Vitamin D Calculator
Vitamin D doses come in IU or micrograms, and often as a weekly or monthly sachet. Enter yours to see it in both units, as an average per day, and against the recommended intake and the safe upper limit.
Your dose
IU
Enter a dose
= µg
1 µg = 40 IU (US National Academies)
Average per day
IU
= µg a day
Daily need
IU
US RDA µg · India (ICMR-NIN 2020) IU
Upper limit 100 µg (4,000 IU) a day
The US daily figures assume minimal sun exposure. This calculator doesn't work out a treatment dose from a blood test — that's for your doctor.
Your results are attached to the form below
These figures are estimates for general awareness only and are not medical advice or a diagnosis. Read our Medical Disclaimer.
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How this is calculated
1 µg of vitamin D (cholecalciferol) = 40 IU, per the US National Academies' DRI tables. Average per day = dose ÷ 7 for weekly, ÷ 30 for monthly. US/Canadian RDA: 15 µg (600 IU) a day for adults up to 70 and 20 µg (800 IU) over 70, assuming minimal sunlight; upper limit 100 µg (4,000 IU). ICMR-NIN 2020: adult RDA 600 IU, EAR 400 IU.
Sunlight and vitamin D
ICMR-NIN's 2024 Dietary Guidelines for Indians recommend sunlight exposure for vitamin D, and advise pregnant women to get at least 15 minutes of direct sunlight. The US daily figures assume very little sun, which is why they're set relatively high.
About the upper limit
The US upper limit is 4,000 IU (100 µg) a day from all sources. It is not meant to apply to people being treated under medical supervision — so a high-dose course your doctor has prescribed for a deficiency is a different matter. Taking high doses on your own for long periods is not.
What this calculator doesn't do
It doesn't work out a treatment dose from a blood test result. That depends on your level, your health and the medicine used, and is for your doctor to decide.
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