Try this link, it will give yu all you need to know about stamps and international mailing
http://www.springglobalmail.fr/en/Fact_Files/
You can use forever stamps on an international letter. It is worth 44 cents toward the cost. You must put additional postage on the envelope.
The entire purpose of the Forever Stamps was that you can use them for one ounce of First Class Postage forever. No additional postage is necessary.
You can use forever stamps for an ounce of postage forever. They never lose their value for one ounce of postage.
No you cannot use them. Forever stamps can only be used for domestic (inside the US) mail. They must have a value on them for international mail.
You cannot use Forever stamps on postage outside the US. The rate of one ounce of international First Class Mail is 98 cents.
You cannot use the Forever Stamps on foreign postage. The international agreement indicates that value must be shown on stamps used for international mail. The current cost for up to one ounce is 98 cents.
Q. Can Forever stamps be used for international mail? A. Customers can use Forever stamps for international mail, but since all international prices are higher than domestic prices, customers will need to attach addi­tional postage. The value of the Forever stamp is the domestic First-Class Mail 1-ounce letter price in ef­fect on the day of use. Source: http://about.usps.com/postal-bulletin/2011/pb22306/html/cover.html
You can use forever stamps on the letter. It is worth 44 cents toward the cost. You must put additional postage on the envelope.
You can use forever stamps on a letter to Canada. It is worth only 44 cents toward the cost. You must put additional postage on the envelope.
You can use forever stamps on a letter to Australia. It is worth 44 cents toward the cost. You must put additional postage on the envelope.
No, Forever stamps cannot be used for Media Mail. Media Mail rates are specific and must be paid with the appropriate postage for that service.
In the US postage stamps are always valid. You do still have to have enough to cover the current postage cost. And Forever stamps are always valid for one ounce of first class mail, regardless of the actual cost.