Many terms are used when referring to either the amount of a particular nutrient (such as calcium or vitamin D) you should get or the amount in a food or dietary supplement. The two most common are the Recommended Dietary Allowance (RDA) and the Daily Value (DV). These terms can be confusing.
RDAs are recommended daily intakes of a nutrient for healthy people. They tell you how much of that nutrient you should get on average each day. RDAs are developed by the Food and Nutrition Board at the Institute of Medicine of the National Academies. They vary by age, gender and whether a woman is pregnant or breastfeeding; so there are many different RDAs for each nutrient.
DVs, established by the U.S. Food and Drug Administration (FDA), are used on food and dietary supplement labels. For each nutrient, there is one DV for all people ages 4 years and older. Therefore, DVs aren't recommended intakes, but suggest how much of a nutrient a serving of the food or supplement provides in the context of a total daily diet. DVs often match or exceed the RDAs for most people, but not in all cases.
DVs are presented on food and supplement labels as a percentage. They help you compare one product with another. As an example, the %DV for calcium on a food label might say 20%. This means it has 200 mg (milligrams) of calcium in one serving because the DV for calcium is 1,000 mg/day. If another food has 40% of the DV for calcium, it's easy to see that it provides much more calcium than the first food.
The FDA has a Web page that lists the DVs for all nutrients and provides additional details.