To convert serving sizes, we incrementally adjust the individual serving size of each ingredient up or down. For example, if you adjust a recipe with 2 servings that needs 1 onion up to 4 servings, we’ll divide the ingredient amount by 2 (1 onion / 2 servings = 0.5 onions) and then multiply that by 4. The end result is 2 onions (0.5 onions x 4 servings).