How many stamps do I use for a letter to Canada?

It takes three regular postage stamps to mail a letter from the U.S. to Canada. It costs $1.15 to mail a letter to Canada from the United States as of 2017.

Each postage stamp is worth 49 cents. Therefore, it takes three of them to cover the cost of $1.15. However, that is more postage than is needed to mail the letter, as the three stamps are equal to $1.47. Stamps in smaller amounts, such as 4-cent stamps or postage stamps can be purchased to help cover the cost of the letter instead of using all regular postage stamps. Also, the letter can be mailed from a post office for the exact amount.