One first-class stamp currently costs $0.66 at the U.S. Post Office for a standard letter up to 1 ounce mailed in 2025; additional ounces and special services cost extra. This guide explains how much postage you need for letters, flats, postcards, and packages, how Forever and non-denomination stamps work, and how to buy stamps in person, online, or in bulk. It also covers when stamps expire, how to add correct postage, and how to avoid returns or extra fees.
Current U.S. Postal Service Prices (2025)
First-Class Mail Letter (1 oz or less)
The price for a single first-class letter (standard letter) up to 1 ounce mailed domestically in 2025 is $0.66. For each additional ounce within the first 3 ounces, the rate increases; you must add the required number of stamps or use equivalent postage such as metered mail. Postcards have a lower rate, and larger letters or flats are priced differently. These prices reflect the most recent announced adjustments and apply to ordinary envelopes and similar items sent within the United States.
Notable Price Points at a Glance
| Mail Type | Weight Limit | Rate (2025) | Notes |
|---|---|---|---|
| First-Class Letter | 1 oz | $0.66 | Forever stamp covers base; add stamps for extra oz |
| Additional Ounce (1–3 oz total) | Each extra oz | $0.24 | Charged per additional ounce within first 3 oz |
| Postcard | 1 card | $0.64 | Must be rectangular, specific size |
| First-Class Flat (large envelope) | 1 oz | $1.32 | Higher due to size and bulk |
| Priority Mail (1 lb package) | 1 lb | $9.95–$10.95 | Varies by zone and speed |
Types of Stamps and How They Work
Forever Stamps
Forever stamps remain valid for first-class letters regardless of future price increases. If you buy a Forever stamp at the current $0.66 rate, you can use it later even if the price rises to, for example, $0.68 or more, as long as it covers the then-current first-ounce rate. You may combine Forever stamps with additional stamps to reach the correct total. The value of a Forever stamp is tied to the First-Class Letter price and changes whenever the Postal Service updates that rate.
Non-Denominated (No-Value) Stamps
Non-denomination stamps display a purpose such as "First-Class" without a numeric value. They are valid for the indicated service at the time of use, but if prices increase, you may need to add more postage to reach the new rate. Unlike Forever stamps, non-denominated stamps do not automatically adjust in value. Businesses using automated systems often prefer metered postage to avoid handling numerous low-value stamps.
How to Calculate the Correct Postage
To determine how much postage you need, first identify the mail class (First-Class, Priority, Standard Post), then find the weight and dimensions. For letters, count the ounces beyond the first: the first ounce costs the base rate, and each additional ounce (up to 3 oz) adds a set amount. For flats and packages, use the price tiers for your destination zone and service level. Metered mail can calculate exact postage based on weight and destination, reducing the need for many stamps. When in doubt, check the USPS official price calculator or visit a post office clerk for guidance.
Where to Buy Stamps
- U.S. Post Office locations and retail partners such as grocery stores and pharmacies.
- Online through the USPS official website with delivery to your address.
- Vending machines at select locations that sell booklets and rolls.
- Postal Service.com or authorized sellers for bulk purchases, often at slight discounts.
Many people ask how much postage per stamp when buying in sheets or rolls; the per-stamp cost is typically the same, but bulk options can simplify mailing for businesses. You can also add stamps to existing mail for additional weight, but it is usually more convenient to use the correct number of stamps at the time of preparation.
Rules About Expiration and Validity
The United States does not formally expire Forever stamps or previously issued stamps with valid state-specific designs, as long as they are legible and not altered. Older definitive stamps without denomination may not be accepted at the current first-class rate; in such cases, you must supplement postage to cover the difference. Damaged or difficult-to-read stamps may be refused, so keep them clean and store them safely. Metered postage and online postage purchases are valid indefinitely if used according to service rules.
Common Situations and How to Avoid Extra Fees
- Use a scale to weigh letters and packages; underestimating weight is a frequent cause of underpaying.
- Check size limits: flats and parcels have specific dimensional thresholds that change pricing.
- For international mail, choose the proper service (e.g., Priority Mail International) and include customs forms.
- Add postage promptly if your letter is returned for insufficient funds; the sender typically must cover the original charge plus the return fee.
Correct postage prevents delays and extra fees, ensuring your items reach recipients on time. By understanding the cost per stamp, the value of Forever stamps, and the right mail class for each item, you can handle mailing confidently and accurately.