Can I make USPS First Class International postage online?
I am not sure why this is but you cannot purchase online postage for First-Class Mail International, only for Priority or Express. If you want to use one of those rates, go to www.usps.com, select “Calculate Postage” at the top of the screen. Click on “Calculate International Postage” in the middle of the screen. Select the country of destination from the drop down menu. Select the shape of what you are mailing. Enter the weight of your piece. That will take you to a page where you select the class that you want and you can print the postage. Be sure to fill out the proper custom forms.
