Business envelopes, also known as commercial envelopes, are characteristically open side style with diagonal seams. #11 Business envelopes measure 4-1/2" x 10-3/8" and are come in a range of paper stocks, colors, weights, flap and seal types.

While historically the smaller sized envelopes were known as commercials and sizes 7 through 14 were called officials, the Envelope Supplies Shop uses the term business envelopes for all sizes.