What Is a Self-Addressed Stamped Envelope and How Do You Write It?
A self-addressed stamped envelope (SASE) is an envelope you address to yourself and prepay so someone else can mail a reply back to you. To make one, put your name and address in the center, affix enough postage in the upper right, leave it unsealed, and tuck it into a separately addressed and stamped outer envelope.
If you're sending a form to a club, asking for an autograph, or requesting a paper response, those two envelopes can be easy to mix up. Here's a simple way to get both trips right.
What Is a Self-Addressed Stamped Envelope?
A self-addressed stamped envelope pays for the return trip before the recipient writes back. You send it inside an outer envelope. The person who receives your request puts their response in your prepared envelope, seals it, and mails it to the address you've already written.
USPS itself asks customers for a SASE in some mail-in requests, so this is an ordinary return-mail method, not a special USPS service. It does not include tracking or guarantee a response. The other person still needs to put your item inside and mail it.
Think of the two envelopes as two separate letters: the outer envelope travels to the person or organization, while the inner SASE travels back to you. Each needs its own correct postage.
How to Address a Stamped Envelope
Before you write, check the recipient's instructions. They may specify an envelope size, a department name, or what you need to include with your request.
Write the inner SASE to yourself
On the front of the inner envelope, write your name and full mailing address in the center. Include your apartment or unit number and ZIP Code if applicable. Place the return-trip stamp in the upper right. Do not seal this envelope; the recipient needs to insert the reply.
INNER ENVELOPE — the reply to you
[CORRECT RETURN POSTAGE]
YOUR FULL NAME
YOUR STREET ADDRESS, APT/UNIT IF ANY
YOUR CITY, STATE ZIP CODE
The upper-left corner is for the sender's return address, if the person mailing the reply adds one. You can leave that space open when you prepare a routine domestic SASE. Your own address belongs in the delivery-address area in the center, where USPS says to put the recipient's address. A return address helps undeliverable mail get back to its sender, and some mail types require one. See USPS's addressing guide for the placement rules.
Address the outer envelope separately
The outer envelope has the organization or person's address in the center, your address in the upper left, and its own stamp in the upper right. Put your request and the unsealed SASE inside, then seal only the outer envelope.
OUTER ENVELOPE — your request to them
YOUR NAME [CORRECT OUTBOUND POSTAGE]
YOUR RETURN ADDRESS
RECIPIENT NAME OR DEPARTMENT
RECIPIENT STREET OR PO BOX
RECIPIENT CITY, STATE ZIP CODE
If the SASE must carry a full-size document back without folding, choose a return envelope that fits that document. Make sure the inner envelope itself fits inside your outer mailing envelope, or use a larger outer envelope. A pre-stamped reply envelope that's too small for the expected item won't help the recipient send it.
How Much Postage for a Stamped Envelope?
Postage depends on the finished mailpiece, so check the outbound envelope and return SASE separately. The outer envelope's weight includes your request and the empty SASE. The return envelope's future weight includes whatever the recipient will put inside.
For a standard domestic First-Class Mail letter at the USPS retail rates effective July 12, 2026, up to 1 ounce costs $0.82 and up to 2 ounces costs $1.11. A Forever stamp covers a qualifying 1-ounce domestic letter; a 2-ounce stamp covers a qualifying 2-ounce letter. A large envelope or a square, rigid, or otherwise nonmachinable letter may need a different amount. Check the USPS price list before mailing if you're close to a size or weight limit.
Here's a useful test: place a copy of the expected reply in the inner envelope, seal it temporarily without damaging it, and weigh the sample. If someone will return several pages, don't assume the stamp you use for your short outbound note will also cover the heavier reply. You can browse the site's First-Class stamp collection for everyday letter postage or its two-ounce stamp collection when the finished return letter qualifies for the higher weight tier.
If the return envelope is square, unusually thick, or rigid, ask USPS to classify it before you attach postage. The site's nonmachinable stamp guide explains why a one-ounce letter may need more than a standard Forever stamp.
Mailing Your Self-Addressed Envelope
Slip the unsealed SASE behind your letter or form so the recipient can spot it. If their directions ask for an order number, autograph card, or another item, include that too. Then check the address and postage on each envelope one last time.
I like to read the two center addresses aloud: their address on the outer envelope; my address on the inner one. That quick check catches the most frustrating SASE mistake before it reaches the mailbox.
For a return mailed from another country, don't assume a U.S. stamp on the inner envelope will pay for a letter posted there. USPS Global Forever postage is for mail sent from the United States to an eligible foreign destination. Ask the recipient what return method and postage from their country they accept. If the return needs tracking, a standard stamped SASE may not meet your needs; agree on a suitable service first.
Self-Addressed Stamped Envelope Mistakes
The most common mix-up is putting the organization's address on both envelopes. The inner SASE should point back to you. A second mistake is placing only one stamp on the outer envelope and forgetting that the recipient also needs prepaid postage for the reply.
Don't seal the inner envelope, and don't guess its postage from its empty weight. The response may make it heavier or change its mailpiece category. When the intended reply is valuable, bulky, or time-sensitive, check with the recipient before relying on a regular stamped return envelope.
Self-Addressed Stamped Envelope FAQs
Where does my address go on a SASE?
Put your name and delivery address in the center of the inner envelope. That tells USPS where the reply should go.
Do I stamp both envelopes?
Yes. The outer envelope needs postage to reach the recipient, and the inner SASE needs its own postage for the trip back to you.
Should I seal the return envelope?
No. Leave the SASE open so the recipient can insert the reply and seal it before mailing.
Can I use a Forever stamp?
Yes, for a qualifying domestic First-Class letter weighing no more than 1 ounce. A heavier or nonmachinable reply may need additional or different postage.
Can I send a SASE overseas?
You can send a prepared return envelope, but U.S. postage is not the answer for a reply mailed from a foreign country. Ask the recipient which local return-postage method they accept.
Ready to mail? Lay the envelopes side by side, check that the addresses point in opposite directions, and weigh each finished trip. If both are qualifying one-ounce domestic letters, the site's 2026 U.S. Flags Forever stamps are one option for both trips.