First Class Mail

first class mail

For first class letters and flats to be picked up or delivered to Mail Services they should be prepared as follows:


Letter size mail, we ask that if they are not sealed, have the flaps raised up or down. Our mailing machines will seal and apply the postage when processed. We ask that the department seal all flats and invitation size envelopes.

Post Card Dimensions

Minimum size 3.5” (height) x 5” (length) and 0.0007” in thickness. Maximum size 4.25” (height) x 6” (length) and 0.016” thick.

Letter Dimensions

No less than 3.5” (height) x 5” (length) and 0.0009” thick if pieces more than 4.25” high to 6” long. Not more than 6.125” (height) and 11.5” (length) and no more than a .25” thick. Generally no more than 3.3 oz. in weight.

Flats Dimensions

No less than 6.125” (height) and 11.5” (length) .25” thick. No more than 12” (height) and 15” (length) and .75” thick. Maximum weight 13 ozs. Anything over 13 ozs. is Priority Mail. If using staples to seal a flat envelope, we ask that the staples be covered with clear carton sealing tape, or any tape acceptable by the USPS. NO MASKING TAPE


Must be rectangular in shape - a mail piece with the same dimensions in height and length will be charged a surcharge. A letter size mail piece containing any type of object causing it to be un-machineable such as a pencil will also have a surcharge.

Insertion of materials

When stuffing your envelopes please make sure the contents are not sticking up in the flap area or over stuffed. This causes the mail piece not to be securely sealed and will cause problems processing through the mailing machine. A mail piece in a #10 envelope weighing over 1 oz. costs the same as a mail piece in a 9 x 12 envelope weighing over 1 oz.

Priority Mail

Weighing more than 13 ozs. but less than 70 lbs. not to exceed 108 inches in combined measurements of length and girth. Must be marked as such. The United States Postal System posts a two to three day delivery.

Express Mail

Overnight delivery offered by the USPS. Mail MUST be in the required overnight express packaging and correct mailing label affixed to envelope.

Permit 303 (permit imprint) indicia

First class must be at least 200 pieces identical contents and weight. Mail carrying this indicia will be charged full 1st class rate. Presorted first class indicia must be at least 500 pieces, identical pieces and weight, and in zip code order. Mail carrying this indicia will receive a discounted postage per piece and an additional discount if the mailing is Automation compatible.