How To Calculate Rda For Calcium


Have you ever wondered how to calculate RDA for Calcium? RDA stands for Recommended Daily Allowance. It’s an easy way to ensure that you get the required daily amount of a specific nutrient your body needs.  Who isn’t talking nowadays about the importance of calcium among kids? Is it really that important? That is exactly what we’re going to discover in this post. Let’s start right away!

How To Calculate Rda For Calcium

Over 40% of the U.S population does not get a sufficient daily amount of calcium.1 Calcium is essential for maintaining normal bone health and structure, and it also has other vital functions such as assisting with muscle function and nerve transmission.2

Milk outside in a bottle and a glass

Benefits of Calcium

Getting enough calcium can help your body in different ways, most notably by keeping your bones healthy and strong. In fact, 99% of the calcium in the body is stored in bones and teeth.3

Your body is constantly breaking down and remodeling bone, and you need calcium to help rebuild your bone. Calcium also helps your body maximize the size and strength of your bone, also known as peak bone mass.

Although your genes primarily determine your peak bone mass, calcium can be an influencing factor. Most people don’t reach peak bone mass until the ages of 25 to 30.4 From age 25 to 50, bone density tends to stay stable, and it usually begins to break down after age 50.5

A diet that includes adequate calcium consumption from childhood to adulthood can help the peak bone mass reach its greatest potential, which can delay bone loss when the bone starts to break down with age.

Calcium also plays an important role in other bodily functions. It’s needed for the chemical processes that cells use to carry out a variety of actions in the body, such as releasing essential enzymes for digestion6 and enabling muscles to contract, including the heart muscle.7

What Happens If You Don’t Get Enough

Not getting enough calcium can be harmful to your health. Since calcium is required for so many vital functions, your body will take it from your bones if you don’t get enough in your diet.8 This can weaken your bones and make them more susceptible to fractures.

A severe calcium deficiency can lead to a condition known as hypocalcemia, which is when there is deficient calcium in the blood.

Hypocalcemia may lead to symptoms such as:

  • Muscle cramps
  • Convulsions
  • Tingling in the fingers
  • Poor appetite
  • Abnormal heart rhythms
  • Seizures

The Role of Vitamin D

Vitamin D is important for calcium absorption. However, according to the Dietary Guidelines for Americans, up to 90% of adults are not receiving an adequate amount of vitamin D from their diet.1 Vitamin D and calcium supplementation may help you get enough of these nutrients if you’re deficient in them.

How Much Calcium You Need Per Day

The Recommended Dietary Allowance (RDA) is the national system of nutrition recommendations. In 2020, The U.S. Department of Agriculture (USDA) and the U.S. Department of Health and Human Services (HHS) jointly released updated Dietary Guidelines for Americans, which set the following RDAs for calcium:1


  • Age 2 to 3 years: 700 milligrams (mg)
  • Age 4 to 8 years: 1,000 mg


  • Age 9 to 18 years: 1,300 mg
  • Age 19 to 50 years: 1,000 mg
  • Over Age 51 years: 1,200 mg

Pregnant Women

  • Under Age 19: 1,300 mg
  • Age 19 and Over: 1,000 mg

Lactating Women

  • Under Age 19: 1,300 mg
  • Age 19 and Over: 1,000 mg


  • Age 9 to 18 years: 1,300 mg
  • Age 19 to 70 years: 1,000 mg
  • Over Age 71 years: 1,200 mg

The Best Way to Get Calcium

The best way to get calcium is from natural sources in your diet. Dietary sources are absorbed into the body more efficiently than calcium supplements9 and different types of calcium-rich foods also contain other important nutrients that your body needs, like protein, iron, vitamin A, vitamin D, and vitamin C.

Dietary Sources

A variety of foods contain ample amounts of calcium. Below is a table of some of the best dietary sources.3

 Food Serving size Milligrams (mg) of calcium per serving
Spinach, boiled and drained 1/2 cup 123
Yogurt, plain, low fat 8 ounces 415
Orange juice, calcium-fortified 1 cup 349
Cheddar cheese 1.5 ounces 307
Milk, nonfat 1 cup 299
Tofu, processed with calcium 1/2 cup 200
Salmon, pink, canned, solids with bone 3 ounces 181
Hot cereal, calcium-fortified 1 cup 150
Almonds, whole  1/4 cup 100
Kale, chopped/cooked 1 cup 95
Sardines, canned with, bones 2 fish 92
Chia seeds 1 tablespoon 76
Pinto beans 1 /2 cup 54
Apple, with skin Medium 10
Raw broccoli 1 cup 21


If you aren’t getting an adequate amount of calcium from natural sources, calcium supplementation may be an option to try.

There are four main types of calcium supplements:

  • Calcium carbonate
  • Calcium citrate
  • Calcium lactate
  • Calcium gluconate

Each type has varying amounts of elemental calcium, which is the actual amount of calcium that the body can absorb.

Supplement Amount of Elemental Calcium
Calcium carbonate 40%
Calcium citrate 21%
Calcium lactate 13%
Calcium gluconate 9%

Calcium carbonate is absorbed with the aid of stomach acid, so it’s important to take it with food.3

Calcium citrate is easier for the body to absorb and does not need to be taken with food.3 Because of this, calcium citrate can be a good option for people who have an absorption disorder or inflammatory bowel disease (IBD).3

Calcium lactate and calcium gluconate may be found in over-the-counter supplements. And calcium gluconate is used in IV therapy to treat hyperkalemia, which is an excess amount of potassium in the blood

How to Estimate Your Daily Calcium Intake

Step 1: Estimate the number of servings you have on a typical day for each type of food. One serving is equal to approximately:

  • 8 oz. or one cup of milk
  • 6 oz. of yogurt
  • 1 oz. or 1 cubic inch of cheese

The amount of calcium in fortified foods and juices ranges from 80 – 1,000 mg. Some examples are juices, soymilk and cereals.

Step 2: List the estimated number of servings of each food item under “Servings Per Day.”

Step 3: Multiply the number of “Servings Per Day” by the number of milligrams (mg) under “Calcium.” For example: if you have about two servings of milk per day, multiply 2 x 300 to get a total of 600 mg of calcium from milk.

Step 4: After you have calculated the total amount of calcium for each product, add these totals in the right hand column to get your Total Daily Calcium Intake. Note: 250 mg of calcium is automatically added under “Estimated total from other foods.” Most of us get about this amount of calcium each day from other foods like broccoli.

Step 5: Subtract your final total daily calcium intake from the recommended amount of calcium you need each day. This number is the additional calcium you need each day. You can get this additional calcium by adding calcium-rich foods to your diet and/or by taking a calcium supplement.

How Much Calcium per Day | Daily Calcium Intake

Adequate calcium intake is necessary for good health, and not just because of its importance to our bones. Calcium plays a principal role in keeping our skeletal muscles working properly as well as our vital organs. Since our bodies don’t produce calcium naturally, it is up to us to find the right calcium supplements to ensure we receive the recommended daily calcium intake.

Recommended Calcium Intake

Intake recommendations are provided in the Dietary Reference Intakes by the Food and Nutrition Board at the Institute of Medicine. These values look at age, gender, and specific situations. Recommended calcium intake is often broken down by:

Recommended Dietary Allowance (RDA): Refers to the average daily calcium intake sufficient enough to meet the nutrient requirements of healthy individuals.

Adequate Intake (AI): Refers to the levels needed to ensure nutritional adequacy.

Estimated Average Requirement (EAR): Refers to the average daily intake needed to meet the requirements of 50% of healthy individuals.

Tolerable Upper Intake Level (UL): Refers to the maximum daily intake unlikely to cause any adverse health effects.

According to the FNB, these are the recommended dietary allowances (RDA) for calcium.

0-6 months: 200mg

7-12 months: 260mg

1-3 years: 700mg

4-8 years: 1,000mg

9-13 years: 1,300mg

14-18 years: 1,300mg

19-50 years: 1,000mg

51-70 years: 1,000mg for men and 1,200mg for women

71+ years: 1,200 mg

The FNB also sets the standards for tolerable upper intake (UL) levels to make sure people don’t take more calcium than they need.

0-6 months: 1,000mg

7-12 months: 1,500 mg

1-8 years: 2,500mg

9-18 years: 3,000mg

19-50 years: 2,500mg

51+: 2,000mg

How to Estimate Your Daily Calcium Consumption?

Even though our bodies don’t produce calcium, we often get a large part of our recommended calcium intake through our diet. Calcium-rich foods such as produce, seafood, and dairy are great sources of calcium. But, in most cases, calcium intake through our diets alone is not enough.

To determine the estimated amount of calcium you get from food on a typical day, you can use a calcium calculator. Here’s how to calculate your daily calcium intake.

Step 1: Write down the number of servings you have on a typical day for each food type.

Step 2: Multiply your number of servings per day by the number of milligrams under calcium.

Step 3: Add these totals to get the total amount of calcium intake per day.

For example, let’s say on a typical day you get one serving of milk, one serving of yogurt, and one serving of broccoli. This is what your calcium calculator would look like:

Milk (8 oz): 1 Serving per Day x 300mg of Calcium = 300

Yogurt (6 oz.): 1 Serving per Day x 300mg of Calcium = 300

Broccoli (1/2 cup): 1 Serving per Day x 20mg of Calcium = 20

Total calcium intake: 620mg per day.

If you’re between 19-50 years old, that means you have a calcium deficiency of roughly 520mg of calcium. That means you should consider increasing your calcium intake through your diet or consider a calcium supplement.

How to Increase Your Calcium Intake

The fastest way to increase your calcium intake is by including a calcium supplement into your diet that meets your daily needs. Calcium supplements are often combined with other minerals and nutrients to provide you additional health value.

Another way to increase your calcium intake is by incorporating calcium-rich food into your diet. Some foods high in calcium include collard greens, soybeans, sardines, milk, cheese, fortified foods such as almond milk or fortified juices with calcium.

Most people are shocked to find out their calcium intake is well below the average recommended amount. Consider taking a step back and looking at your calcium sources to make sure your body is receiving the minerals it needs to maintain healthy bones healthy muscles, and healthy nerve functions.

Do you need a calcium supplement?

We recommend you always aim to get all the calcium you need as part of a healthy, balanced diet. To see whether you’re getting enough calcium from what you eat and drink, you can use this online calculator, from the University of Edinburgh.

Don’t worry if you don’t get enough calcium everyday. As long as you generally reach the recommended amount, not getting enough on the odd day shouldn’t impact your overall bone health.

If you find you continually don’t get enough calcium in your diet, a calcium supplement can then be considered.

Too much calcium may increase your risk of other health problems. You can find out more about this on the calcium supplements and blood tests factsheet.

Importance Of Calcium

Calcium is an important nutrient that your body needs for many basic functions. Read on to learn more about this mineral and how much you should be getting.

1. Calcium plays a role in your body’s functions

Calcium plays a role in many of your body’s basic functions. Your body needs calcium in order to circulate blood, move muscles, and release hormones. Calcium also helps carry messages from your brain to other parts of your body.

Calcium is a major part of tooth and bone health as well. It makes your bones strong and dense. You can think of your bones as your body’s calcium reservoir. If you don’t get enough calcium in your diet, your body will take it from your bones.

2. Your body doesn’t produce calcium

Your body doesn’t produce calcium, so you have to rely on your diet to get the calcium you need. Foods that are high in calcium include:

  • dairy products such as milk, cheese, and yogurt
  • dark green vegetables such as a kale, spinach, and broccoli
  • white beans
  • sardines
  • calcium-fortified breads, cereals, soy products, and orange juices

3. You need vitamin D to absorb calcium

Your body needs vitamin D in order to absorb calcium. That means you won’t fully benefit from a calcium-rich diet if you’re low on vitamin D.

You can get vitamin D from certain foods, such as salmon, eggs yolks, and some mushrooms. Like calcium, some food products have vitamin D added to them. For example, milk often has added vitamin D.

Sunshine is your best source of vitamin D. Your skin naturally produces vitamin D when exposed to the sun. Those with darker skin don’t produce vitamin D as well, so supplements may be necessary to avoid deficiency.

4. Calcium is even more important for women

Several studies show that calcium may ease symptoms of premenstrual syndrome (PMS). This studyTrusted Source concluded that women with PMS have lower intakes of calcium and magnesium, and lower serum levels.

5. The recommended amount depends on your age

How do you know if you’re getting enough calcium? The National Institutes of Health (NIH)Trusted Source say that adults should get 1,000 mg every day. For women over 50 and during pregnancy and breast-feeding, NIH recommends 1,200 mg daily.

One cup of skim, low-fat, or whole milk contains about 300 mg of calcium. Check the UCSF’s helpful guide to see how much calcium is in many common foods.

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