How many carbohydrates Merlot has depends on the brand. For example, a glass of Sutter Home Merlot has 4.1 grams of carbohydrates in a 5-ounce serving. That same amount has 119 calories, and it has less than a gram of protein.
Yellow Tail's Merlot has slightly less carbohydrates, since it has 4 grams of carbohydrates in 6 ounces rather than 5; the 6-ounce glass has 120 calories. Only half of those carbohydrates come from sugars. The website nutrition data gives the average for a Merlot as 4 grams of carbohydrates for 5 ounces. That serving is 122 calories.