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

$60 in free postage and supplies when you sign up!

  • $5 in free postage added to your account
  • 5 lb digital scale (only pay for S&H)
  • Free mailing and shipping supplies kit
  • Risk-free 30-day trial
  • No long-term contracts. Cancel anytime.
Get Started