In any of the following scenarios, a ‘normal’ envelope becomes a package and are subject to non-machinable surcharges:

• Letter-Sized piece with weight over 3.5 ounces
• Letter-sized envelope exceeds any one of the maximum measurements:
  • 11 1/2 inches long x 6 1/8 inches high x 1/4 inches thick
  • If unsure, compare thickness to a postcard or index card

• Any part of the letter-sized envelope is over a 1/4 inch thick.
  • Due to amount of paper
  • Due to paperclips or binder clip
  • Due to strings, buttons, or clasps
  • Due to loose items within envelope
  • If the contents of the envelope (letter-sized or large) is too rigid / not flexible enough to go through the machine, ​​due to pens, keys, or coins that are included inside the envelope.
     
• Large Envelopes (Flats) with weight over 13 ounces
• Large envelope exceeds any one of the maximum measurements: 15 inches long x 12 inches high x 3/4 inches thick