How many stamps for a 1.25 oz. letter?

To mail a 1.25 oz. letter within the United States, you typically need to use the current First-Class postage rates. As of my last update, a standard First-Class stamp covers up to 1 oz. For each additional ounce, you need to add extra postage, often requiring an additional stamp or a specific ounce surcharge. It's best to check the USPS website for the most current rates and requirements.