First Class Mail Shape Based Classification Tool

Determine if your mail piece is a Postcard, Letter, Large Envelope, or Package

For First-Class Mail®, USPS rates are based on the size and thickness of your mail piece. Follow the instructions below to determine the type of First-Class Mail® you are trying to send.

Step 1: Measure your mail piece

Letter-sized pieces

Length is the dimension that is parallel to the address.

mail_envelope mail_envelope-short

Large envelopes and packages

Length is the longest dimension.

mail_package

Step 2: Find the aspect ratio

icon_postcard
icon_letter
icon_envelope

Step 3: Determine your mail piece shape

mail_letter

Step 4: Print postage and send your mail piece

Perks of your risk-free trial

  • Free mailing supplies
  • Free 5 lb digital scale
  • Free scheduled pickups
  • No contract, cancel any time
Get Started