Additional Ounce Stamp Cost


March 13, 2024

One primary concern consumers have regarding USPS (United States Postal Service) products is the cost of Additional Ounce stamps.

This article addresses the confusion surrounding the Additional Ounce stamp, including its pricing.

This article explains the significance of Additional Ounce stamps and how to use them.

It will also discuss how you can send domestic and international items with additional ounces of postage. 

If you want to buy stamps, visit your local post office and find their available stamps.

Check out and locate the nearest post office in your area. Our website contains information about U.S. (United States) post offices.

U.S. Postal Service Announces New Prices

USPS filed notice with the PRC (Postal Regulatory Commission) of mailing services price changes effective July 9, 2023.

The new rates involve a three-cent increase to the cost of a First-Class Mail Forever stamp, from $0.63 to $0.66.

U.S. Additional-Ounce, Postcard Rates to Go Up

Additional ounces (metered mail and post office) for First-Class Mail (FCM) letters increased in July 2023 by four cents (from $0.20 to $0.40).

Rates for one-ounce (1oz) FCM flats or large envelopes increased by four cents, from $1.16 to $1.20. Each additional ounce costs $0.24.

Holiday Shipping Rate Increase Info

USPS can impose a temporary shipping rate increase during the peak holiday season.

For instance, the carrier issued a rate increase last 2022, starting October 2, 2022 (Sunday) and ending January 22, 2023 (Sunday).

The rate increase affected Priority Mail Express, First Class Package Service, Parcel Select, Priority Mail, and USPS Retail Ground.

Info on the USPS Postage Rate Increase

On October 6, 2023, USPS proposed price adjustments for shipping services with the PRC to take effect on January 21, 2024. 

Summary of the Postage Rate Increase

This table shows the postage rate changes for some USPS services from January 2023 to July 2023:

ProductJanuary 2023 RatesJuly 2023 Rates
First-Class Mail (letters)$0.63$0.66
First-Class Mail (metered) $0.60$0.63
Domestic First-Class Mail postcards$0.48$0.51
International postcards$1.45$1.50

Here’s additional info regarding the current price of some USPS services:

  • Ground Advantage
    • Packages up to 15.999oz (formerly First-Class Package Service): No rate change
    • Packages weighing one pound (1lb) or more (formerly Parcel Select Ground): An average price drop of 1% overall, starting at $6.47 (previously $6.99)
  • Media Mail: An average 7% price increase on July 9, 2023, starting with $3.92 (previously $3.65)

Forever Stamp

Forever Stamps are always priced the same as a regular First-Class Mail stamp.

As the name suggests, Forever Stamps can mail a one-ounce letter forever, no matter when the stamps are purchased or used and regardless of how prices may change.

How Much Do Forever Stamps Cost?

Since July 9, 2023, Forever Stamps cost 66 cents or $0.66 per piece. 

The “Forever” signifies that even after the price increases, a Forever stamp you paid 66 cents (current rate) for will still send a one-ounce letter to any U.S. address. 

You will not have to add more postage to cover the price increase. 

You can still use a forever stamp bought 15 years ago for $0.42 to mail a First-Class letter today without additional postage.

The Cost of a Forever Stamp Increases by 2 Cents

USPS has announced that the price of a Forever stamp will increase by two cents on January 21, 2024. The stamp will increase from 66 cents to 68 cents.

U.S. Postal Service Wants to Hike Stamp Prices to 63 Cents

In April 2023, USPS got approval to hike stamp rates to 63 cents (¢) from 60 cents (¢).

The new price increase — which USPS said was necessary to offset the rise in inflation — took effect July 9, 2023, upon confirmation from the PRC.

Blame the Internet

The extensive use of email and the shift to online banking has affected the post office negatively.

People became less dependent on stamps for bills and letters. Businesses opted to reach their target audience with email instead of junk mail, as the former is more affordable and efficient.

The U.S. Post Office Department was founded in 1792 as a part of the federal government. The department was reorganized in 1970 as the United States Postal Service, an independent agency.

As a separate institution, the USPS receives nothing from taxpayer money for operating expenses.

In May 2021, USPS stated that the proposed postage price increases are a first step to counter a projected $160 billion operating loss over the next 10 years.

A 2006 law capped postage hikes at the consumer price index, the government’s primary inflation indicator. 

However, the same law allowed the PRC to review the impact of the postage price cap. Consequently, in 2017, the PRC determined that the price cap hurt USPS profitability. 

In November 2020, the PRC adopted new rules, giving USPS more flexibility regarding rate increases.

How Many Stamps Do I Need? The U.S. Mail Postage Explained

The answers to this question depend on the following factors:

  • Size of the letter
  • Mailing service, for example, First Class, Certified, or Registered Mail
  • Weight of the letter
  • The value of the stamps used 

How Many Postage Stamps Do I Need to Buy and Use When Sending a Letter?

The number of stamps you need to purchase and use when sending a letter depends on what mailing option you prefer.

For example, you can send 1oz (four sheets of printer paper and a business-sized envelope) using one First-Class Mail Forever stamp (currently $0.66).

Domestic Envelope Requirements and Costs

There are specific regulations for sending letters in an envelope. Therefore, you should measure your envelope before you buy it.

The envelope requirements are as follows:

  • The envelope must not exceed 11.5 inches by 6.125 inches, no thicker than 1/4 inch. It should also have a uniform thickness. 
  • The envelope should be rectangular. 

Square envelopes should be at least five inches in size, are regarded as “non-machinable,” and are subject to an additional postal charge. 

A “machinable” letter will pass through the USPS sorting systems smoothly. 

  • The envelope should be bendable. If not, it will be considered “non-machinable,” and you may have to pay an additional 21 cents. 

Flats Requirements and Costs for Flats

USPS uses “flats” to refer to large envelopes, magazines, and newsletters. 

Flats must meet the following size and shape requirements:

  • Have one dimension greater than 6 1/8 inches high, 11 ½ inches long, or 1/4 inch thick
  • Be no more than 15 inches long, 12 inches high, and 3/4 inches thick.

Suppose the mailpiece weighs over 3.5oz. In that case, you can send it as a flat (large envelope) and attach the appropriate number of postal stamps.

You need at least two Global Forever stamps to send a card or letter weighing over 3.5oz. 

Domestic Letter Mailing: Price per Ounce

The table below shows the estimated number of stamps you will buy to ship domestic mail according to the letters’ weight.

The Letter’s WeightThe Stamp Type and Number

1oz or less
One domestic Forever Stamp (55 cents per piece as of 2023)

One domestic Forever Stamp plus a 15-cent additional ounce stamp. This method might cost you 70 cents.

International Shipping Letter Postage

Postage rates for international shipments may vary depending on the destination.

As of 2023, here are the postage rates and delivery times for sending items to Canada via different USPS mail classes:

Mail ClassDelivery TimeRatesTracking
Priority Mail International6 to 10 business daysBegins at $37.47Included
Priority Mail Express International Flat Rate (Envelopes)Three to five business daysBegins at $44.95Included with date-specific delivery available
First Class Package International Service11 to 20 business daysBegins at $14.11Included for some countries
Priority Mail Express InternationalThree to five business daysBegins at $44.95Included with date-specific shipment available

Domestic Postcard Shipping

A typical postcard stamp costs $0.51. Square or large postcards will cost more. Place the postcard stamp in the provided area near the delivery address.

As mentioned, the First-Class Mail Forever stamp costs $0.66. This stamp goes in the envelope’s upper right. You can also use any stamp combination, provided it amounts to $0.66.

If your letter is bigger or heavier, or if you want extra insurance or an extra feature like Certified Mail service, you will pay more.

How Many Stamps Do I Need to Purchase and Use When Sending a Package to the U.S.?

As you know, USPS offers various mailing options for sending packages to the U.S. and other countries. 

However, the postage rate for USPS shipments will vary depending on your preferred product and delivery area. These factors determine the number of stamps you buy and use. 

Whether you use printed postage or stamps, you must affix the stamp at the top-right corner of your package.

The following options allow you to send domestic packages:

  • USPS Ground Advantage
  • Priority Mail Express
  • First-Class Mail
  • Priority Mail
  • Media Mail

Forever Stamps are ideal for mailing standard-sized, one-ounce letters within the U.S. 

Weigh your item before affixing a stamp to ensure it does not exceed the weight limit. USPS will return heavier letters for lack of postage.

For example, you must include additional postage to your Forever Stamp for any mail piece weighing more than one ounce.

Using a Postage Calculator

The Postal Service has developed an online calculator to make it more convenient for customers to estimate postage costs. 

To use this tool, you must know your mail’s weight, size, and class. If you already have this information, enter it into the USPS online postage calculator to determine the cost.

Calculating Postage at the Post Office

Some parcels may be too large to put in a postbox. Therefore, you must take the parcel to the post office to mail it. The retail counter personnel will give you the stamp price. 

Where to Buy the Stamps You Need and the Postage Costs

Here are several places and options to buy stamps and cover postage costs:

  • At a USPS Location: Use’s free online search tool to find nearby post office locations or approved third-party postal providers.
  • The Postal Store Online: Go to the Postal Store and order stamps or other USPS items online.
  • By mail: This option lets you purchase stamps through the mail using PS Form 3227-A (a stamp purchase order form). 

Your local post office will fulfill your stamp orders, and your letter carrier will deliver the stamps to you. PS Form 3227-A is available at post offices.

  • By phone: You can call 1-844-737-7826 for inquiries regarding stamps or orders submitted online through The Postal Store. 

You can also call this number to order stamps via phone. 


Postage for letters primarily depends on weight, size, and shape. You can weigh your letter using a kitchen scale, postal scale, at a self-service kiosk (SSK), or at the post office counter.

If your envelope weighs over 1oz, you can buy more postage as needed. 

Note: Each additional 1oz costs $0.24 for letters weighing up to 3.5oz and large envelopes weighing up to 13oz.

Flat Rate Envelopes

A USPS flat-rate envelope allows customers to send mail at a fixed rate, regardless of the destination. 

Flat-rate envelopes come in various sizes and materials, each with a fixed cost. 

International Mail and Packages

Many people use First-Class Mail International when sending international letters and large envelopes. This service lets you mail 1oz postcards or letters for only $1.50.

For other types of mailpieces, the destination may affect the postage cost. For example, this table shows the postal rates for shipping items to the U.K. (United Kingdom) in 2023:

Mail ClassRate
Priority Mail Express International Flat RateStarts at $65.95
First‑Class Package International ServiceStarts at $16.96
Priority Mail International Flat RateStarts at $39.19
Global Express GuaranteedStarts at $82.70
Priority Mail InternationalStarts at $57

What Happens if I Don’t Have the Right Amount of Stamps?

Say your package does not have a return address and do not use enough stamps. In that case, the post office will try to collect additional postage from the recipient.

If the recipient refuses to pay the postage, USPS might send the item to “dead letters.” 


  1. How much is the additional ounce stamp? How much is an additional ounce stamp worth?

As shown above, the USPS stamp price increase took effect on July 9, 2023. The new rates reflect a three-cent increase to the rate of a First-Class Mail Forever stamp from 63 cents (¢) to 66 cents. 

These increases raised First-Class Mail prices by approximately 5.4% to counter inflation.

  1. Is the additional ounce stamp a forever stamp?

No. However, the words “Additional Ounce” on this stamp indicate the value of the stamp. Like a Forever Stamp, these stamps remain valid for the rate printed on them.

  1. How much does a postage stamp cost?

The answer to this question depends on what type of mail you want to send. The table below shows the mail rates for different items:

Mail ItemMaximum WeightPost Office Rate


  1. U.S. Postal Service Files Notice with PRC for New Mailing Services Pricing
  2. Postage Stamp Price Increase
  3. International Mailing Services: Proposed Price Changes
  4. Forever Stamp Fact Sheet
  5. U.S. Post Office Seeks to Raise Stamp Prices in January
  6. Price of a Forever stamp is going up. Here’s how much they will cost in January
  7. The Postal Service wants to raise the price of a first-class stamp to 66 cents
  8. Sizes for Large Envelopes and Flats
  9. USPS Shipping to Canada from the US
  10. How to Send a Letter or Postcard: Domestic
  11. USPS Forever Stamps, First Class Stamp
  12. Postage Stamps – The Basics
  13. USPS® Shipping and Mailing Price Changes
  14. How Much is a Stamp?