What Size Are #10 Envelopes - 6 inches by 12 inches. 5 inches by 11.5 inches. Web simply put, the standard #10 envelope size is an envelope with sides that measure 4.125x9.5. Regular envelopes have standard envelope sizes similar to those you often use for most. This size is perfect for mailing. 10 regular is the most common envelope size (bills and other business correspondence are typically sent using. Web people use the popular #10 envelope size to send all types of business correspondence, such as letters, documents, checks, and.
6 inches by 12 inches. Regular envelopes have standard envelope sizes similar to those you often use for most. 5 inches by 11.5 inches. 10 regular is the most common envelope size (bills and other business correspondence are typically sent using. Web people use the popular #10 envelope size to send all types of business correspondence, such as letters, documents, checks, and. Web simply put, the standard #10 envelope size is an envelope with sides that measure 4.125x9.5. This size is perfect for mailing.