Categorize your vitamin D blood level per Endocrine Society guidelines. Understand deficiency, insufficiency, and optimal ranges.
This calculator categorizes your 25-hydroxyvitamin D level per Endocrine Society guidelines. Below 20 ng/mL is generally classified as deficient, 21-29 as insufficient, 30+ as sufficient. The IOM uses 20 ng/mL as sufficient — there is scientific debate. Discuss your optimal target with your healthcare provider.
Written by Ash K · Last updated: June 2026 · Sources cited below
Vitamin D deficiency affects an estimated 42% of US adults, according to research published in Nutrition Research (2011). This calculator estimates whether your current intake from diet, supplements, and sun exposure meets the NIH-recommended daily amount for your age group.
Enter your supplement dose, dietary sources, and estimated sun exposure. The calculator compares your total against the recommended 600–800 IU daily target.
Key Takeaway: NIH recommends 600 IU (15mcg) daily for adults 19–70 and 800 IU (20mcg) for adults 71+. The Endocrine Society suggests higher intakes (1,500–2,000 IU) for adults at risk of deficiency. Most people don't get enough from diet alone — supplementation is often necessary.
| Age Group | NIH RDA | Endocrine Society (at-risk) | Tolerable Upper Limit |
|---|---|---|---|
| Infants (0–12 months) | 400 IU | 400–1,000 IU | 1,000–1,500 IU |
| Children (1–18 years) | 600 IU | 600–1,000 IU | 2,500–4,000 IU |
| Adults (19–70 years) | 600 IU | 1,500–2,000 IU | 4,000 IU |
| Adults (71+ years) | 800 IU | 1,500–2,000 IU | 4,000 IU |
| Pregnant/lactating | 600 IU | 1,500–2,000 IU | 4,000 IU |
Sun exposure is the most efficient source — 10–30 minutes of midday sun on arms and legs produces approximately 10,000–20,000 IU. However, this varies dramatically by latitude, season, skin tone, sunscreen use, and age.
Food sources provide modest amounts:
| Food | Vitamin D per serving |
|---|---|
| Salmon (3 oz cooked) | 450–570 IU |
| Sardines (3 oz canned) | 165 IU |
| Fortified milk (1 cup) | 120 IU |
| Fortified orange juice (1 cup) | 100 IU |
| Egg yolk (1 large) | 40 IU |
| Fortified cereal (1 serving) | 40–80 IU |
| Mushrooms (UV-exposed, 1 cup) | 400 IU |
Note: Without supplementation, most people in northern latitudes (above 37°N — roughly north of San Francisco, Denver, or Richmond, VA) cannot produce adequate vitamin D from sun exposure during winter months (November–March). Blood testing (25-hydroxyvitamin D) is the only way to know your actual level. Optimal is 30–50 ng/mL per the Endocrine Society.
Warning: Vitamin D is fat-soluble — unlike water-soluble vitamins, excess is stored in body fat and can accumulate to toxic levels. The NIH upper limit is 4,000 IU daily for adults. Toxicity (typically from supplementing 10,000+ IU daily for months) causes hypercalcemia — elevated blood calcium with symptoms including nausea, kidney stones, and cardiac arrhythmias. Do not megadose without blood level monitoring.
Bottom Line: Most adults need 600–800 IU vitamin D daily (NIH), with higher doses (1,500–2,000 IU) potentially appropriate for those at deficiency risk. Diet alone rarely provides enough. A vitamin D3 supplement of 1,000–2,000 IU daily is reasonable for most adults — confirm with blood testing if uncertain.
Vitamin D Levels — Endocrine Society Classification
How do I know if I'm vitamin D deficient?
A blood test measuring 25-hydroxyvitamin D is the only definitive method. Levels below 20 ng/mL = deficiency, 20–29 ng/mL = insufficiency, 30–50 ng/mL = optimal per the Endocrine Society.
How much vitamin D should I take daily?
NIH recommends 600 IU (ages 19–70) or 800 IU (71+). The Endocrine Society suggests 1,500–2,000 IU for adults at risk of deficiency. Stay below 4,000 IU unless monitored by your provider.
Can I get enough vitamin D from food?
Difficult without fatty fish or fortified foods. Salmon is the best food source (450–570 IU per serving), but most people would need to eat it daily to meet requirements from food alone.
This tool is for informational and educational purposes only. It is not a substitute for professional medical advice, diagnosis, or treatment. Always consult your healthcare provider with questions about your health.