class Mail$0.66$0.49
USPS Ground Advantage$4.75$3.59
USPS Ground Advantage Return$4.75$3.59
USPS Marketing Mail$0.19
Parcel Select$3.78
Parcel Select Lightweight$2.46
Media Mail$3.92$2.59
Library Mail$3.72$2.46

International Prices

ServicePost Office PriceCommercial Price
Global Express Guaranteed$71.10$67.55
Priority Mail Express International$56.00$53.07
Priority Mail Express International Flat-Rate$54.75$51.98
Priority Mail International$42.10$39.53
Priority Mail International Flat-Rate Envelope$30.35$28.57
Priority Mail International Small Flat-Rate Box$31.45$29.64
Priority Mail International Medium Flat-Rate Box$60.55$56.10
Priority Mail International LargeFlat-Rate Box$74.00$69.10
First-Class Package Service$15.75$14.96
Airmail M-Bag$55.00$30.00 (International Priority Airmail M-Bag)$30.00 (International Surface Air Lift M-Bag)
International Business Reply Service$2.10

First-Class Commercial Parcel or Package Rate Changes

Effective July 9, 2023, and still valid as of October 2023, the commercial rate for First-Class Package or USPS Ground Advantage is as follows:

Weight not overZone 1(1-50 miles)Zone 2(51-150 miles)Zone 3(151-300 miles)
Weight not overZone 4(301-600 miles)Zone 5(601-1000 miles)Zone 6(1001-1400 miles)
Weight not overZone 7(1401-1800 miles)Zone 8(over 1801 miles)Zone 9(U.S. territories and some military addresses)

Info on the USPS Postage Rate Increase

Effective July 9, 2023, USPS increased its pricing for First-Class Mail. These changes include increasing the rates of First-Class Mail stamps from $0.63 to $0.66. 

The increase also affected the shipping price of postcards from $0.48 to $0.51 and the base postage of large envelopes from $1.26 to $1.35.

Summary of the Postage Rate Increase

Here’s a summary of the July 9, 2023 First-Class postage rate increase:

ProductPrevious PricesNew Prices
First-Class Mail 1oz stamped letter$0.63$0.66
First-Class Mail 1oz metered letter$0.60$0.63
First-Class Mail postcard$0.48$0.51
First-Class Mail International 1oz letter$1.45$1.50

First-Class Mail Quick Tips

Here are some quick tips to help you understand the nuances of shipping via First-Class Mail and simplify the mailing process:

  • Letter-sized, square greeting cards are priced based on letter rates. It will also incur the $0.40 nonmachinable surcharge.
  • Even if a mailpiece meets the size and weight requirements but is rigid, it will be classified and priced as a nonmachinable letter.
  • The nonmachinable surcharge specifically applies to First-Class Mail letters. It doesn’t extend to standard-sized postcards and large envelopes.
  • If a piece of First-Class Mail exceeds any one of the maximum dimensions, you’ll pay the cost of the next larger shape.
  • You can mail padded bags, like ReadyPost cushion mailers, through First-Class Mail if they meet flats’ size, weight, and shape requirements.


While the U.S. Postal Service is a popular choice for sending large envelopes and small packages, UPS (United Parcel Service) also offers reliable shipping services.

Unfortunately, whether one is more suited for your mailing needs depends on numerous factors, such as the available services and costs. 

To help you weigh your options, visit your local post office. Quickly find your area’s most convenient USPS facilities with

Frequently Asked Questions

  1. Does First-Class Mail have tracking?

Unfortunately, First-Class Mail doesn’t include end-to-end monitoring. However, you can purchase extra services to receive tracking information on your First-Class Mail items.

Other add-ons you can buy for your First-Class Mail shipment include Signature Confirmation, Return Receipt, Registered Mail, Collect on Delivery, Certificate of Mailing, and insurance coverage.

  1. How do you send First-Class Mail?

Sending your First-Class Mail is straightforward: prepare your letter, postcard, or flat, properly address it, pay the postage, and drop it off at a post office or collection box or ask USPS to pick up your parcel.

  1. How long does First-Class Mail take?

While the delivery time for First-Class Mail items can vary, the U.S. Postal Service ensures they arrive within one to five business days.

  1. What is considered First-Class Mail?

First-Class Mail can be letters, postcards, and large envelopes that meet the size, shape, and weight requirements. 

The maximum dimensions for letters are 6⅛” high, 11½” long, and ¼” thick; 4¼” high, 6” long, and 0.016” thick for postcards; 12” high, 15” long, and ¾” thick for flats.

  1. Does First-Class Mail have insurance?

Unlike other Postal Service mailing solutions, such as USPS Priority Mail and Ground Advantage, First-Class Mail doesn’t automatically come with shipping insurance. However, you can purchase coverage as extra services.

  1. How much is First-Class Mail?

The shipping price via First-Class Mail varies on the mailpiece’s size, shape, and weight. The starting prices for letters, postcards, and large envelopes are $0.66, $0.51, and $1.35, respectively.

  1. Can I use Priority Mail boxes for First-Class Mail?

Containers labeled “Priority Mail” must only be used for shipping via the Priority Mail service. In other words, you cannot use a Priority Mail box for First-Class Mail.

  1. Is Priority Mail faster than First-Class Mail?

The earliest arrival for Priority Mail and First-Class Mail shipments is one day. However, the former’s latest delivery is within three days versus the latter’s five days. Ultimately, whether one is faster depends on the delivery location.

  1. What is presorted First-Class Mail?

In a nutshell, presorted First-Class Mail items are those that have been grouped together by ZIP code. The most significant benefit of presorting your First-Class Mail shipments is you may qualify for lower postage costs through commercial pricing.

  1. Is First-Class Mail regular mail?

The answer to whether First-Class Mail is regular mail depends on your definition of “regular.” If your definition of “regular” means traditional letter, postcard, and large envelope delivery, then yes.

However, if you consider reliable and economical shipping as “regular,” there’s nothing “regular” about First-Class Mail.

  1. What is the difference between First-Class Mail and Priority Mail?

The most noteworthy distinction between Priority Mail and First-Class Mail is the weight limits. 

Priority Mail lets you ship mailpieces up to 70lbs, giving you the flexibility to send bigger and heavier items. On the other hand, First-Class Mail only allows up to 13oz.

  1. Can you use flat-rate boxes for First-Class Mail?

USPS’ flat-rate products, such as legal flat-rate envelopes, let you send items up to a specific weight to any state at the same price. Unfortunately, flat-rate boxes are only available for Priority Mail and Priority Mail Express.

In short, you can’t use flat-rate boxes to ship via the U.S. Postal Service’s First-Class Mail option.

  1. How many stamps should I put on a 9” x 12” envelope?

A 9” by 12” envelope still qualifies as a flat. In other words, you can still send it via First-Class Mail. However, the number of stamps you must stick to that envelope depends on the weight.

For instance, if it weighs 7oz, you must use a combination of stamps to cover the $2.79 postage cost. In this scenario, you can use four First-Class stamps and a $0.15 denominated stamp ([$0.66 x 4] + $0.15 = $2.79).

Talk to a Postal Service representative at your local post office to receive assistance in calculating your postage costs and the number of stamps you should use.

However, there are over 31,000 post offices nationwide, which can make it challenging to receive immediate help. Fortunately, you can visit and use the USPS facility finder to locate ones in your area.


  1. First-Class Mail
  2. Sizes for Letters
  3. Sizes for Postcards
  4. Sizes for Large Envelopes and Flats
  6. USPS Price List
  7. What are Zones, and how do they affect your shipping costs?
  8. Types of First-Class Mail®
  9. What is a postage meter?
  10. Domestic Shipping Prohibitions, Restrictions, & HAZMAT
  11. Presorting Your Mail
  12. Mailing & Shipping Prices
  13. Forever Stamp Fact Sheet
  14. Postage Stamps – The Basics
  15. U.S. Postal Service Files Notice with PRC for New Mailing Services Pricing
  16. First-Class Mail Fact Sheet
  17. Insurance & Extra Services
  18. How to Send a Letter or Postcard: Domestic
  19. Carrier Pickup Free Pickup Saves a Trip to the Post Office
  20. 2022 USPS First Class Mail Postal Rates
  21. Priority Mail
  22. Priority Mail Express