ConverterHub

Daily Vitamin D Requirement Calculator

Enter age and pregnancy status to find the daily vitamin D target.

Result

800 IU
20.0 µg
5,600 IU

How it is calculated

The tool looks up a fixed daily target from your age in years, using three bands: under 1 year: 400 IU, 1 to 70 years: 600 IU and over 70 years: 800 IU. An age of exactly 70 is still in the 600 IU band, and 71 moves to 800 IU. It then converts with mcg = IU ÷ 40 (1 µg = 40 IU) and multiplies by 7 for a weekly total. If you select pregnancy at ages 14 to 50, the tool sets the target to 600 IU, which is already the figure for that age band, so the answer does not change. Breastfeeding is not a separate option. The result is a general intake figure from one set of guidelines, not a dose for someone with a deficiency or a medical condition, and it does not account for sun exposure or what your diet already supplies.

Worked example

A 72-year-old, not pregnant. The age is over 70, so the target is 800 IU a day. In micrograms: 800 ÷ 40 = 20.0 µg. Over a week: 800 × 7 = 5,600 IU. If your supplement label says 25 µg, that equals 25 × 40 = 1,000 IU, which is above this daily figure; label amounts need converting the same way before you compare them.

Try this example →

Common mistakes

  • Comparing micrograms with IU directly. 20 µg is 800 IU, not 20 IU, so convert with the factor of 40 first.
  • Entering age in months for an infant. The field is years, so 6 months is 0.5.
  • Expecting pregnancy to raise the number. In this tool it stays at 600 IU for ages 14 to 50, the same as for a non-pregnant adult.
  • Treating the figure as the right dose for someone with a diagnosed deficiency. Treatment doses are set by a clinician, usually after a blood test.
  • Counting only the supplement. Food, fortified products and sunlight also contribute, which the tool does not estimate.

Sources

About this calculator

Dietary guidelines set a Recommended Dietary Allowance (RDA) for vitamin D that varies by age — typically around 600 IU/day for most children and adults, rising to about 800 IU/day for adults over 70 (for infants under 1 year the guideline is an Adequate Intake of 400 IU/day rather than an RDA). Pregnancy does not raise the 600 IU/day target, and the calculator's pregnant/breastfeeding setting leaves it unchanged. Vitamin D is measured in both International Units (IU) and micrograms (mcg), related by 1 mcg = 40 IU.

Dietitians and healthcare providers use these figures when advising on supplementation, especially for people with limited sun exposure, darker skin, or conditions that reduce absorption, and individuals use the calculator to check how a supplement's IU or mcg dose stacks up against their age-based target.

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