We have postal experts on staff who have completed United States Postal Service training so we can get you the lowest postal rates around. We sort, tag, bag and palletize your mail cheaper than the post office can and you can pocket your savings. There are many factors to consider when designing mail. A wealth of information can be found at www.usps.com or email us at info@accuratemailings.com and we will help you design a package that accomplishes your goals. To receive our weekly "Useful Mailing and Post Office Information" email newsletter, click here and send us your email address. Postal Compliance Verification In order to qualify for barcode discounts, all addresses must be updated within 180 days before mailing using a USPS approved address update tool (e.g., Address Correction Service, National Change of Address, FASTforward , or ancillary service endorsement). If Accurate Mailings has provided you with any of these services, we will maintain a record. If Accurate Mailings did NOT provide this service, please fill out and return this certificate so that we can maintain complete and accurate records. Dimensions in Inches Minimum postcard 3.5 x 5.5 Maximum postcard 4.25 x 6.25 Minimum letter 3.5 x 5.0 Maximum letter 6.125 x 11.5 x .25 thick Minimum flat must exceed one of the letter dimensions Maximum flat dimensions 12 x 15 x .75 thick First Class Mail Bills, business transactions and personal letters must be mailed first class. Weight Up to 13 ounces (over 13 ounces mails Priority Mail) Postcards Minimum size 5 inches long by 3.5 inches tall Maximum size 6 inches long to 4.25 inches tall Letters Maximum size 11.5 inches long by 6.125 inches tall by .25 inches thick* 500 piece minimum to qualify for presort rates * nonstandard surcharge may apply Standard Class Mail Promotional mail and impersonal messages Weight Up to one pound Postcards There is no special category for postcards using standard class. In most cases it is cheaper and faster to send postcards first class. Letters Maximum size 11.5 inches long by 6.125 inches tall by .25 inches thick* 200 piece minimum to qualify or presort rates * nonstandard surcharge may apply Official USPS Standards Click on any of the following links to view or download official USPS standards documents in .pdf format (Adobe Acrobat Reader required, click here to download.) Addressing Ancillary Service Endorsements Designing Flats for Automated Processing Designing Letters and Cards for Automatic Processing Postage Rates Tabs and Wafer Seals