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Vitamin Calculator

Health

See recommended daily intake for vitamins A, C, D, E, and K based on your age and sex, using official US dietary reference intake guidelines.

Reviewed by the thecalcu.com team · Last updated July 10, 2026

Gender
Age Group

Daily Vitamin RDA

Male, 19-50 years

Vitamin A— mcg RAE/day
Vitamin C— mg/day
Vitamin D— IU/day
Vitamin E— mg/day
Vitamin K— mcg/day

What is a Vitamins?

A Vitamin Calculator shows your recommended daily intake across five key vitamins, A, C, D, E, and K, based on your age and sex, using official NIH Office of Dietary Supplements dietary reference intakes. Rather than looking up each vitamin's RDA separately, this tool gives you a single side-by-side comparison table so you can see all five values at once for your specific demographic group.

These five vitamins span both fat-soluble nutrients (A, D, E, K), which are stored in the body and carry some toxicity risk if oversupplemented, and one key water-soluble vitamin (C), which is generally safer in excess since surplus amounts are excreted rather than stored. For deeper, life-stage-specific detail on individual vitamins, see the dedicated Vitamin A Calculator and Vitamin D Calculator.

Why Use a Vitamin Calculator?

Looking up RDA values for multiple vitamins one at a time is tedious, and nutrition labels and supplement bottles often use inconsistent units that make comparison difficult. This calculator consolidates the most commonly referenced vitamins into one clear table, tailored to your exact age and sex.

It's especially useful when reviewing a multivitamin label and wanting a quick sanity check against official guidelines, or when planning a diet that needs to meet baseline vitamin targets across multiple nutrients at once.

Who Should Use This Calculator?

  • Anyone evaluating a multivitamin supplement who wants to compare its listed amounts against official RDA benchmarks.
  • People building a balanced diet plan who want a quick reference for multiple vitamin targets at once.
  • Nutrition students and educators needing a fast side-by-side RDA comparison across common vitamins.
  • Older adults whose vitamin D and other requirements shift at age 51 and 71, wanting to see the updated values.
  • Anyone curious how their vitamin needs differ from a partner or family member of a different age or sex.

What Insights Does the Vitamin Calculator Give You?

  • Vitamin A (mcg RAE/day), your recommended daily intake for immune function, vision, and cell growth.
  • Vitamin C (mg/day), your recommended daily intake supporting immune function, collagen production, and antioxidant activity.
  • Vitamin D (IU/day), your recommended daily intake supporting calcium absorption and bone health.
  • Vitamin E (mg/day), your recommended daily intake supporting antioxidant protection and immune function.
  • Vitamin K (mcg/day), your recommended daily intake supporting blood clotting and bone metabolism.

How to use this Vitamins calculator

  1. Select your Gender using the toggle.
  2. Select your Age Group from the list of standard NIH age brackets.
  3. Review the results table showing your RDA for all five vitamins at once.
  4. Compare these values against a supplement label or your typical diet to spot potential gaps.
  5. Recalculate if you move into a new age bracket, such as turning 51 or 71.
Show formula & methodology ↓Show less ↑

Formula & Methodology

This calculator performs a direct lookup against the NIH Office of Dietary Supplements Dietary Reference Intake tables, cross-referenced by sex and age group, for each of the five vitamins.

Worked example: A 45-year-old woman (19-50 age group):

| Vitamin | RDA |
|---|---|
| Vitamin A | 700 mcg RAE/day |
| Vitamin C | 75 mg/day |
| Vitamin D | 600 IU/day |
| Vitamin E | 15 mg/day |
| Vitamin K | 90 mcg/day |

These values represent her daily targets across the five vitamins based on official US dietary reference intakes for her age and sex.

Frequently Asked Questions

What vitamins does this calculator cover?
This calculator provides recommended daily intake (RDA) values for vitamins A, C, D, E, and K based on your age and sex, using official NIH Office of Dietary Supplements dietary reference intakes. For a more detailed, life-stage-specific breakdown of vitamin A or D individually, use the [Vitamin A Calculator](/vitamin-a-calculator/) or [Vitamin D Calculator](/vitamin-d-calculator/).
Why do vitamin RDAs differ by age and sex?
Nutrient needs change across the lifespan due to differences in growth, body size, hormonal changes, and metabolic demands, for example, men generally need more vitamin A and K than women due to differences in average body size, while requirements shift again at older ages.
What units are used for each vitamin?
Vitamin A is measured in mcg RAE (Retinol Activity Equivalents), Vitamin C and E in milligrams (mg), Vitamin D in International Units (IU), and Vitamin K in micrograms (mcg), these are the standard units used in US dietary guidelines and most supplement labeling.
Why isn't vitamin B12 or other B vitamins included?
This calculator focuses specifically on vitamins A, C, D, E, and K, which are the primary fat-soluble (A, D, E, K) and a key water-soluble (C) vitamin most commonly referenced together in general nutrition planning. B vitamins have their own distinct set of RDAs and are not included in this particular tool.
What is the difference between fat-soluble and water-soluble vitamins?
Vitamins A, D, E, and K are fat-soluble, meaning they're stored in body fat and the liver and can accumulate to toxic levels if oversupplemented, while Vitamin C is water-soluble, meaning excess amounts are typically excreted in urine rather than stored, making toxicity far less common.
Can I get all these vitamins from food alone?
Yes, a varied diet including fruits, vegetables, whole grains, dairy, and lean proteins can typically meet RDAs for all five vitamins covered here, though certain groups, including older adults, people with limited sun exposure (vitamin D), or those with restrictive diets, may benefit from supplementation under medical guidance.
Why do pregnant or breastfeeding women often need different amounts?
Pregnancy and breastfeeding increase nutrient demands to support fetal growth and milk production, which is why several vitamins, especially A and C, have separate elevated RDAs for these life stages that aren't captured in this general age/sex calculator, check the individual [Vitamin A Calculator](/vitamin-a-calculator/) for pregnancy-specific values.
What happens if I don't get enough of these vitamins?
Deficiencies vary by vitamin, inadequate Vitamin A can affect vision and immunity, Vitamin C deficiency can impair wound healing and cause scurvy in severe cases, Vitamin D deficiency weakens bones, Vitamin E deficiency is rare but can affect nerve function, and Vitamin K deficiency impairs blood clotting.
Is more always better when it comes to these vitamins?
No, fat-soluble vitamins A, D, E, and K can reach toxic levels with excessive supplementation since they're stored in the body, so staying near the RDA rather than significantly exceeding it (without medical guidance) is generally the safer approach.
How often should I recheck my vitamin RDA?
Recheck whenever your age group changes (crossing into a new bracket like 51-70 or 71+) or if your life circumstances change significantly, such as becoming pregnant or breastfeeding, since RDAs shift at these transition points.
Does this calculator account for smoking status?
No, while smokers are sometimes advised to increase Vitamin C intake due to higher oxidative stress, this general calculator uses standard age/sex RDA values and doesn't adjust for smoking status or other individual health conditions.
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