Vitamin D Dosing Calculator

Calculate daily vitamin D (IU) needed to reach your target serum level based on current level, weight, and sun exposure.

Current Level (ng/mL)

Target Level (ng/mL)

Body Weight (lbs)

Sun Exposure

Tab to move between fields

Daily Dose

3,100 IU

Maintenance Dose

1,200 IU

Weekly Dose21,700 IU

Months to Target1 months

How to Use This Calculator

Enter your most recent serum 25(OH)D level in ng/mL from a blood test.
Set your target vitamin D level (30-50 ng/mL is generally considered optimal).
Input your body weight in pounds and your sun exposure level (Low, Moderate, or High) - both affect the recommended dose.
Review the Daily Dose and Weekly Dose in IU needed to reach your target, along with the estimated Months to Target.
Once you reach your target level, use the calculated Maintenance Dose to sustain it going forward.

How the result changes with Target Level (ng/mL)

Current Level (ng/mL): Your current serum 25(OH)D level from a blood test (deficient <20, insufficient 20-29)
Target Level (ng/mL): Desired serum level (30-50 ng/mL is generally considered optimal)
Body Weight (lbs): Your body weight — heavier individuals typically need higher doses
Sun Exposure: 1 = Low (indoor/winter), 2 = Moderate (some outdoor time), 3 = High (regular outdoor sun)

Identify Input Parameters
4 parameters
Current Level (ng/mL) = 20, Target Level (ng/mL) = 50, Body Weight (lbs) = 160, Sun Exposure = 1 = 4 input(s) provided
Calculate Daily Dose
Daily Dose
3100 = 3100
Calculate Weekly Dose
Weekly Dose
21700 = 21700
Calculate Months to Target
Months to Target
1 = 1

Engine last updated August 6, 2026. Checked against 3 independently-derived tests — how we verify calculators.

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