As simple as it is to throw together a salad, there’s often one major challenge: buying the right amount of greens. While recipes usually call for greens by volume in cups, they tend to be sold in other forms: by weight or by the bunch, head, bag or box. Plus, many recipes call for already-prepped greens. Since there’s a drastic difference in volume between whole and prepped greens, it’s especially difficult to gauge the amount you need by sight alone.

To make shopping simpler, we measured 15 varieties of greens—from frisée to collards—first prepping them, if needed, in the way they’re commonly used. We found that with loose greens, 1 ounce of greens is equivalent to roughly 1¼ cups. By comparison, lettuce heads yield approximately ½ cup chopped greens per ounce once prepped. And cabbages and endives produce roughly ⅓ cup per ounce once prepped.