How many stamps do you need to mail a letter that weighs 90.7 grams from the US to Australia?

To mail a letter weighing 90.7 grams from the US to Australia, you would typically need to use international postage. As of my last update, a standard international stamp covers a weight limit of up to 20 grams, so you would require multiple stamps or a higher weight postage option. For a letter of that weight, you may need to use a combination of stamps or a specific international mailing service. It's best to check with the USPS for the most accurate and current postage rates.