What is a #10 business envelope? Envelopes in this size have a standard height of 4 1/8 inches by a length of 9 1/2 inches. A standard 8 1/2 x 11-inch piece of paper can easily be held in them, which ...

What size envelope should be used to mail a standard size business letter? The most common type of business envelope is the regular envelope. A popular #10 envelope measuring 4 1/8" by 9 1/2" is ...