Size Standards for Mail Art Mailed From the US

LETTER SIZE STANDARDS

Question: What are the largest and smallest sizes mailable?
Answer: The SMALLEST mailable size is 3 1/2 inches high, 5 inches long and must be rectangular in shape. The LARGEST mailable size is 6 1/8 inches high, 11 1/2 inches long. Any letters weighing 1 oz or less that exceed these standards will incur an 11cent "nonstandard" surcharge. Postage for the first ounce is 33 cents, 22 cents for each additional ounce.

POSTCARD SIZE STANDARDS

Question: What is the smallest and largest size mailable?
Answer: The SMALLEST mailable size is 3 1/2 inches high, 5 inches long and must be rectangular in shape. The LARGEST mailable size is 4 1/4 inches high, 6 inches long. Postcards exceeding these dimensions are charged the letter rate of 33 cents. The postage rate for a postcard is 20 cents.

From the USPS Consumer Guide to Products & Services - 9/12/99

Minimum Size Standards

Pieces 1/4 inch or less thick are mailable if they are rectangular and:

At least 3 1/2 inches high.

At least 5 inches long (items sent to foreign countries must be at least 5 1/2 inches long).

At least 0.007 inch thick (about the thickness of a postcard).

Mail not meeting these standards is returned to the sender.

Nonstandard Size Mail

Nonstandard size mail is more costly to handle because it usually cannot be mechanically processed. First-Class Mail and international letters are nonstandard if they weigh 1 ounce or less and they exceed any of these size limits:

Height exceeds 6 1/8 inches, or

Length exceeds 11 1/2 inches, or

Thickness exceeds 1/4 inch, or

Length divided by height is less than 1.3 or more than 2.5 inches.

A surcharge, in addition to the applicable postage and fees, is applied to each piece of nonstandard size mail for two reasons: it compensates the Postal Service for the added cost of manually handling nonstandard mail, and it promotes the design and use of mail that can be processed mechanically.

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