What Is the Cost of Mailing a Letter?

Understanding the cost of mailing a letter is essential for ensuring correspondence reaches its destination. Postage fees support the mail delivery network, covering transportation, sorting, and final delivery. Awareness of these costs helps individuals and businesses budget effectively and avoid delays or returned mail due to insufficient postage.

Cost for Standard Letters

A standard First-Class letter must be rectangular, at least 3.5 inches high by 5 inches long by 0.007 inch thick, and no more than 6 1/8 inches high by 11 1/2 inches long by 1/4 inch thick. These dimensions ensure efficient processing by automated postal equipment. The maximum weight for a standard letter at the base First-Class rate is 3.5 ounces.

As of July 13, 2025, a First-Class Mail Forever stamp costs $0.78 for a 1-ounce letter. Forever stamps remain valid for mailing a 1-ounce First-Class letter even if postage rates increase.

Factors Influencing Postage

The cost of mailing a letter can increase beyond the standard stamp price due to mailpiece characteristics and desired services. Weight is a primary factor. For First-Class Mail, a standard letter weighing up to 1 ounce costs $0.78. For each additional ounce, a $0.29 charge applies. Heavier letters require more than a single Forever stamp.

Dimensions and shape also determine postage. Letters that are unusually shaped, rigid, square, or exceed standard dimensions may incur a non-machinable surcharge. This $0.44 surcharge covers extra manual handling, as these items cannot be processed by automated machinery. Larger envelopes, or “flats,” have different pricing and dimension limits, typically for items greater than 6-1/8 inches high, 11-1/2 inches long, or 1/4 inch thick, and can weigh up to 13 ounces.

Destination also impacts cost. Domestic mail is priced differently from international mail. Sending a 1-ounce letter internationally, for instance, costs $1.70 as of July 13, 2025. International rates vary by country and service type, often requiring a Global Forever stamp or specific international postage.

Special mail services add to the base postage cost. Services like Certified Mail, which provides proof of mailing and delivery, carry an additional fee. As of July 13, 2025, the base fee for Certified Mail is $5.30. Adding a Return Receipt, either physical or electronic, incurs further charges, such as $4.40 for a retail Return Receipt (Green Card) or $2.82 for an electronic Return Receipt.

Determining and Applying Correct Postage

Accurately determining the necessary postage for a letter involves assessing its physical characteristics and desired services. This ensures the mailpiece reaches its destination without delay or additional charges.

Begin by measuring the letter’s dimensions and weight. Use a ruler to check the length, height, and thickness, comparing them against standard letter size limits. A kitchen scale can provide an accurate weight in ounces; most standard letters weigh under 1 ounce, but heavier contents or multiple pages can push it over. If the letter is rigid, square, or has lumpy contents, it may be subject to a non-machinable surcharge, regardless of weight.

After determining the letter’s characteristics, calculate the precise postage. The United States Postal Service (USPS) website offers online postage calculators that account for weight, dimensions, destination, and any special services. Alternatively, a postal clerk at any post office can accurately weigh and measure your letter and advise on the exact postage required. This step helps avoid underpayment, which can lead to delayed delivery or the recipient owing postage.

Once the correct postage amount is known, apply the stamps or use a postage meter. Affix stamps neatly in the upper right-hand corner of the envelope. If multiple stamps are needed, place them without overlapping to ensure they can be properly canceled. For businesses or frequent mailers, a postage meter can print the exact postage required directly onto the envelope, which can offer a slight discount compared to retail stamp prices.

Sending Your Letter

After applying the correct postage, the final step is to send your letter. Various convenient options are available for mailing, depending on your preference and urgency.

Stamps can be purchased from numerous locations beyond just post offices. Many grocery stores, pharmacies, and large retail chains also sell Forever stamps. For those needing stamps outside of business hours, self-service kiosks are available in the lobbies of many post offices, providing 24/7 access. Online purchases are also an option through the USPS website, with stamps delivered directly to your address.

Letters can be mailed by dropping them into a blue collection box, which are widely available in communities. For larger or more sensitive mail, taking the letter directly to a post office allows for hand-off to a postal employee and access to additional services. Some areas may also offer mail pickup services, where carriers collect mail directly from your home or business.

For First-Class Mail, typical delivery times within the contiguous United States range from one to five business days. Shorter distances generally result in quicker delivery, often within one to three days, while longer distances may take up to five days. Factors such as weather conditions or operational issues can occasionally extend these estimated delivery times.