As of March 2014, the postage for a letter sent via First Class International Mail from the United States to Alberta, Canada is $3.33. This postage covers one envelope that is no more than 15 inches long, 12 inches high and 0.75 inch thick with contents that are not worth more than $400.
The postage for sending a postcard from the United States to Alberta is $1.15 as of March 2014, assuming that the postcard is no more than 6 inches long and 4.25 inches high.
The U.S. Postal Service offers many other international mailing services. Global Express Guaranteed delivers a letter to Alberta in as little as one to three days, and the postage costs $51.50. A letter sent from the United States to Alberta via Priority Mail International takes six to 10 days to arrive, and postage costs $20.55.