What are the most common envelope sizes?

Envelopes are available in many different sizes. Each size is referred to by a number. The most common ones are listed below.

  • #6 1/4 – 3 1/2″ x 6″
  • #6 3/4 – 3 5/8 x 6 1/2″
  • #7 – 3 3/4″ x 6 3/4″
  • #7 3/4 – 3 7/8″ x 7 1/2″
  • #8 5/8 – 3 5/8″ x 8 5/8″
  • #9 – 3 7/8″ x 8 7/8″
  • #10 – 4 1/8″ x 9 1/2″
  • #11 – 4 1/2″ x 10 3/8″
  • #12 – 4 3/4″ x 11″
  • #14 – 5″ x 11 1/2″