You may not think much of an envelope, but it can play a big part of your sales letter success. Envelope design needs to be well thought out to be effective. Know what it takes to get your mail noticed and letters opened.

This sample business letter envelope includes formal components, some of which are optional for typical, employment-related business letters.

The graphic below represents the US Postal Service automation guidelines for a standard business envelope that is 4-1/8 x 9-1/2 inches.

Letters, bills, greeting cards, and other documents can be sent in standard white, manila, or recycled paper envelopes. Items needing extra protection can be sent in bubble-lined, padded paper, or waterproof envelopes. These envelopes, along with stationery and prepaid First-Class Mail postcards and envelopes, can be purchased at the Post Office.

Standard sizes (dimensions in inches) for correspondence and announcements envelopes.

Use these rulers and guide boxes to measure letters and large envelopes.

Once a piece of mail exceeds the maximum length, height, or thickness of one shape, it automatically gets classified as the next largest shape.