See How Many Stamps You Need For A 9×12 Envelope & The Best Way To Mail It

Envelopes and stamps are fundamental materials to ship mail within and outside the U.S. or any country. But how many stamps do you need to ship a 9×12 envelope? 

You need about two stamps for every ounce to ship a 9×12 envelope. These large envelopes are the right option for flat items that cannot fit into smaller (standard) envelopes and do not require a box. 

Discover how much it costs to mail a 9×12 envelope and the best way to mail your parcel to USPS.

How Many Stamps for a 9×12 Envelope


You need two postage stamps for a 9×12 envelope weighing one ounce or less. USPS First Class or Forever Stamp costs about $1.35 per ounce for large envelopes. 

You must buy an extra stamp if your parcel weighs more than one ounce. An additional stamp costs $0.24 (per ounce), and you can buy as many as your package requires. 

This means you need: 

  • $2.70 worth of stamps to mail a 9×12 envelope weighing two ounces
  • $5.40 worth of stamps to mail a 9×12 envelope weighing four ounces
  • $10.80 worth of stamps to mail a 9×12 envelope weighing 8 ounces

You can also use the postage scale and postage calculator to know the weight of your mail and how many stamps you need. 

What is the Best Way to Mail a 9×12 Envelope? 

The best way to mail any envelope is to drop it off at the post office. This way, your parcel is less prone to theft or misplacement. However, if your home or office is far from the post office, you can place the envelope in your mailbox. 

Once the mail collector arrives, they will pick it up and deliver it to the post office. Lastly, you may need to schedule a pickup for vital or urgent documents. 


What can you mail in a 9×12 envelope?

Books, DVDs, manuscripts, video games, photographs, and artworks. Also, ensure you provide enough cushion for fragile items. 

Does Priority Mail require a signature?

USPS Priority mail shipments may require signature confirmation or not. The shipper and the package type are factors worth considering for this action. 

What are the rules for mailing an envelope?

The stamp must appear in the top-right corner of your envelope, while the destination address must be at the center. Also, ensure you include the appropriate number of postage. 

Can you use the same stamp twice?

It is illegal and punishable in many countries, including the United States. 

What makes a stamp invalid?

A stamp will be considered invalid if: 

  • The iridescent overprint (the shiny character over the stamp) is dull. 
  • The surface is damaged or coarse. 
  • Traces of envelopes are attached to it. 
  • There are faint cancellation marks across the stamp’s surface. 

In a Nutshell 

How many stamps you need for a 9×12 envelope generally depends on the parcel’s weight and the mailing option. However, since most people ship mail via First Class, the standard for one ounce is two stamps ($2.70). 

Anything above an ounce will require extra postage ($0.24) per additional ounce. On the other hand, the cost of stamps is a little different for mailing services such as Priority Mail or Priority Mail Medium. 

This is primarily because these services deliver mail faster than First Class. Their stamps cost a minimum of $9.35.

I hope you found this guide helpful. If you did, please see why you cannot reuse a stamp

Thanks for reading.