What is a #10 Envelope?
Most envelopes that travel through the mailstream are #10s. Monthly statements, monthly bills, and utility bills (commonly referred to as “transactional” mail) are frequently mailed in number 10 envelopes. Direct mail and policy renewals from insurance companies will often use a #10 as well. Fold up an 8-1/2 by 11-inch sheet of paper and you will see that a #10 envelope is its perfect home.