Typically speaking, using regular notebook paper and a single envelope, 4 to 5 sheets of paper can be mailed while staying under 1 ounce. The United States Postal Service charges one stamp per ounce for letters. Using heavier paper or a thicker envelope will result in a much higher weight, which means less sheets of paper can be mailed using only one stamp.
When using the USPS, it is important to know the weight of the parcel being shipped so that an individual knows how much he or she will have to pay. If it is possible to condense a letter into a few less sentences, an individual might be able to cut their shipping price in half. It is also important to note that the weight of a parcel includes the weight of the packaging, not just the contents within the package.
A single sheet of 8 1/2-inch by 11-inch notebook paper weighs roughly .16 ounces. An envelope weighs slightly less than that. This means that four pieces of notebook paper and an envelope can be comfortably mailed using only one stamp, and five sheets of paper may even still stay under the 1-ounce limit. Using printer paper or a thicker envelope means that the number of sheets being mailed must be less than four.