Wednesday, July 13, 2016
Q&A: I’m planning a direct mail campaign. Will the envelope size affect the postage rate?
The USPS divides mail into four basic categories: cards, letters, large envelopes (called flats), and packages. Envelopes are usually in the letter or large envelope category. Mailing houses, and the USPS, call large envelopes flats.
The best postage rate for presorted bulk mail (either first class or standard mail), is letter size mail. In this category, the envelope must be rectangular in shape – that is, the length must be greater than the width, and the address block must be parallel to the length. The envelope dimensions can range from 5” to 11.5” in length and from 3.5” to 6.125” in width. The aspect ratio – the length divided by the height – must always be between 1.3 and 2.5. If it is not, the USPS considers this non-standard and will add additional postage. One example is square envelopes which always have an aspect ratio of 1 and require more postage than a standard envelope.
Finally, the envelope with all its contents cannot exceed ¼” in thickness and must be flexible enough to make the turns in USPS high speed mail processing equipment. Of course, you are free to design and use any size and shape of envelope you feel is needed for your direct mail campaign. Just be aware of the postage costs for non-standard envelopes. It may be much higher than you expect. Another example of non-standard envelopes costing more is envelopes in dark colors. Dark colors, especially those without much contrast between addresses, postal indicia and the rest of the envelope, may not be readable by automated USPS equipment. They can still be mailed, but require processing by hand, so the postage cost is higher.