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Vitamin D Test Checker

See whether your vitamin D level is deficient, insufficient or sufficient, in ng/mL or nmol/L, and check your B12 and folate too. Free, no sign-up, and your results never leave your device: nothing is uploaded or saved.

  • Read on your device, never uploaded
  • We can't read your results
  • Explains results, doesn't diagnose

Educational only, not medical advice or a diagnosis. Reference ranges differ between labs; your doctor interprets results with your history. Results are only kept if you press Save, and then only in this browser.

More vitamins tests (1)

Enter a value above to see what it means.

Health Pro

£4/ month, cancel any time

  • Trend charts per test, in mmol/L or mg/dL
  • Family profiles
  • Doctor visit sheet (print or PDF)
  • End-to-end encrypted sync between your devices
  • Share a family medicine chart, end-to-end encrypted

Payment is handled by Paddle, our merchant of record, who charges any VAT or sales tax. Your email goes to Paddle and to us to send the receipt and a sign-in link. What you put into the tools is never sent. Terms · Refunds

Read the full guide: Vitamin D Levels Explained: Deficiency, Normal and High

How to read a vitamin D result

Quick answer: To read a vitamin D result, find the unit, check the category and ask about a dose.

  1. Find the unit. Results are in ng/mL or nmol/L; 1 ng/mL equals 2.5 nmol/L. The checker converts either.
  2. Check the category. Below 20 ng/mL (50 nmol/L) is deficient, 20–29 insufficient, and 30–100 sufficient.
  3. Ask about a dose. Treatment depends on how low the level is; your doctor will suggest a dose and when to retest.

Why vitamin D is often low

Your skin makes vitamin D from sunlight. Spending most of the day indoors, covering skin, darker skin, living far from the equator, older age and extra weight all make deficiency common, including in sunny countries.

Different guidelines

The Endocrine Society calls 30 ng/mL or more sufficient, which this checker uses. Some countries and labs treat 20 ng/mL (50 nmol/L) as enough for most people. Very high levels (over 100–150 ng/mL) usually come from high-dose supplements and can be harmful.

Important

This tool explains results in plain words; it can't diagnose anything. Your doctor reads them alongside your symptoms, history and medicines.

Frequently asked questions

Is vitamin D of 15 ng/mL low?

Yes, under 20 ng/mL is considered deficient. It's common and usually treated with supplements; ask your doctor for the right dose.

What is 50 nmol/L in ng/mL?

20 ng/mL. Divide nmol/L by 2.5 to get ng/mL.

Are my results uploaded or stored?

No. The report is read inside your browser, on your device. Nothing is sent to a server or saved after you close the page.

Discussion

No questions here yet. Stuck on something, or found a trick worth sharing?