Forever Stamp Weight Limit: Meaning & Requirements For Letters Of Different Weight

If you mail letters or documents regularly, you must have heard of the term “Forever Stamp.” These are (standard letter) stamps with one unique feature – they remain valid for mailing letters or documents regardless of postage price. However, there is a weight limit. 

The weight limit for a forever stamp is one ounce per First Class Mail. Therefore, before using this stamp, it is important to weigh or know the size of your mail. 

This guide explains what a Forever Stamp is and its weight limit. You will also find out what works for letters of different weights and tips that can help you maximize the use of a Forever Stamp. 

What is a Forever Stamp? 


A forever stamp is a postage issued by the United States Postal Service (USPS). The stamp features the word “Forever” and an image of a liberty bell, which signifies that the stamp will remain valid indefinitely. 

Its validity is also immune to future rate increases for postage. This means if you buy a Forever Stamp today at the current rate, you can use it even if the cost of postage increases in the future. There is no need to add an extra postage stamp to make up for the change in rate. 

Forever Stamp Weight Limit 

The Forever Stamp weight limit for a standard letter is one ounce. This means you can use one Forever Stamp to mail a standard weighing up to one ounce. 

If the weight of the letter exceeds one ounce, you will need to affix additional postage or Forever Stamps according to the current postage rate. 

You can find the postage rates for different types of mail and weights on the USPS website. You can also use the postage calculator to determine the appropriate postage for mailing a standard letter.

What Happens If You Use a Forever Stamp on an Overweight Letter? 

If you use a Forever Stamp on an overweight letter, the letter will be returned to you (the sender) with an instruction to include extra Forever Stamps according to the current postage rates. 

Here is a breakdown of what works for letters of different weights: 

  • 1 ounce ($0.63) – 1 Forever Stamp ($0.63)
  • 2 ounces ($0.87) – 1 Forever Stamp + one 24¢ additional ounce stamp ($0.87), or you can overpay by using two Domestic Forever stamps ($1.26)
  • 3 ounces ($1.11) – 1 Forever Stamp + one Postcard stamp ($1.11), or you can overpay by using two Domestic Forever stamps ($1.26)
  • 3.5 ounces ($1.35) – 2 Forever Stamps + one 5¢ stamp + two 2¢ stamps ($1.35), or you can overpay by $0.54 using three Domestic Forever stamps ($1.89)

You should also note that overweight letters take longer to be delivered than standard letters. Therefore, ensuring they are submitted to USPS with the correct postage can prevent unnecessary delays. 

Tips For Using Forever Stamps 

  1. Always double-check the weight of your letter before dispatching it. This helps you confirm that you have included the correct number of postage or Forever Stamp. 
  2. If you plan to mail numerous letters, consider using USPS’s Bulk Mail Services to save time and money. 
  3. If you plan to mail a heavy item like a book, it is important to use a Postal Scale and visit the USPS website to determine the appropriate postage price. 
  4. Always remember that Forever Stamps cannot be used to mail packages or flats with different weight and postage requirements. 
  5. Keep your Forever Stamp in a safe and secure location, as they are valid against any future rate increases and may become very valuable over time. 


Do stamps expire?

Stamps do not expire. You can use them for as long as you want. 

Can stamps be reused?

It is illegal to remove and affix a used stamp on another document. Anyone caught or guilty of this act will face the appropriate penalty. 

Can you send a letter without a stamp?

You can send a letter without a stamp via USPS or other post offices. The recipient will be responsible for the postage fee if such a letter does not feature a return address. 


A Forever Stamp is a USPS stamp with indefinite validity. One Forever Stamp or postage can mail a standard letter weighing one ounce. For letters weighing more than one ounce, additional postage is necessary. 

Understanding this concept and using the correct postage for letters plays a significant time in the timely and efficient delivery. However, not every item passing through USPS can have this postage. 

Examples include packages or flat (such as magazines), which do not belong in the category of standard letters. Additionally, if you are mailing numerous letters, opt for USPS Bulk Mail Service instead of paying per Forever Stamp. 

I hope you found this guide helpful. You should also check out if you can reuse a stamp

Thanks for reading.