Vitamin D Calculator – Check Levels & Daily Supplement Dose
Assess vitamin D levels, calculate recommended daily intake & supplement dose based on age, sun exposure & risk factors. Free, no sign‑up, educational tool only.
Updated for 2026
Personal Details
✓ Last updated: March 2026 | Built with CRA-official rates, Bank of Canada data, and OSFI guidelines
How to Use This Calculator
Provide your age, gender, and vitamin D level from a blood test.
Select sun exposure level, skin tone, dietary intake, and season.
See your vitamin D status, supplement dose, and recommendations.
Understanding Your Results
- Vitamin D StatusDeficient: <20 ng/mL (50 nmol/L). Insufficient: 20-29 ng/mL (50-75 nmol/L). Normal: 30-100 ng/mL (75-250 nmol/L).
- Supplement DoseMaintenance: 600-1000 IU/day. Loading: 50,000 IU/week for 8 weeks (if deficient).
- Risk FactorsDark skin, low sun exposure, winter season, advanced age, and obesity increase deficiency risk.
Key Tips
- ✓Vitamin D is essential for bone health, immune function, and mood regulation.
- ✓Deficiency is common in winter months and in northern latitudes.
- ✓The Endocrine Society recommends 1,500-2,000 IU/day for adults, more if deficient.
- ✓Sun exposure is the primary source – 10-30 minutes midday without sunscreen.
- ✓Always consult your healthcare provider before starting high-dose supplementation.
Related Calculators
Understanding Vitamin D Levels
What is Vitamin D?
Vitamin D is a fat-soluble vitamin essential for calcium absorption, bone health, immune function, and mood regulation. It is produced in the skin when exposed to sunlight and is also found in fatty fish, egg yolks, and fortified foods.
Normal Ranges
Deficient: <20 ng/mL (50 nmol/L). Insufficient: 20-29 ng/mL (50-75 nmol/L). Normal: 30-100 ng/mL (75-250 nmol/L). Toxicity: >150 ng/mL (375 nmol/L).
Risk Factors for Deficiency
Dark skin, low sun exposure, winter season, advanced age, obesity, and malabsorption conditions. Dietary insufficiency also contributes.
Supplementation Guidelines
Maintenance: 600-1000 IU/day for adults. Loading dose: 50,000 IU/week for 8 weeks (if deficient). Always consult your healthcare provider.
Example: 35-Year-Old, 25 ng/mL Vitamin D Level
Female, 35 years, vitamin D level 25 ng/mL, moderate sun exposure, winter season.
- Age
- 35 years
- Gender
- Female
- Vitamin D Level
- 25 ng/mL
- Sun Exposure
- Moderate
- Season
- Winter
- Vitamin D Status
- Insufficient (20-29 ng/mL)
- Recommended Supplement
- 1,500-2,000 IU/day
- Maintenance Dose
- 800-1,000 IU/day
- Recommendations
- Increase sun exposure, consider supplementation
Frequently Asked Questions
Clear answers to common questions to help you use this calculator confidently.
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