How to Calculate RDA in Nutrition

Written by matthew caines
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How to Calculate RDA in Nutrition
RDAs can help you maintain a healthy and balanced diet. (Comstock/Comstock/Getty Images)

Recommended Daily Allowance, also known as RDA, is the average dietary intake level a person should follow to meet their nutritional requirements. RDAs are printed and distributed by health organisations to ensure people have a general guideline to follow when planning their dietary regimens. RDAs are given for most nutritional items such as macronutrients, calories, vitamins and minerals. You should calculate these figures online because there is no set pattern to working out how much of something you need. Also, the sheer amount of values you would need to calculate, around 50, would require dozens of formulas and could take several hours to work out.

Skill level:

Things you need

  • Computer
  • Internet
  • Printer

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  1. 1

    Launch your Internet browser and navigate to a web site that provides RDA values. Web sites such as the United States Department of Agriculture and Diet & Fitness Today are particularly helpful because they calculate personal RDAs based on information you give about your gender, age, height, weight and exercise activity.

  2. 2

    Type your personal details in the boxes provided. The details you give will determine your personal RDA so make sure the information is accurate and correct. Most RDA calculators will ask for your age, height and weight.

  3. 3

    Insert a value for your physical activity from the drop-down menu. Choose between values such as very active, active and sedentary. Be honest. Your RDA is calculated for your benefit, so even if you exercise less often than you think you should, your RDA will let you know how to keep a balanced diet.

  4. 4

    Check the boxes of the fields you want to calculate an RDA for. Some sites will automatically reveal everything for you but others let you tailor your results just for calories or specific vitamins. Confirm your selection and view your results by clicking the "Calculate" button.

  5. 5

    Look at your personalised results. You can check how many calories you should be consuming per day as well as specific values for vitamins, minerals and macronutrients such as fat, carbohydrates, protein and fibre.

  6. 6

    Print off the page if you would like a copy of your results. Stick the results to the fridge in your kitchen if you need a reminder of your RDA before every meal.

Tips and warnings

  • Sites such as Pure Lifestyle also offer a general values sheet that details approximate values for RDAs based on your age and gender. For example, a 13-year-old boy would have 5 grams for his recommended daily allowance of salt. See the Resources section for a copy of the basic RDA sheet.
  • Some web sites have links next to some of the result values. Click on these links to see extra information about the RDA. This might be a note on accuracy or a sample diet to help you control your diet.

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