Vitamin D Calculator
Your recommended daily vitamin D by age
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Vitamin D supports bone health and immunity. General guidance is 400 IU/day for infants, 600 IU/day for children and adults, and 800 IU/day for those over 70. Sunlight, oily fish and fortified foods are the main sources; supplements help when sun exposure is low.
Frequently Asked Questions
- How much vitamin D do I need per day?
- Most adults need about 600 IU (15 mcg) of vitamin D daily, rising to 800 IU (20 mcg) after age 70. This calculator tailors the recommendation to your age and status and reports it in both international units and micrograms.
- What is the safe upper limit for vitamin D?
- For adults, the usual upper intake level is 4,000 IU (100 mcg) per day from food, drinks and supplements combined. It is an upper limit, not a recommended supplement dose. Age-specific limits are lower for children. A clinician may prescribe a different amount for a diagnosed condition.
- How can I get more vitamin D naturally?
- Sunlight on bare skin is the main source, supported by foods like oily fish, egg yolks and fortified milk or cereal. Because sun exposure varies with season, latitude and skin tone, many people in winter rely on diet or a supplement to meet their needs.