Vitamin D Level Reference Guide
Understand your vitamin D (25-hydroxy vitamin D) test result and what each level means for your bones and health.
These health tools are still being tested and are updated regularly to give you a better experience. Results are estimates for information only — please confirm important results with a doctor. Read the medical disclaimer
Vitamin D Level Reference Guide
Next steps
- Vitamin B12 Level Reference GuideCheck what your vitamin B12 result means — deficient, borderline or normal.
- Daily Vitamin Requirement GuideSee the recommended daily amounts of key vitamins for your age, sex and life stage.
- Corrected Calcium CalculatorAdjust your total calcium for low albumin to get a truer picture of blood calcium.
- Signs of Dehydration and How to Prevent Water Deficiency in the BodyHealth guide
About the Vitamin D Level Reference Guide
Despite plenty of sunshine, vitamin D deficiency is very common in India because of indoor lifestyles, clothing and skin type.
How to use the Vitamin D Level Reference Guide
- Enter your 25-hydroxy vitamin D result.
- Choose ng/mL or nmol/L as shown on your report.
- Press “Check vitamin D”.
Reference ranges & how it works
Widely used ranges (Endocrine Society) for 25(OH)D:
Below 20 ng/mL — deficient · 21–29 ng/mL — insufficient · 30–100 ng/mL — sufficient · above 150 ng/mL — risk of toxicity
nmol/L = ng/mL × 2.496
Worked example: Vitamin D Level Reference
A result of 18 ng/mL is deficient (below 20 ng/mL). In nmol/L that is 18 × 2.496 = 45 nmol/L.
Important limitations
- Experts disagree on the exact “sufficient” level (20 vs 30 ng/mL).
- Assay methods differ between labs.
- Reference ranges differ between laboratories; the range printed on your own report takes priority. Discuss abnormal results with a doctor.
Frequently asked questions
What are the symptoms of low vitamin D?
Many people have none. Others notice tiredness, bone or back pain, muscle weakness and frequent infections.
How much sunlight do I need?
Around 15–30 minutes of midday sun on arms and legs a few times a week helps, but many people still need supplements. Your doctor will advise a dose.
Which vitamin D test should I ask for?
Serum 25-hydroxy vitamin D [25(OH)D] — it reflects body stores. The 1,25-dihydroxy vitamin D test is for specific conditions such as kidney disease and is not used to check deficiency.
How long does it take to correct low vitamin D?
With the supplement dose prescribed by a doctor, levels usually improve within 8–12 weeks. A repeat test after about 3 months shows whether the dose is right.
Sources
- Holick MF et al. Evaluation, treatment and prevention of vitamin D deficiency: an Endocrine Society clinical practice guideline. JCEM 2011;96:1911-30.
- Institute of Medicine. Dietary Reference Intakes for Calcium and Vitamin D, 2011.
Medical disclaimer: These tools give general information and estimates only. They are not a diagnosis and do not replace advice from a qualified doctor. Always talk to your doctor about your results, and seek urgent medical help in an emergency. In an emergency call 112. Medical disclaimer · Terms of use · Privacy policy
