Classes of Mail
The USPS has several classes of mail that mail services uses to process outgoing mail. Below is a list of mail classes with a brief description.
Postcards
Postcards are typically a single piece of card stock with the following characteristics:
- Maximum thickness of 0.016 inches
- Minimum dimensions are 3 ½ inches (height) x 5 inches (length)
- Maximum dimensions are 4 ¼ inches x 6 inches
- If mail piece exceeds the maximum length or height or thickness, it will be charged at the next higher price or mail category
Post cards are delivered within 1-3 business days.
Letters
Letters have the following characteristics:
- Maximum thickness of 1/4 inches
- Minimum dimensions are 3 1/5 inches (height) x 5 inches (length)
- Maximum dimensions are 6 1/8 inches (height) x 11 ½ inches (length)
- If mail piece exceeds the maximum length or height or thickness, it will be charged at the next higher price or mail category
- Unusually shaped mail such as square or vertical envelopes, lumpy or rigid envelopes and mail with clasps, strings, buttons, etc. must be hand cancelled. They are charged with a non-machinable surcharge even if they weigh less than one ounce. The price is set by USPS
Letters are delivered within 1-3 business days.
Large Envelopes
Large envelopes or flats have the following characteristics:
- Maximum thickness of 3/4 inches
- Minimum dimensions are 6 1/8 inches (height) x 11 ½ inches (length)
- Maximum dimensions are 12 inches (height) x 15 inches (length)
- Large envelopes that exceed maximum dimension are rigid, non-rectangular or not uniformly thick are charged at Parcel prices
Large envelopes are delivered within 1-3 business days.
Packages or Parcels
Packages have the following characteristics:
- Minimum dimensions are 12 inches (height) x 15 inches (length)
- Maximum length plus girth of 108 inches (length is the measurements of the longest dimension and girth is the distance around the thickest part of the package, perpendicular to length
- Packages may also be a small box or tube
Media Mail
Media Mail® is a cost-effective way to send media and educational materials. This service has restrictions on the type of media that can be sent. The following may be sent via Media Mail®:
- Books (at least eight pages)
- Printed music and test materials
- Video and sound recordings
- Printed educational charts
- Medical loose-leaf pages and binders
- Computer-readable media
- Note: video games, computer drives and digital drives do not qualify for Media Mail® prices
Maximum weight is 70 pounds. There is no minimum weight restriction, but Parcel rate may be cheaper depending on the weight of the mail piece. Contact mail services for additional information.
USPS Services
The USPS provides a variety of services with delivery of the above classes of mail.
Certified Mail
Use Certified Mail to have access to information on delivery or delivery attempt(s) made. When combined with Return Receipt, you can get the signature of the person who accepts the mailing. Provide the following information to mail services to utilize this service:
- Provide the fund and cost center form (Department Charge for U.S. Postage and Special Services form) and indicate Certified Mail
- Include a completed certified mail form (PS Form 3800)
You may combine certified mail with Restricted Delivery or Return Receipt. Both services are described in more detail below.
Restricted Delivery
This service offers the sender the ability to specify the person allowed to sign for and receive the item. This service must be purchased in combination with one of the other extra services below:
- Certified Mail
- Insured Mail (over $500)
- Registered Mail
- Signature Confirmation
Identification may be requested for the addressee or person authorized to sign for and receive the item.
Return Receipt
Return receipt allows you to receive electronic or hard-copy delivery record showing the recipient's signature.
Registered Mail
Use registered mail when sending valuable items. This allows items to be insured for up to $50,000. You will receive a mailing receipt and upon request, electronic verification of delivery or delivery attempt.
- Purchase at a local Post Office
- Regardless of purchase method, present registered mail items for mailing to a postal employee
Signature Confirmation
Signature confirmation allows you to have information about the date and time an item was delivered or a delivery attempt was made. You may also require a signature. The USPS keeps record of delivery, which is available electronically or by email, upon request. Limited availability to APO/FPO/DPO locations and certain Freely Associated States.
Collect on Delivery (COD)
Use COD if you want the mail piece recipient to pay for merchandise and shipping upon package receipt. Insurance coverage is also provided up to $1,000 based on amount to be collected or amount of insurance coverage desired, whichever is higher.
- Purchase at a local Post Office, depending on the mail class chosen. Present COD for mailing to a Postal Employee
- Mailing receipt is provided
This service is not available for international shipments, APO/FPO/DPO locations and certain Freely Associated States.
Certificate of Mailing
A certificate of mailing provides an official record of the date your mail was presented to USPS for mailing. This services is only available at the post office and at the time of mailing.
Priority Mail
Priority mail is any letter, large envelope, package or parcel.
- Mail piece weights more than 13.1 ounces and up to 70 pounds
- A USPS tracking number is provided
- Delivery in 1-3 business days
- Up to $50 of insurance, no surcharges for fuel or residential, rural and regular Saturday delivery
- Also available are Priority Mail Flat Rate envelopes
- Reference USPS.com for pricing information
Priority Mail Express
Priority mail express provides the sender with proof of delivery signature record, if requested at time of purchase, and tracking information with USPS tracking with quicker delivery.
- Weight maximum of 70 pounds
- Up to $100 of insurance is provided with most shipments
- Overnight scheduled delivery by 10:30 a.m. or on a Sunday or holiday available in many major markets with an additional fee
- Scheduled delivery date depends on origin, destination and drop-off time
- Flat rate pricing is available
- Reference USPS.com for pricing
- Packages shipped to a Military Post Office (APO/FPO/DPO) pay domestic prices, but require a customs form and have specific restrictions, which can be viewed on USPS.com
Exceptions for this service apply. See USPS.com for more detail.