The exact number of stamps needed on a Christmas card will depend on various factors such as the country or region where you're sending the card, the weight and size of the card, and the type of postage you're using (such as regular mail, first-class mail, or international mail). In the United States, for example, a standard Christmas card weighing less than an ounce would require a single first-class stamp. However, if the card weighs more than an ounce, additional postage will be required. It's always best to check with your local post office for specific postage rates and requirements.