Vitamin D Deficiency Dosage Calculator
Enter your current Vitamin D blood level, target level, weight, and sun exposure to get personalized correction and maintenance doses.
From blood test (4-100 ng/mL). Deficient: <20, Insufficient: 20-30, Optimal: 30-50
Target level (30-50 optimal, 40-60 for athletes/immune health)
Higher body weight requires higher doses (Vitamin D is fat-soluble)
Affects how much Vitamin D your body produces naturally
How much Vitamin D do I need if I'm deficient?
For deficient levels (under 20 ng/mL or 50 nmol/L), typical treatment is 50,000 IU weekly for 8 weeks, or 6,000-10,000 IU daily for 2-3 months. For insufficiency (20-30 ng/mL), 2,000-4,000 IU daily is typical. Always test levels after 3 months and adjust. Maintenance dose after correction is usually 1,000-2,000 IU daily, but some need 3,000-5,000 IU long-term based on weight, latitude, and skin tone.
What blood level should I aim for with Vitamin D?
Optimal range is 30-50 ng/mL (75-125 nmol/L) for most health benefits. Some experts recommend 40-60 ng/mL for immune health, cancer prevention, and mood regulation. Levels above 100 ng/mL can be toxic. Athletes may benefit from 40-50 ng/mL for muscle function and injury prevention. Test every 3-6 months when supplementing high doses.
Does body weight affect Vitamin D dosage needs?
Yes, significantly. Vitamin D is fat-soluble and gets sequestered in body fat. People with obesity (BMI 30+) need 2-3x higher doses to achieve the same blood levels. A 200 lb person may need 5,000-7,000 IU daily for correction, while a 150 lb person needs 3,000-5,000 IU. The calculation uses weight-based dosing: ~40-60 IU per pound for maintenance, 100-150 IU per pound for correction.
Should I take Vitamin D2 or D3 supplements?
Always choose D3 (cholecalciferol) over D2 (ergocalciferol). D3 is 2-3x more effective at raising blood levels and is the same form your skin makes from sunlight. D2 is plant-based but has shorter duration and lower potency. Look for D3 with K2 (100-200 mcg) to prevent calcium buildup in arteries. Take with fat-containing meal for 30-50% better absorption.