How to Mail a Letter in the U.S. with USPS (Domestic & International)

• 27 min read

Mailing a letter through the United States Postal Service (USPS) is simple if you follow the right steps. This guide walks you through everything from addressing the envelope to choosing postage, mailing options, and extra services for both domestic and international letters.

1. Addressing an Envelope Correctly

Proper addressing ensures your letter reaches the right destination. We have detailed instructions here. Or follow the step-by-step instructions for formatting the addresses below:

  1. Sender’s Address (Return Address) – Write your address in the top-left corner of the envelope. Include your full name (or company name), street address and apartment/suite if applicable, and city, state, ZIP code (use the 5-digit ZIP or ZIP+4 if you know it) on separate lines. This tells USPS where to return the mail if delivery isn’t possible.

  2. Recipient’s Address (Delivery Address) – Write the recipient’s address in the center of the envelope (a bit toward the bottom). Include the recipient’s full name, street address and unit number, and the city, state, and ZIP code on separate lines.

  3. Use Clear Formatting – Print clearly in dark ink and capital letters for readability by USPS scanners. It’s recommended to avoid commas or periods in the address and use the official two-letter state abbreviations (for example, use “CA” for California). Neat, legible addresses help your letter arrive faster.

  4. International Addresses – If sending abroad, include the destination country on the last line of the recipient’s address (in English and all capitals). For example: “LONDON, W1A 1AA UNITED KINGDOM.” For your return address, add “USA” on the last line so foreign postal services know the letter came from the U.S.. It’s also helpful to write “AIR MAIL/PAR AVION” on the envelope to indicate it should go by airmail. (Most international mail travels by air, but this label is a traditional practice.)

  5. Double-Check Details – Make sure names are spelled correctly, address numbers are accurate, and ZIP codes match the city. A complete and correct address prevents delays. Once addressed, insert your letter, then close and seal the envelope securely (use the envelope’s glue or tape). Now you’re ready to add postage.

2. Determining Postage and Payment Methods

Before mailing, you need to pay for postage – the cost to send the letter. Here’s how to determine the right postage and ways to pay:

  • Calculate Postage by Weight & Size: Postage for letters is mainly based on weight and dimensions. A standard First-Class letter stamp covers up to 1 oz (about 4 sheets of paper in a regular envelope). Weigh your letter on a kitchen scale or at the post office to see if it exceeds 1 oz. If it’s over 1 oz (or if you use a larger envelope), you’ll need additional postage. For instance, each extra ounce (up to 3.5 oz for letters) costs an additional fee (currently $0.28 per extra ounce for domestic letters). Non-standard shapes (like square or rigid envelopes) also incur a “non-machinable” surcharge (about $0.46 extra) because they can’t go through sorting machines.

  • Use the Correct Stamp: For a normal domestic letter, you’ll likely use a First-Class Mail Forever® stamp. A Forever stamp is valid for the current 1 oz letter rate, no matter when you bought it. As of 2024, one Forever stamp costs $0.73 (the costs have not been raised in 2025) and covers 1 oz in the U.S.. If your letter needs more postage (due to weight or size), you can combine stamps to add up to the required amount  (e.g. two Forever stamps for a 2 oz letter). There are also specific stamps for postcards, international letters, etc. (a standard postcard stamp is $0.56, and an international Global Forever stamp is $1.65 – more on international postage below).

  • Where to Buy Stamps: Stamps can be purchased at any post office or at many grocery stores, pharmacies, and other retailers. You can also buy them online from the USPS Postal Store. If you have a lot of mail, you might use a postage meter or online postage service to print your own postage, but for a simple letter, an ordinary stamp is easiest. We have an article on all the places where you can by a stamp.

  • Online Postage & Payment: For certain mail services (like Priority Mail or international packages), USPS offers Click-N-Ship® to pay postage and print labels online. However, for a basic letter, you typically don’t print postage online (unless using a service like Stamps.com). The simplest method is to apply the appropriate stamps. Tip: Put the stamp on last, after addressing, so you don’t waste it if you need to correct anything on the envelope.

  • International Postage: Mailing a letter overseas costs more. A Global Forever stamp is used for a 1 oz letter to any country and currently costs $1.65. This single stamp will send a 1 oz letter or postcard anywhere in the world. If your international letter weighs over 1 oz, you’ll need additional postage based on the country – rates vary by country “price group,” which you can find via the USPS International Price Calculator . For example, a 2 oz letter to Europe will cost more than $1.65, so you might attach a Global Forever stamp and additional cent stamps to make up the correct amount. A larger envelope (flat) internationally starts at $3.15 for 1 oz . If you’re unsure, a USPS clerk can weigh your international letter and tell you the exact postage needed.

Payment Methods: For a simple letter, stamps are the easiest payment. Each stamp has a value that covers the postage. If you go to the post office, you can pay cash/card for the postage and they will postmark or meter the envelope instead of using stamps. Businesses or frequent mailers might use postage meters, but that’s beyond the scope of a single letter. In summary: use a stamp or stamps equal to the required postage, or pay at the post office counter where they can print a postage label for your letter.

3. USPS Mailing Options (Domestic Services)

USPS offers several mailing classes or services for domestic mail. The right choice depends on how fast you want delivery and what you’re sending. Here are the common options for mailing letters or packages within the U.S.:

  • First-Class Mail® – This is the standard service for mailing letters, cards, and small lightweight packages. It’s affordable and usually delivers in 1–5 business days locally or nationwide . A normal letter you send with a Forever stamp goes First-Class. It’s for envelopes up to 3.5 oz (and large flat envelopes up to 13 oz). Cost: A single-piece letter stamp is $0.73 (one Forever stamp) for the first ounce. Tracking: Not included by default on a plain First-Class letter – once you put a stamp and drop it in the mail, you won’t automatically get a tracking number. However, you can pay for extra services (like Certified Mail) to get proof of delivery if needed (more on that below). First-Class Mail is best for ordinary letters, bills, greeting cards, and other day-to-day mail that doesn’t require special handling.
  • Priority Mail® – This is an expedited service for faster delivery, typically 1–3 business days anywhere in the U.S.. Use Priority Mail when you have a slightly heavier item or just want your mail to arrive quicker than First-Class. Many people use Priority for important documents or small packages. USPS provides free Priority Mail envelopes and boxes , including Flat Rate packaging – if your item fits, it ships for a fixed price regardless of weight (up to 70 lbs). Cost: Starts around $9–$10 for a letter-sized Flat Rate envelope at retail. Tracking: Included for free – every Priority Mail shipment comes with a USPS Tracking number . Insurance: Included up to $50–$100 value by default . Priority Mail is great for mailing time-sensitive letters or valuables that need tracking and a bit of insurance.
  • Priority Mail Express® (formerly Express Mail) – This is the fastest domestic service, with overnight or 1–2 day delivery guaranteed to most locations. If you absolutely need a document delivered by the next day, use Priority Mail Express. It even delivers on weekends and holidays in many areas (often with an extra fee for Sunday/holiday delivery). Cost: It’s much more expensive – starts around $25–$30 for a flat envelope (actual retail starts at $31.40 for a flat-rate envelope). You must use a special Priority Mail Express envelope or label, which the post office provides. Tracking: Always included. Insurance: Comes with up to $100 insurance included (and you can buy more if needed). Priority Mail Express also offers a money-back guarantee – if it’s late, you can get a refund of postage for many shipments. Use this for urgent legal documents, passports, or any letter that absolutely must arrive by a specific deadline.
  • USPS Ground Advantage™ – (Formerly services like Retail Ground and First-Class Package combined) This is primarily for packages, but if you had a very thick or large envelope that doesn’t qualify as letter, you might use Ground. It’s a 2–5 day delivery service by ground transport. Ground is cheaper than Priority for heavy items, but slower. or typical letters, you won’t use Ground Advantage – First-Class is simpler. (Ground Advantage does include tracking by default and accepts items up to 70 lbs) .
  • Media Mail® – A special low-cost service for books, printed materials, CDs, DVDs and other educational media. Delivery is slower (about 2–8 days) and only specific items can be sent at Media Mail rates. Cost: Very cheap – starts around $4 and up, based on weight. Restrictions: You cannot send personal letters or cards via Media Mail – the USPS can actually open and inspect Media Mail to ensure it only contains allowed media . If you include non-media items, the recipient might have to pay extra postage or the mail could be returned. Media Mail is mostly used for sending things like a box of books or educational material. It’s not applicable for a regular letter (unless that letter is a book manuscript or something qualifying).
  • Certified Mail® – Certified Mail is an extra service you can add to First-Class or Priority Mail (it’s not a standalone class) when you need proof of mailing and delivery. When you send a letter via Certified Mail, you get a receipt showing you mailed it, and USPS provides an electronic tracking number. The recipient usually has to sign for it, and you can see online when it was delivered (or if a delivery attempt was made). Certified Mail is often used for important legal or business documents because it records the delivery. For example, if you mail a notice via Certified Mail, you have evidence it was sent and received. Cost: To add Certified Mail to a letter costs about $4 (on top of regular postage). Tracking: Yes, it’s essentially tracked – you can see delivery status. If you also need a physical proof of who signed for it, you can combine Certified Mail with a Return Receipt service to get a signature postcard or PDF emailed to you (details on Return Receipt in section 6). In short, Certified Mail gives you peace of mind that your letter made it, with documented proof.
  • Registered Mail® – Registered Mail is the most secure mail service USPS offers for valuable or irreplaceable items. It travels under tight security, being signed for at each handoff point, and kept in locked containers or safes during transit. This makes it slower than regular mail (because of the special handling), but very secure. You can use Registered Mail for important documents or high-value items (like jewelry, coins, etc., though for items you’d likely also use padded packaging). Insurance: You can insure Registered Mail up to $50,000 value, far higher than other services. Cost: The fee for Registered Mail is additional (around $15 or more, depending on value declared) plus the postage – it’s a premium service. Tracking: Registered Mail is trackable, and recipients often have to sign for it upon delivery (providing proof of delivery). Use Registered Mail when you need maximum security and chain-of-custody for something important – for example, sending legal documents, confidential papers, or valuables that shouldn’t be lost. (Many people don’t use Registered Mail for everyday letters due to the cost and slower delivery, but it’s good to know it exists for special cases.)

Choosing a Service: For a normal letter, First-Class is the default choice. If you need faster delivery or tracking, upgrade to Priority Mail. Use Certified if you need proof of delivery, and Registered for high-security needs. Priority Mail Express is only for the rare cases you need overnight speed. And unless you’re sending qualifying media, Media Mail won’t apply to a regular letter.

4. USPS International Shipping Options

When mailing letters or packages overseas, USPS offers several international services. The options vary by speed, cost, and included features like tracking. Here are the main international mailing options:

  • First-Class Mail International® – This is the most economical way to send letters and lightweight packages internationally. Use First-Class Mail International for letters, postcards, and large envelopes (flats) up to 15.994 oz (letters over that become small packages). Delivery times can range roughly 1 to 3 weeks (6–20 business days) depending on the destination country. Cost: For a 1 oz letter, it’s $1.65 (one Global Forever stamp) to any country. Heavier letters or flats cost more based on weight and country – e.g., a 2 oz letter might be around $2.70, etc. This is airmail postage to anywhere in the world. Tracking: Not included for ordinary letters – once it leaves the U.S., you generally do not get door-to-door tracking with a simple First-Class International letter. (Some countries may scan the customs barcode, but you shouldn’t count on detailed tracking.) If you’re sending a First-Class Package International (a small package up to 4 lbs), USPS does include tracking to many countries , but a flat document envelope won’t have full tracking. When to use: First-Class Mail International is best for letters, documents, or postcards that aren’t extremely time-sensitive. It’s the cheapest way to mail abroad. Just drop it in the mail with the right stamps, and it will get there in a few weeks.
  • Priority Mail International® – This is a faster international service for letters and packages, with typical delivery in 6–10 business days to major destinations. It’s like the international version of domestic Priority Mail. Cost: higher than First-Class – for example, a Priority Mail International Flat Rate Envelope starts around $30 (you can stuff up to 4 lbs in it). Packages can go up to 70 lbs (using your own box by weight-based pricing, starting around $42.95 for a small package) . Tracking: Included – you get a tracking number that works in the destination country too, so you can see delivery confirmation. Insurance: Included up to about $100 for merchandise (and you can purchase more) by default. Priority Mail International is a good option if you have an important document or parcel that needs to arrive in under two weeks and you want tracking.
  • Priority Mail Express International® – A step up in speed, this service delivers in 3–5 business days to many countries. It comes with a date-certain delivery guarantee to select countries or else you get a postage refund. Cost: more expensive; starts around $45–$60 depending on destination and weight . Like domestic Express, you often use special Flat Rate envelopes or boxes for convenience (flat rate boxes can go up to 20 lbs internationally). Tracking: Included, door-to-door. Insurance: About $100 included, and can add more. Use PMEI if your letter or package is urgent and you need it there within a week. It’s a reliable expedited option (often it will actually get there in 3 days).
  • Global Express Guaranteed® (GXG) – This is the fastest international service USPS offers, with 1–3 business day delivery worldwide. GXG is actually a partnership with FedEx Express for international delivery. It offers a money-back guarantee if the item isn’t delivered by the promised date. Cost: very expensive – starting around $70+ even for a document. It’s used for urgent documents or items that absolutely must arrive as fast as possible overseas. Tracking: Always included (extensive tracking). Insurance: $100 included, and you can buy up to the limits allowed for the destination. GXG is overkill for casual letters – it’s typically used by businesses or for critical international shipments given its high cost, but it’s good to know it exists as an option.

Customs Forms: When mailing internationally, remember customs rules. If your envelope contains only documents or correspondence with no merchandise or anything of value (for example just papers, letters, printed documents), you typically do NOT need a customs form. A simple letter to another country can be dropped in the mail with the correct postage just like domestic mail. But if you include anything else (like a small gift, photographs with monetary value, a CD, etc.), you must attach a customs declaration. For letters and small items, that is usually Form PS 2976 (a small green customs sticker) which you can get at the post office or fill out online. Always check the destination country’s restrictions and prohibitions for mail—some items can’t be mailed to certain countries  (for example, some countries don’t allow coins, jewelry, or certain foods). The USPS Index of Countries and Localities lists each country’s rules , but for a normal letter with documents, you won’t have issues.

Summary: For international letters, stick with First-Class Mail International unless you have a deadline. If you need faster delivery or tracking, upgrade to Priority Mail International. Use Express International for rush delivery, and GXG for absolute fastest (and most expensive) service. Be sure to pay the correct postage in international stamps, include the country name in the address, and fill out customs forms if required.

5. Tracking and Insurance with USPS

USPS offers tracking and insurance services to give you peace of mind when mailing valuable or important items. Here’s how they work and how you can use them:

  • USPS Tracking (Delivery Confirmation): Tracking is a service that lets you follow the progress of your mail with a unique tracking number. Most USPS services include tracking automatically – for example, Priority Mail, Priority Mail Express, USPS Ground Advantage, etc. all come with a tracking number at no extra charge. The notable exception is First-Class Mail letters with just a stamp, which do not include tracking. If you send a regular stamped letter, you won’t have a built-in way to see where it is. However, you can add tracking by purchasing an extra service: the most common way is using Certified Mail (as described above, it provides a tracking number and proof of delivery for a fee). For packages, you can also pay for standalone USPS Tracking service on First-Class Package, but for letters the Certified option is the way to go. When you have a tracking number (13- to 22-digit code), you can enter it on the USPS website or mobile app under “Track a Package,” or call USPS, to see the status and final delivery confirmation. You can even sign up for text or email alerts for updates. Delivery Confirmation is essentially the final part of tracking – it will show “Delivered” (often with a date/time and sometimes the location like “Left in Mailbox”) once your item reaches its destination. This is useful if you need to prove a letter was delivered.
  • Insurance: If your mail has monetary value or important contents, consider insurance. Insurance protects against loss or damage by reimbursing you up to the declared value if the item is lost or damaged in transit. Some services include insurance for free: Priority Mail and Priority Mail Express include up to $100 of insurance at no charge . (Priority Mail typically includes $50 for retail customers and $100 for commercial, but USPS often states $100 in general.) If your item is worth more, or you’re using a service that doesn’t include insurance, you can purchase additional insurance. You can buy insurance for First-Class packages or Priority Mail up to $5,000. Registered Mail includes insurance options up to $50,000 as mentioned  – you pay incrementally based on the value. When you insure an item, hang on to the receipt and any proof of value (like appraisals or invoices) in case you need to file a claim. For an average letter (documents), you usually don’t need insurance, but if you’re mailing something like a rare document or a valuable photograph, it might be worth it. To buy insurance, you typically must go to the post office and declare the value when you pay postage (or use an online label service where you can add insurance). International mail: Priority Mail International and Express International include limited insurance (around $100 for documents, $200 for merchandise by default). You can often buy extra insurance for international packages, though some countries have lower limits or restrictions on insured mail.
  • Tracking Internationally: Note that not all international services provide full tracking. Global Express, Priority Mail Express Int’l, and Priority Mail Int’l all include tracking to the destination . First-Class Package Int’l has tracking to many countries , but a First-Class letter with just stamps will only have a customs number that might show limited tracking (or none) – effectively, no guaranteed tracking. If you need confirmation of delivery internationally for a letter, you might opt for Registered Mail International or use Priority Mail Express International which can provide a delivery record. International Return Receipt service is also available if you send something by Registered or Certified (to countries that reciprocate that service).

How to use these services: If you’re mailing at the post office, just tell the clerk you want tracking or insurance on your item. They will suggest the appropriate service (Certified Mail for a letter, or insured mail, etc.). If you’re printing postage online (for Priority Mail, etc.), you’ll have options to add insurance and the tracking number is provided with your label. Always keep your receipt when you buy postage at the counter – it will list your tracking number and insurance details. You can use that receipt to track the item later or to file a claim if needed.

6. Sending the Letter: Drop-Off, Mailboxes, or Pickup

Once your letter is all ready (addressed, stamped, and packed with any extra services), it’s time to send it off. You have a few convenient options to get your letter into the USPS mailstream:

  • Leave in Your Mailbox for Pickup: If you have a residential mailbox, you can simply put the letter in your mailbox and raise the red flag (if you have one). The raised flag signals to your mail carrier that there’s outgoing mail to pick up. On the next delivery day, the carrier will collect your letter. (This works if you have regular mail pickup at your location. If you have a community cluster box, there’s usually an outgoing mail slot where you can drop letters, and the carrier collects from there.)
  • Drop in a Blue Collection Box: Those familiar blue USPS mailboxes on street corners are a convenient way to send letters. Just open the drop slot and toss your letter in. Each box has pickup times listed – the USPS collects mail from them once or multiple times a day. If you drop your letter before the last posted pickup time, it will go out that day. Dropping in a collection box is safe and ideal for typical letters. Note: If your letter is over 10 oz (a very heavy letter or small parcel) and you’ve only used stamps for postage, do not drop it in a street box. USPS rules require heavier stamped mail to be handed to a postal employee. A normal letter won’t exceed this, but if you ever send a big envelope with a lot of stamps, take it to the counter.
  • At the Post Office: You can bring your letter to any post office. If you already have stamps on it, you can hand it to a clerk or drop it in the indoor mail slot or outgoing mail bin in the lobby. If you don’t have postage yet, you can go to the counter, have them weigh your letter, sell you the proper postage, and they will take the letter. Post offices also often have an after-hours lobby slot where you can drop letters even when the counter is closed.
  • Schedule a Pickup: If you can’t leave your house or have a lot of mail, USPS offers a free pickup service. You can schedule a pickup online via the USPS website. If you’re only sending letters, usually you would just leave them for your normal carrier as described. Scheduled pickups are more common when you have a package (USPS will come get your packages from your porch or door on a specified day). The pickup can be free if it’s done during your regular mail delivery. Go to the USPS Schedule a Pickup tool and you can arrange for your mail carrier to come get your outgoing letter or package on a given day. This is especially handy for sending out batches of mail or if you’ve printed postage at home. Just be sure to specify what and where you will leave it (e.g., in mailbox, or at front door). For a single letter, you might not need a special pickup – the normal daily pickup from your mailbox should suffice.
  • Mailing from Work or Other Places: If your workplace has an outgoing mail collection, you can drop your personal stamped letters there too – they typically get picked up with the business mail. Likewise, some apartment buildings have an outgoing mail slot or a designated area for outgoing mail.

No matter which method you choose, make sure your letter is securely in the custody of USPS (mailbox, handed to carrier, official box, or post office drop). If you’re sending something certified or insured and need a receipt, it’s best to do it at the post office counter so you get the mailing receipt with a postmark. For all other regular letters, any of the above drop-off methods will work.

7. Additional Services: Return Receipts and Delivery Confirmation

In addition to tracking and insurance, USPS offers a few extra services that provide confirmation and records of delivery. Two common ones are Return Receipt and Delivery Confirmation/Signature services:

  • Return Receipt – This service provides you with proof of delivery, with the recipient’s signature. It is often used in conjunction with Certified or Registered Mail. There are two forms: the traditional green postcard that is mailed back to you, or an electronic return receipt (an email with a PDF of the signature). When you send a letter with Certified or Registered Mail and add Return Receipt, the postal carrier will obtain the signature of the recipient (or their agent) at delivery, and that signature record is then returned to you as evidence. The green postcard option will have the person sign the card at delivery, and then USPS mails that postcard back to your address – so you physically receive it, showing the date delivered and who signed. The electronic version skips the postcard and instead, you can later download or get emailed the signature info. Cost: a few dollars extra (around $4.10 for a mailed postcard, or $2.62 for an emailed receipt) . Use Return Receipt when you need to prove not just that USPS delivered it, but who received it. For example, legal notices, contract documents, or important items often use Certified Mail with Return Receipt so you have a signed paper trail. To request it, you’ll fill out a small green card (for physical receipt) at the post office or check the option when buying postage online. You’ll receive the proof after delivery: either the card in the mail or an email with the delivery record.
  • Delivery Confirmation & Signature Services – Delivery Confirmation is essentially the basic USPS Tracking that comes with many services, which we covered in section 5. It will tell you when and where an item was delivered (e.g. “Delivered, Front Door” on a certain date). For most package services, this is free and standard. However, if you are mailing something and want a required signature upon delivery (meaning the item won’t be left without a person signing), you have options: Signature Confirmation is an add-on that requires the recipient (or someone at the address) to sign for the package, and you can later see a copy of that signature. This is useful if you want to be sure the item wasn’t just dropped off, but handed to someone. Signature Confirmation costs a few dollars (~$3–$4) and can be added to many services . Note that Certified Mail already requires a signature by default, and Registered Mail always requires a signature, so you wouldn’t add Signature Confirmation on top of those. It’s more for things like if you send a Priority Mail package and really want a signature at delivery (Priority includes tracking but the driver might leave it without knocking if no signature is required). For a letter, if you’re using Certified, that covers the signature requirement, so Signature Confirmation isn’t used on letters generally. In summary, “Delivery Confirmation” usually refers to the confirmation you get from tracking when something is delivered, and “Signature Confirmation” is an extra service ensuring a signature is obtained at delivery (and is another form of delivery confirmation with higher certainty). If you just drop a regular letter with a stamp, you have no delivery confirmation unless you use one of these special services.

Other notable services: Restricted Delivery (ensures only a specific person (addressee) can sign for the mail), which can be combined with Certified or Registered for an extra fee, and Certificate of Mailing, which is a proof of mailing (not delivery) – basically a receipt that you mailed something on a certain date. These are more niche, but available if needed.

Tip: For most personal letters, you won’t need these extras. But if you ever find yourself needing verifiable proof that your letter was sent and received (for legal or important matters), know that Certified Mail with Return Receipt is a common solution. It provides a mailed paper trail: you get a postmarked receipt when you send it, tracking as it’s in transit, and a signed confirmation upon delivery – about as much evidence as one can get of delivery.

In Conclusion: Mailing a letter with USPS involves addressing the envelope properly, using the right postage, and choosing an appropriate service if you have special needs. For a regular letter, it can be as easy as putting on a Forever stamp and dropping it in the mailbox. For important or international mail, take advantage of USPS services like Priority Mail, Certified Mail, or Global stamps to ensure your letter arrives safely and on time. By following the steps above, you’ll have your letter on its way with confidence. Happy mailing!

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