Vitamin D Requirement Calculator

Calculate the recommended daily dosage of vitamin D based on age, weight, current level, and sun exposure. Based on EFSA and Endocrine Society guidelines.

How Much Vitamin D Do You Need Daily

Vitamin D is essential for bone health, the immune system, and muscle function. Vitamin D deficiency is a widespread problem: approximately 40% of the global population has insufficient levels, especially during winter months.

How the Calculation Works

The calculator estimates daily vitamin D requirements considering:

Age: infants need 400 IU, adults 600 IU, those over 75 need 800 IU
Current level: in cases of documented deficiency, doses increase significantly
Sun exposure: those who stay indoors or use sunscreen produce less vitamin D
Special conditions: pregnancy, osteoporosis, and malabsorption require higher doses

Units of Measurement

Vitamin D is measured in IU (International Units) or mcg (micrograms). The conversion is simple: 1 mcg = 40 IU. On supplements you will often find both units.

Recommended Levels

Age	Daily dose	Dose in mcg
0-12 months	400 IU	10 mcg
1-17 years	600 IU	15 mcg
18-74 years	600 IU	15 mcg
75+ years	800 IU	20 mcg
Pregnancy/breastfeeding	600 IU	15 mcg

When to Supplement

Supplementation is recommended for all those over 65, pregnant and breastfeeding women, people with limited sun exposure, those with osteoporosis, celiac disease or malabsorption, and those taking corticosteroids long-term.

Frequently Asked Questions

How much vitamin D do you need per day?▼

According to EFSA, the daily requirement is: 400 IU (10 mcg) for infants (0-12 months), 600 IU (15 mcg) for children, adolescents, and adults up to 74, 800 IU (20 mcg) for those over 75. In cases of documented deficiency, a doctor may prescribe higher doses (up to 4000 IU/day for adults) for limited periods.

Can you take too much vitamin D?▼

Yes, excess vitamin D (hypervitaminosis D) is possible with prolonged high-dose supplementation. The upper tolerable limit is 4,000 IU/day for adults according to EFSA. Intoxication (very rare) causes hypercalcemia with symptoms like nausea, vomiting, and muscle weakness. You cannot get intoxicated from sun exposure, as the skin self-regulates production.

Is sunlight enough to produce vitamin D?▼

Sun exposure is the primary source of vitamin D: the skin produces about 10,000-20,000 IU with 15-30 minutes of direct sun on face and arms. However, at higher latitudes, UVB rays are too weak in winter to activate production. Sunscreens with SPF >30 block 95% of synthesis.